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1. a d mu T Dz G1 59 DuPont SUVA Refrigerents Service Manual PRESSURE MPa PRESSION MPa DRUCK MPa i tn re Hx Pt ni G60 e o e ew e i 105 opa ady on nm B pans ra O m m re gt D DI 1 CE n XL D Pret m fewrmenand Moana TET 460 SPEZIFISCHE ENTHALPIE SPEZIFISCHE ENTHALPIE tkd kgi aat ENTHALPIE SP CIFIQUE X l ka ENTHALPIE SP CIFIQUE kiku 210 SPECIFIC ENTHALPY Pressure enthalpy of SUVA HFC 125 SPECIFIC ENTHALPY kal T5 z copog z a Cana p A ra Em iF ri TE S i m misc dao a Di 9 yanya eg NOISS3Hd HP 3HrSS3tid 60 Appendix SPEZIFISCHE ENTHALPIE ENTHALPIE SP CIFIQUE kuka SPECIFIC ENTHALPY iki noo 6020 bag fio sia de abo 280 No A 200 3220 1802 3M dan 44D 1M 140 REFES Kipaman ow mo UM nas d PRESSURE MPa PRESSION MPa DRUCK MPal sense con a g d 38383 8 POT CAMOUE RIT SCHEH FLEET w x du a Pressure enthalpy of SUVA HFC 134a eq MONH EO NOlSSdHd 9 3HIISS3Hd ta EBD zm san wn wo xD Ferd in barman mcr h ans 260 SPEZIFISCHE ENTHALPIE ikdikgi 300 M ab tap Yikkg ENTHALPIE SP CIFIQUE 1H
2. Insufficient sub cooling When installing a moisture indicator note that 1 It must not be heated above 135 C This means that it must be cooled while being soldered to the line or the indica tor itself and the gasketing material of the sight glass will be damaged 2 Particularly in a large system it is a good idea to install the indicator on a by pass line parallel to the main liquid line Itis enough for the indicator to have only a small refrigerant throughput to reach equilibrium It will also be less influ enced by the presence of impurities 3 The moisture indicator may be mounted either upstream or downstream of the liquid line filter drier An upstream position makes it possible to place the filter drier closer to the expansion device and may give earlier indication of the pres ence of excess moisture A downstream position will show at once if the filter is blocked as bubbles will appear in the sight glass 7 5 Field drying All refrigeration and air conditioning systems should be thoroughly dried in the field before charging with refrigerant Whenever any part of the system is opened air and water can enter It is necessary to remove these contaminants to ensure that subsequent operation of the equipment will be as free of trouble as possible Even with factory charged and sealed units it is desirable to evacuate and dry connecting lines and other parts that may have been open to the air even if only for a
3. Tij L4 Th TA ae CST E mue Lh LT XL LI i STI F ani m LP L DT INL LITE lt LLI ZUM Pressure enthalpy of HFC 23 70 B Vibes a HI O HIE ITI sau 38S5 x oo A az m ss rs m sus s K a in Mr V N 1 Y CC YR CUNT rth rH LEX EPI C E ETI KED INICIO AME RSA K N TA KE IKE N m SAT BAYE MS Pu IL 3HnsS3Hd ENTHALPY kJ kg Appendix yon q uoisseJg inss id 1eq 9661 uepur1oW O N HENNO TS uone nuuoj uo peseq eidjeuju 3 7 djeuu3 dOHdd3H LSIN p lnduuoo s ru do d 009 00 I i r _ 100 o o edIN YONG 5 e nsse d Pressure enthalpy of SUVA HCFC236fa 71 DuPont SUVA Refrigerents Service Manual m J Pressure enthalpy of SUVA 95 72 Edl aunssaig gut t Wo 878 Bc6 6 01 0 Se E ing ud 01 rz J E Sa au rg gt a e Dt ae a TE I HH HI
4. Dos ggr D p doz Dar 3Id TY H1N3 GHOSHIZ3dS 3n0142345 3id TVH IN3 Ad Te HIN 210395 Saard 3 ca PA LE um cu ri Tg EQ 3H1SS3Hd Eq NDISS3Hd HEQ YIN 64 Appendix SPEZIFISCHE ENTHALPIE ik kl ENTHALPIE SPECIFIQUE SPECIFIC ENTHALPY tk likgl PRESSURE MPa PRESSION MPa DRUCK MPa ak l sr E Campum imo h o c e E35 Pressure enthalpy of SUVA 404A pum e I ri r m BRSPERS 4 UE AONE 99 NOISS3Hd 12201 HASSE Zu O04 e us mus Our Oa eau a2 c Premed Svrimriared si wan pus SPEZIFISCHE ENTHALPIE I kg ENTHALPIE SP CIFIQUE SPECIFIC ENTHALPY kJ 65 DuPont SUVA Refrigerents Service Manual Pressure enthalpy of SUVA HP 80 66 ALLES L D unii NE Wi Stipa G m IL TP Tez METHA PIE Ea Tin H i pt Appendix PRESSURE MPa PRESSION MPa DRUCK MPa FAT TI En rare ma u ee Soro M uas uu ET did TH INS 3HO5lHIzZ3ds Dos Li Sid WHINE HISS ier 3nnuizds alg TVHLENS ons pat oor Gyr INDEIOSdS E Ae THING 21410985 Oc UI Ol Pressure enthalpy HP 81 of SUVA pat Dil 4 4 212345 001 a 5 FHSS
5. Note If the system contained heavy contamination when started up after fitting the new filter driers the filters may become blocked very quickly 10 6 Follow up Irrespective of the method of clean up used regular visits at intervals of about two weeks should be make to a system that has suffered a burn out These visits should always include inspection and acid test of the lubricant The lubricant and the cores of the filter driers should be changed as often as necessary until the lubricant is clear and free of acidity only then can it be said that the job is complete 37 DuPont SUVA Refrigerents Service Manual 11 Charging refrigerant into system 11 1 Importance of proper charging The main job of a service engineer is to keep highly precise modern mechanical cooling system running as the design engineer intended It is essential to know the proper way to handle refrigerant and the best methods of charging or adding refrigerant to all types of systems All systems do not use the same refrigerant All systems do not use the same amount of charge even though capacities may be entirely comparable 11 2 Check the name plate on factory assembled systems All manufacturers include a name plate that clearly lists the refrigerants for which the system was designed It also fre quently states the amount of the refrigerant charge Always check the name plate before charging or adding refrigerant to a system How much c
6. e u zOL LS 8 20198 z OL E89 z OL GEL z0L 69 600 89800 600 vc800 4900 cL0 O 0L80 0 860 0 8800 OI w M AyAnonpuoo Builioq 7491 v9c L 9vc V coc 0 OLc O v6L vocc 6916 VLCC Vc VVIL 6 91 CULL v egc GEET O C uonesuodeA jo eH Sev S 9L S8 LL SG L vec LEEL 6178 989 ELL 99 9 181 8 L6 0 VOL Jeq 2 92 e1nsseJd 1nodeA Jeq LO L O GZ inoden e u 9c8 0 6c8 0 0 8 0 GZZ 0 99 0 vcL Oo Sv 0 G Z 0 98 0 608 0 1 0 0 9 0 1990 r8 eau 9 JI99d8S 2 o0E e u ye8 l 1891 0891 OvE L 028 1 O L 8 1 081 A LE L ELL 696 0 Qvvl XBA 26Z Ids 2 8L noder 811 81 rL LL 96L 8L 06 9L 6 6L LYTS cL 9 ELLL 8878 89 9 966 G 88 L eu By pajeinjes Ausueq GEE 90L QELL 8r0L 9 LSLL 6LL V6LL 90cL L68LL VIEL gorl 0 9 VELL gUu B 2 92 Ausuep pinbr 9 88 6 88v 8 908 S v8v 089 LLYS Les ECLS 9 OLG ESLS 6LLS g e99 0 0GG 0 9 9 Aysuep eani 6 6V 0 9v TELE Sv vv G LV c8 9v 99 v 9 09 07 0 9 Ege 89 9 6 Jeq eunssaJd eon OYL VeL L 98 VeL 9 78 G Gz 90L ELL 80L ULOL 0 99 L E8L 6 9 0 96 2 enje1eduue e u e u e u e u e u e u e u e u e u OLOL 0801 O66L OZOL TSSL 0 09L Io 6u zaa14 8g a Lo 9 ev L 9v vLv c 6v LYE v8c 0 L 9c L 8r 6 2 0 8 0 Do 4eq L0 L Bulog 6896 SCL 98 9 76 LLV6 8 Z6 O LOL vv6 0 0L 0 0c
7. uou uou uou uou uou uou 96 OA A1iliqeuuuue j 9 097 1e ue e6 Je su e u e u e u e u e u e u e u e u e u LL O L0 O 20 0 80 0 g u L O 96 1 u 492M JO Ajjiqnjios 2 6Z 18 1938M e u e u e u e u e u e u e u e u e u SVO 60 0 SvL O 68 0 00 08 0 96 1 94 jo Auignjos 96 VOL OL0v VVOU L8dH 08dH 994 SdIN 6EdINI evel 921 vel EZL c cc eVANS VANS VANS VANS VANS VANS VANS VANS VANS VANS VANS VANS VANS OdH sNO4dd4 SHUN Auedoad eo sAUd pauoo sjueoSugo1 S VA rS Jo sen1edoud peors amp uqd 55 DuPont SUVA Refrigerents Service Manual Pressure enthalpy mollier diagrams for FREON 22 SUVA HCFC 123 SUVA HCFC 124 SUVA HFC 125 SUVA HFC 134a SUVA MP 39 SUVA MP 52 SUVA MP 66 SUVA 404A SUVA HP 80 SUVA HP 81 SUVA 407C SUVA 410A HFC 23 SUVA 236fa SUVA 95 SUVA 507 56 Appendix HHO B31DnOcc Ew ST orsi in 3851252 3198 di ni r sd m M ka Le E A E a g B WAJE lia m Aire K di 8 i 4ak EM x E E j g 3 a E r E x Pressure enthalpy diagramme FREON 22 it ia Pde Faia be pu oer ini gree E w 1 a E 3 22553 i E E H E R SSS TE n hagas VOPR ISH TT GET NOSE Hure LL eee 57 DuPon
8. Heg NOISS3H4 Aono 67 DuPont SUVA Refrigerents Service Manual Pressure enthalpy of SUVA 407C 68 eq ainss id PRE j ll Eq 3 oe race EIN eissald lt Bran i T a od Wa l nan muma ra Ei K d SE HES N Hii h gt Tank l Ew 3 gt ENTIS EE REC 1 TUE a D x oh 950 500 450 400 S00 250 200 150 10D E nthalpy kJ kg Appendix Enthalpy kJ kg dW ainss id i mo 8 5 8 SOT PULL E mie ee et A E um 2 j J 1 08 is m eem 3 68 s Lom e a wee 3 9 eee F a 1 m F T bum i U 3 sB n MU S x 450 js 500 450 350 Enthalpy kJ kg S P ED N NSS e m TR Pressure enthalpy N of SUVA 410A Ti ett Ly VAN R 200 AWA MET S BF T if i i 2 w ea eo ed Edi ainss rd 250 150 100 69 DuPont SUVA Refrigerents Service Manual seq LLLI ice eu ERR HN LU LESS HT TT TTA I Ek n jT 75 p j N AT LA
9. If avail able it is a suitable replacement for R 502 in medium to high temperature applications For CFC 12 or R 502 at low tem perature FREON 22 is more mechanically complicated and more expensive than the service or alternative retrofit options There are some exceptions to the above decision tree m Automotive A C None of the automotive OEMs recom mend anything other than HFC 134a as a retrofit refrigerant m Systems with flooded evaporators generally these refrigeration systems should not use a significantly glided refrigerant They should use instead SUVA 134a or SUVA HP62 m Systems with centrifugal compressors Consult the man ufacturer or qualified consultant as this type of system normally requires significant modifications Retrofitting existing systems 13 3 Converting refrigeration installations from R 12 to SUVA NIP39 and SUVA MP66 CFC 12 is the most widely used CFC refrigerant therefore the majority of conversions will involve replacing CFC 12 SUVA MP blends have been designed to replace CFC 12 in existing equipments calling only for minor modifications to the system as they have thermodynamic properties very similar to those of CFC 12 The blends recommended except for automobile air conditioning are SUVA MP39 or SUVA MP66 13 3 1 Selection The choice between SUVA MP39 and SUVA MP66 will be based on the application and its typical operating conditions SUVA MP39 SUVA M
10. SPECIFIC ENTFIALPY kkg 61 DuPont SUVA Refrigerents Service Manual PRESSURE MPa PRESSION MPa DRUCK MPa Bar O ad Soom aoc M i SOG D ou SPEZIFISCHE ENTHALPIE kar ENTHALPIE SP CIFICIUE ikdikgi Pressure enthalpy of SUVA MP 39 SPECIFIC ENTHALPY kkg EE UD IH Tu mcer iu dau c 1 100 E B 70 ED B ad Meg xod eq NOorlSs3Hd Hdl 553 62 m ce ea F 3 27 LL i a amp 3 mE 250 20 SPECIFIC ENTHALPY IkJ kg 100 Pore ir wanin r Ae na SPEZIFISCHE ENTHALPIE Appendix SPEZIFISCHE ENTHALPIE Tel ENTHALPIE SP CIFIQUE SPECIFIC ENTHALPY k l kg 209 PRESSURE MPs PRESSION MPa DRUCK MPa fase 6 mariam mM F Sane im s ui USE GO o e end O Pressure enthalpy of SUVA MP 52 Rete RUE Seen pep WO ei NOISS3Hd HEA 38n853Hd na Mirisi in Taira din i 13 SPEZIFISCHE ENTHALPIE ENTHALPIE SP CIFIQUE kl SPECIFIC ENTHALPY keg 63 DuPont SUVA Refrigerents Service Manual i Patah 44 Rasan PRESSURE MPa PRESSION MPa DRUCK MPal ETA Ad Tv HLLNS 21219985 Er 3010142345 We Tv HIN fir 3ld Tv H LN3 3H2 SlllZddS ocu EIQ FU SoG a i z gt e 0 tao of 2 lt H gt h 52 ni 2 o Am Qu aA Ill d iz
11. samples of elas tomers were immersed in the liquid refrigerant at room tem perature until maximum or equilibrium swelling occurred Elastomers which swell excessively are not recommended for use in refrigeration systems with SUVA refrigerant 423 Compatibility with plastics A brief summary of the effect of the SUVA refrigerants on various plastic materials is given in the table on the next page but compatibility should be tested for specific applications Differences in polymer structure and molecular weight plas ticizer temperature and other factors may alter the resistance of the plastic to SUVA refrigerants DuPont SUVA Refrigerents Service Manual Compatibility of plastics with SUVA Refrigerants Rating 0 compatible 1 borderline 2 incompatible Refrigerant R 11 SUVA R 12 SUVA SUVA R 22 SUVA SUVA R 502 SUVA SUVA SUVA 123 134a MP 407C 410A HP80 81 404A 124 Plastic Trademark HDPE Alathon 1 1 1 0 1 1 0 0 1 0 0 PP 2 1 1 0 1 1 1 1 1 1 0 1 PS Styron 2 2 1 1 2 2 1 1 2 2 1 1 Polyvinvyl Chloride PVC 1 1 0 0 1 1 0 0 1 1 0 0 CPVC 0 0 0 1 1 0 0 1 1 0 0 Fluorocarbon PTFE Teflon 1 1 1 1 1 1 1 1 1 1 1 1 Tefzel 1 1 1 2 1 1 1 1 1 1 2 PVDF 0 0 1 1 1 1 1 1 1 0 0 lonomer Surlyn 2 1 0 1 1 0 0 1 1 0 1 Acrylic Lucite 0 2 0 2 2 2 2 2 2 2 2 2 ABS Kralastic 0 2 0 0 2 2 2 2 2 2 0 2 Cellulosic Ethocel 2 2 2
12. 2 2 2 2 2 2 2 2 2 Epoxy 0 0 0 0 0 0 0 0 0 0 0 0 Acetal Delrin 0 1 0 0 1 1 1 1 1 0 0 0 Noryl 2 0 0 2 2 1 1 2 2 0 0 PC Tuffak 0 2 0 0 2 2 1 2 2 0 0 Polyester PBT Valox 0 0 0 0 0 0 0 0 0 0 Polyarylate Arylon 0 0 0 2 2 1 1 2 2 0 Nylon Zytel 0 0 0 0 0 0 0 0 0 0 0 0 PI Vespel 0 0 0 0 0 0 PEI Ultem 0 0 0 0 1 1 0 0 PPS Ryton 1 0 0 1 1 0 1 1 1 0 1 Polysulfone 0 0 0 2 2 1 1 1 2 0 0 20 Lubricants and their relationship with SUVA Refrigerants 5 Lubricants and their behaviour with SUVA Refrigerants Lubricants are an essential component of all refrigerant systems A refrigeration compressor requires lubrication like any mechanical equipment Oil is necessary to lubricate the bearings and the pistons in the case of a reciprocating com pressor In addition particularly in a screw compressor the oil acts as a seal it performs this sealing function to a lesser but important extent in other types of compressors Within the compressor the oil helps to absorb and carry away the heat generated by the working of the compressor 5 1 Lubricants for use with SUVA Refrigerants In almost all cases the mineral oils MO previously used with CFC refrigerants should not be used with the new HFC con taining refrigerants This is because these new refrigerants have very different solvent properties from CFCs While the new HCFC containing refrigerants do have a slightly lower miscibility with mineral oi
13. 402A 49 2 C HCFC 22 38 HFC 125 60 HC 290 2 SUVA HP81 R 402B 47 4 C HCFC 22 60 HFC 125 38 HCFC 124 2 SUVA 404A R 404A 46 5 C HFC 125 4496 HFC 143a 5296 HCFC 134a 4 SUVA 407C R 407C 43 6 C HFC 125 25 HFC 134a 52 HFC 32 23 SUVA 410A R 410A 51 8 C HFC 32 50 HFC 125 50 SUVA 95 R 508B 88 0 C HFC 23 46 HFC 116 54 Pure Products HCFCs Boiling Point Chemical Hydro chlorofluorocarbons 1 01325 bar Formula FREON 22 40 8 C CHCIF SUVA 123 27 8 C SUVA 124 12 1 C CHF CCIF Pure Products HFCs Boiling Point Chemical Hydrofluorocarbons 1 01325 bar Formula FREON 23 80 0 C CHF SUVA 125 48 1 C CHF CF SUVA 134a 26 1 C CH2F CF3 HFCs that are flammable as a single product are not desig nated SUVA because of their flammability These products may be used as components in SUVA Blends with non flammable products which suppress their flammability SUVA Blends that contain flammable HFCs are safe to han dle even in the event of a leak or a spill Pure Products HFCs Flam Boiling Point Chemical mable Hydrofluorocarbons 1 01325 bar Formula HFC 32 51 7 C CH F HFC 143a 47 7 C CH3 CF3 HFC 152a 24 1 C CHs CHF DuPont SUVA Refrigerents Service Manual 3 2 Selection of DuPont refrigerants The choice of a SUVA refrigerant will depend on the appli cation as well as on the type of CFC to replace Typic
14. 5 Critical point Pressure bar Subcooled liquid region Superheated vapor region Liquid vapor mixture Saturated Vapor line Enthalpy kJ kg SUVA refrigerants The pressure enthalpy is as follows Fig 6 Pressure bar Superheated vapor region Subcooled liquid region gt 5 o we Liquid Xu ae quid vapor gom gt mixture M Cet LX Saturated vapor line Enthalpy kJ kg a Expansion Pressure bar 7 bar Enthalpy kJ kg The pressure drops from 7 to 1 bar Fig 7 the enthalpy or internal energy stored in the refrigerant SU VA 134a is 237 kJ kg We can see that part of the refrigerant has vaporized This expansion or pressure drop takes place through the Expansion Device which is typically a thermostatic expansion valve automatic or electronic expansion valve capillary tube hand operated valve DuPont SUVA Refrigerents Service Manual b Evaporation Pressure bar 7 bar Evaporation Enthalpy kJ kg In order to vaporize the refrigerant increases its enthalpy from 237 kJ kg to 383 kJ kg Fig 8 in other words one kilo gramme SUVA 134a absorbs 146 kJ to complete the change into vapour at 5 2 kg m c Compression Pressure bar Compressor exit temperature Compression Qep Enthalpy kJ kg 383 440 During compression Fig 9 the refrigerant takes up energy heat corresponding t
15. Newton is applied in its own direc tion over a distance of 1 meter Power Watt W 52 1 Watt is the power produced when work is performed at the rate of 1 Joule per second Appendix Other conversions Temperature 273 15 F 459 67 1 8 R 459 67 C 273 15 x 1 8 F 32 1 8 F 1 8 32 Conversion factors To conv ert from To Multiply by Pressure 1 atm bar 1 01325 1 Pa N m bar 10 5 1 kg m2 bar 0 98066 10 4 1 kg c m2 bar 0 98066 1 Torr mmHg bar 1 333 103 1 mH20 bar 0 9805 10 1 1 Ib sq in psi bar 6 80474 10 2 1 in H20 4 C bar 2 491 10 3 1 ft H2O 4 C bar 2 989 102 Length 1 in m 25 4 10 3 1 ft m 0 30480 1 yd m 0 9144 1 statute mile m 1609 344 1 nautical mile m 1853 18 Surface 1 sq in m2 6 45160 10 4 1 sq ft m2 9 29030 102 1 sq yd m2 0 83613 1 Acre m2 4047 1 sq mile m2 2589998 Volume 1 cu in m3 1 63871 10 5 1 cu ft m3 2 83168 10 2 1 cu yd m3 0 764555 1 US gallon m3 3 78534 10 3 1 Imperial gallon m3 4 54596 10 3 1 US bushel m3 3 524 10 2 1 US fluid oz m3 2 957 10 5 Linear speed 1 m min m s 0 01667 1 km h m s 0 2778 1 cm s m s 10 2 1 mile h m s 0 4470 1 yd s m s 0 9144 1 ft min m s 0 5080 10 2 1 ft s m s 0 3048 1 in s m s 0 0254 1 knot m s 0 5144 Rotation speed 1 RPM Rad s 0 10472 Mass units 1g kg 103 1t kg 103 102 kg 2 83495 10 2 116 kg 0 453592 1
16. a service engineer can remove it The action of contaminants is usually slow system may start up initially and run perfectly a few months or even years later it may be found to be badly damaged perhaps beyond repair The good reputation of a service engineer of an installation or service company and ultimately of the whole industry depends on accurate and conscientious work 6 2 The principal contaminants The principal contaminants are m Air m Water m Oxides m Solid particles Others less frequently encountered are Anti freeze agents Soldering flux Solvents particularly chlorinated solvents Unsuitable leak detection dyes Nitrogen and other gases are included in the paragraph on air 6 2 1 Air Air must be removed from the system to make it possible to charge the refrigerant If a small amount of air remains the system will be able to operate but there will be problems Air includes atmospheric moisture which will cause rust ing of iron or steel parts and corrosion of other parts Air will oxidise the lubricant causing it to form sludge and will oxid ise other components 26 Air and other gases such as nitrogen have an additional bad effect The general name given to these gases is non condensible gas NCG At normal compressor operating temperatures these gases are not compressed as readily as SUVA Refrigerant vapour This causes higher pressure and consequently higher temperature in th
17. also made use of earlier work by Paul Crutzen During the following fifteen years the theory was discussed and questioned but although the numerical calculations have been changed the broad lines of the theory are now generally accepted Because of their chemical stability CFCs do not break down and cause pollution in the lower atmosphere or tropo sphere They are carried intact up to the level of the Ozone Layer where under the effect of direct sunlight they do break down The chlorine radicals that are released by this chemi cal decomposition then react with ozone molecules in the Ozone Layer converting them into normal oxygen The chemical reaction simplified is CCIF 2 x CI CF CFC 12 chlorine unstable radicals CI O2 CIO chlorine ozone oxygen chlorine radicals monoxide CIO 2x0 This reaction then repeats itself very many times It is this catalytic cycle that causes depletion of the Ozone Layer The Ozone Theory remained a theory without proof until 1987 In that year the British Antarctic Survey reported a series of observations over twenty years which showed that the Ozone Layer over the South Pole diminished consider ably each year in the Southern Hemisphere Spring the decrease becoming more significant each year during the pre vious ten years This is what is called the Antarctic Ozone Hole A NASA expedition using high flying aircraft and bal loons confirmed the gro
18. and centrifugal types Compressor OEMs specify the types of lubricant suitable for use in their compressors primarily by their viscosity In most cases the compressor is shipped from the factory charged with lubricant from a particular supplier The OEM s technical bulletins normally specify a number of lubricants from other suppliers which are technically acceptable as ser 22 vice replacements These include retrofit guidelines for changing from CFC to replacement refrigerants This is based on the testing and experience of that manufacturer In the USA oil viscosity is measured at 100 F 37 8 C by a different method and the result is expressed in Saybolt Universal Seconds SUS or SSU The two scales do not cor respond exactly but for the viscosities most frequently encountered an approximate conversion is m 150505 32 cSt m 300SUS 68 cSt m 450SUS 100 cSt 5 5 2 Viscosity in a Refrigeration system The lubricant in a refrigerant system is exposed to very con siderable variations in temperature For example with a her metic compressor system charged with HCFC 22 evaporat ing at 40 C the compressor discharge temperature may be as high as 177 C The oil in circulation with the refrigerant therefore experiences a temperature difference of over 200 C in a period that may be only a few minutes In addition to the effect of temperature on the viscosity of the oil the refrigerant also affects the viscosity Refrigerant di
19. and the development of hydraulic pressure which may be sufficient to rupture the cylinder Do not over fill cylinders If a cylinder is full of liquid refrigerant the pressure increases very rapidly with only slight rise in temperature Under these conditions the cylin der may burst Do not damage cylinders A cylinder must not be dropped or used as a roller or support If a cylinder or its valve is or appears to be damaged do not attempt to repair it This is a job for a specialist Return it to your SUVA refrigerant distributor Lubricant from a refrigeration system should be handled carefully It may contain acids particularly after a burnout Wear gloves protective clothing and eye protection Flush pipes with dry nitrogen when brazing or welding part of a refrigeration system Release pressure of any system or component before welding or brazing Systems and components such as com pressors and heat exchangers are frequently pressurized to more than normal working pressure for leak testing If repaired by welding or brazing while still under pressure the rise in temperature may increase pressure sufficiently to rupture the component Never use oxygen to flush pipes or parts of systems Oxy gen and refrigeration lubricant can form explosive mixtures 14 1 5 First aid Frostbite Warm the affected skin to body temperature as soon as possible Eyes If SUVA refrigerant is splashed into the eyes rinse with plenty of wa
20. be replaced for that reason ond lubricant charging procedure This is the same in all the cases above 1 Equipment required m Vacuum pump m Charging line fitted with a shut off valve and a screw connection to match the thread of the lubricant filler plug on the compressor 24 m Pressure gauge not absolutely essential but useful 1 Pump down the system to reduce loss of refrigerant then isolate the compressor by closing both service valves Con nect the vacuum pump to one of the service valves Reduce pressure within the compressor to a slight positive pressure approx 0 1 bar then stop pump Remove compressor lubri cant plug screw in charging line with shut off valve closed 2 Carefully open suction service valve Let sufficient refrig erant vapour enter the compressor to restore the slight posi tive pressure then close suction service valve Open the shut off valve in the charging line to purge air Remove cap from lubricant container and insert the end of the charging line to the bottom Close shut off valve 3 Re start vacuum pump When pressure in the compressor is slightly below atmospheric open the shut off valve care fully Fill lubricant to correct level as shown in compressor sight glass then close shut off valve 4 Stop vacuum pump restore slight positive pressure by opening the suction service valve as before Disconnect charging line and replace lubricant filler plug This method of c
21. during the process of evaporation of these refrigerants at constant pressure there is an increase in the temperature This increase in temper ature is called the Evaporator Temperature Glide Isotherms A bubble point Pressure Critical Point B dew point Constant pressure p Enthalpy Conversely during condensation as the vapour quality decreases there is a fall in the equilibrium condensing tem perature at constant condensing pressure Condenser Tem perature Glide These Temperature Glides are different for each refriger ant and the Evaporator Glide is often a slightly different value than the Condenser Glide for a given refrigerant In the case of the SUVA refrigerants the Evaporator Glides range from around 0 5K for SUVA HP62 to as much as 6K for SUVA 9000 The Saturation Property Tables of these non azeotropic refrigerants are slightly different in format from those for single component or azeotropic refrigerants The non azeotropes have two different Saturation Pressure Tempera ture curves one for the Saturated Liquid also known as the Bubble Point and the other for the Saturated Vapour also known as the Dew Point This compares to the one curve rep resenting Saturated Liquid arid Vapour for single refrigerants or true azeotropes In the property tables for non azeotropes or blends the different Pressure Temperature values for both Saturated Liquid and Saturated Vapour are given 16 The Pressu
22. is still hot Do not cool the joint rapidly while the joint is near the solder melt ing temperature 34 9 6 2 Large diameter tubing Large diameter tubing must be brazed piecemeal To make a sound joint with large tubing play the flame alternately from tube to fitting while melting the brazing alloy over a small section of the joint Each additional bit of alloy must be drawn into the joint and fused with the alloy already in place Iftoo much flux is applied you can end up with a poor joint The flux can occupy space intended for brazing metal in the fitting In time the flux will break away and the joint will leak Double tip torches are available for use on large diam eter tubing so that the tubing can be heated more uniformly In some cases two torches can be used 9 6 3 Low melting silver bearing solder Low melting silver bearing solder is easy to use with differ ent metals and is especially recommended for use in the food industry Silver alloys containing cadmium should not be used on components that may come into contact with food because of the possibility of cadmium poisoning 9 7 Breaking soldered or brazed joints 9 1 Servicing all types of refrigeration systems In servicing all types of refrigeration systems it may be nec essary to break refrigerant lines to repair leaks at a connec tion or joint or to replace components such as expansion valves compressors condensers or evaporators Don t apply he
23. normally with its final charge expect to find m In most cases the suction pressure will be very close to that when operating with R 12 m Thedischarge pressure will normally be between 0 7 and 1 4 bar higher than with R 12 12 Adjust the high pressure and low pressure safety cut outs if necessary 13 Carry out complete leak check 14 Replace the R 12 sticker by a SUVA9 MP39 or SUVA MP66 sticker as appropriate On the same or on a separate sticker record the type and viscosity of the new lubricant Complete the retrofit report with the new operating parameters of the system Retrofitting existing systems Note Any welding or brazing operation for example change of the filter drier must be carried out under an inert nitrogen atmos phere to avoid any risk of carbon or copper oxide formation 13 4 Converting refrigeration installations from R 502 to SUVA HP80 and SUVA HP81 R 502 is an azeotrope consisting of 48 8 wt HCFC 22 and 51 2 wt CFC 115 It has until now been widely used for low temperatures down to about 40 C Principal applica tions were in frozen food and ice cream cabinets and in refrigerated trucks and containers Because CFC 115 is a CFC and also a long lived green house gas R 502 is banned in the same way as CFC 12 and other CFCs SUVA 80 and SUVA HP81 Refrigerants have ther modynamic properties similar to those of R 502 They were developed specificall
24. oceans Man made sources of methyl bro mide have been identified as soil fumigation biomass burn ing and automobile exhausts from cars running on leaded petrol 1 4 The future of the Ozone Layer The future of the Ozone Layer as of late 1995 appears rea sonably satisfactory provided that the actions already taken are continued according to the terms of the revised Montreal Protocol The rates of increase in atmospheric concentration of several major ozone depleting substances including spe cifically CFC 11 and CFC 12 have slowed down Organic chlorine in the troposphere increased by only 1 6 in 1992 compared to 2 9 in 1989 The loading of chlorine and bro mine in the troposphere is expected to have reached its peak in 1994 because of the time taken to assemble and analyse the data this is not yet confirmed and begin a slow decline from then onwards The peak loading in the stratosphere is expected about 3 5 years later Ozone depletion is therefore expected to continue to the end of this decade with gradual recovery of the Ozone Layer beginning in the 21st Century Introduction 1 2 Global warming 1 2 1 The global warming issue Global warming issue is a separate issue and is a global prob lem It affects the whole climate of the earth with major con sequences Increased warming would have serious social consequences Climate change would affect crop yields and possible melting of the polar ice caps could lead t
25. resistance to shear stress 9 3 Vent with inert gas When heat is applied to copper in the presence of air copper oxide forms on exterior and interior tubing surfaces This oxide is easily washed from the tube surface when the system is put into operation and is then free to circulate with the refrigerant and lubricant Lubricant borne oxides are inevi tably exposed to high temperatures at the compressor dis charge valve where the oxides can cause decomposition of the lubricant and refrigerant Itis easy and well worthwhile to prevent oxide formation Isolate the section of line being worked on and sweep an inert gas preferably dry nitrogen through the tubing being brazed Nitrogen will displace air and prevent oxidation of steel pipe or copper tubing at soldering or brazing temperatures The nitrogen should flow just enough to displace the air that is in the tubing From 30 to 90 litres minute is usually sufficient m The nitrogen is usually quite dry but using a drier is good insurance m Itis good business to provide each service truck with a supply of dry nitrogen because of the substantial divi dends which can be realized in better performance of non contaminated systems Whenever working with dry nitrogen certain precautions should be observed The pressure in a fresh nitrogen cylinder at room temperature is approximately 165 bar which is far above the bursting pressure of refrigerant cylinders and com ponents For this r
26. short time The best method of drying equipment in the field is by using a good vacuum pump to reduce the pressure in the 30 system below the vapour pressure of water thus causing it to boil or evaporate and the vapours to be withdrawn by the pump If the deep vacuum is broken by introducing oxygen free nitrogen to above atmospheric pressure and the system is then re evacuated the time required for good dehydration can be reduced and the same degree of dryness produced Ifa good vacuum pump is not available and the system does not contain free water an open type compressor can be used for evacuation When using a compressor two purges with nitrogen are recommended Details of these evacuation methods are given under the section on evacuation Note especially the description of a cold trap to aid in removing water vapour or water from systems A hermetic compressor is not recommended because the design usually requires a flow of cold refrigerant vapour to keep the motor cool When used in evacuation there is lit tle flow of refrigerant so that the motor temperature may become high enough to cause failure If no form of evacuating equipment is available blowing nitrogen through the system will do some good and would be better than not doing anything When preparing systems for use with HFC Refrigerants and POE oils it is essential to use at least two nitrogen flushes and use a good vacuum pump to ensure a deep vacuum Regardless of t
27. 1 11 1 11 2 11 3 11 4 11 5 115 1 11 5 2 11 5 3 11 5 4 11 5 5 11 6 11 7 12 12 1 12 2 12 3 12 3 1 12 3 2 13 13 1 13 2 13 3 13 3 1 13 3 2 13 3 3 13 3 4 13 3 5 13 4 13 4 1 13 4 2 13 4 3 13 4 4 13 4 5 page Charging refrigerant into system 38 Importance of proper charging 38 Check the name plate on factory assembled systems 38 Check manufacturers catalogues 38 Vapour charging 38 Liquid charging 39 Connect the refrigerant cylinder to the charging port 39 Crack cylinder valve and purge charging line 39 Close the valve at the receiver outlet 39 Slowly open the charging port valve and charge liquid 39 Watch the discharge pressure 39 System without a sight glass 39 Charging a small capillary tube system 40 Leak detection 4l Designing to reduce leaks 41 Symptoms 41 Methods 41 Leak detection 42 Pinpointing 42 Retrofitting existing systems 44 Conversion of existing systems from CFC to non CFC refrigerants How to choose the non CFC refrigerant Converting refrigeration installations from R 12 to SUVA MP39 and SUVA MP66 45 Selection 45 Compatibility with materials and lubricants 45 Components to change 45 Equipment required for conversion 45 Conversion procedure 46 Converting refrigeration installations from R 502 to SUVA HP80 and SUVA HP81 47 Selection of the refrigerant 47 Compatibility 47 Components to change 47 Equipment required for conversion 48 C
28. 5 2 kg m DuPont SUVA Refrigerents Service Manual Compressor condensation In order to recuperate the refrigerant vapour at the evapora tor outlet we complete the previous set up as follows Fig 3 Absorbed heat Evaporator Rejected heat y bar f A Condenser Compressor EU Ambiant temperature 15 a Vapour leaving the evaporator enters the compressor with the inlet valve open b The piston goes down and the total volume of the cham ber is filled with vapour c The piston goes up the inlet valve closes the pressure in the chamber increases to 7 bar the exhaust valve opens and the gas at high pressure is let out d The high pressure gas enters the second heat exchanger and gives away heat to the ambient medium Since the gas is giving heat away it changes from vapour to liquid Vapour is condensed in this heat exchanger called a condenser e The liquefied refrigerant is returned to the storage cylin der and the cycle is completed 12 Summary A refrigerant installation is essentially made up of the follow ing components Elements Roles Reserve of liquid refrigerant allowing to compensate for the variations leaks or cooling demand Should be able to con tain all the refrigerant in the system Receiver Vessel on the suction side of the com pressor containing a buffer volume of superhea
29. All SUVA refrigerants except SUVA 123 are liquefied gases shipped under pressure They are supplied in cylinders and other shipping containers which are of adequate strength and which comply with pressure vessel regulations Pressure of SUVA refrigerants at normal tempera ture 25 C range from 0 45 bar Suva 123 to 13 8 bar SUVA 125 Refrigeration equipment must be of suffi cient pressure resistance for the refrigerant employed note SUVA 123 is liquid at room temperature Very slight odour SUVA refrigerants have a slight ethereal odour This can only be perceived if they are present in relatively high con centrations in the air being breathed Vapour heavier than air SUVA refrigerant vapour is up to six times heavier than air It will tend to accumulate in low places almost like a liquid The vapour will displace air if it is present in very large quantities SUVA refrigerant vapour will decompose if exposed to flames or very hot metal surfaces Decomposition products are toxic but warning of their presence is given by very pun gent irritating acid vapours It is almost impossible to remain 50 voluntarily in an area containing more than a few ppm of these decomposition products 14 1 3 Threshold limit value The American Conference of Governmental Industrial Hygi enists ACGIH has recommended TLVs for many industrial chemicals The TLV TWA is a time weighted average con centration in air for a nor
30. B at a constant temperature of 100 C Between B and C liquid will subcool and change from 100 C to say 80 C Fig 1 lewe 0 Water Air 30 YC In the case of SUVA If we consider the case of SUVA 134a 1 1 1 2 tetrafluoroe thane we have the following values Absolute Boiling Latent heat pressure temperature of vaporization bar kJ kg 1 26 3 217 3 2 10 1 206 2 3 0 7 198 2 4 8 9 191 8 5 15 7 186 2 6 21 5 181 1 Refrigeration cycle Evaporation In order to evaporate a refrigerant must absorb heat SUVA 134a 7 bar gt Air 27 YC Let us consider the following installation a In the cylinder SUVA 134a is liquid at 7 bar b The valve is opened c The refrigerant flows into the tube at 1 bar corresponding to 26 3 C Heat is taken from the air at 27 C the air is cooled to 10 and the refrigerant changes state from liquid to vapour The apparatus in which this change of state occurs is an evaporator Fig 2 Remark No 1 If at point all the refrigerant has been changed into vapour between A and B the vapour will be superheated in this example from 26 3 C to 20 C Remark No 2 Each time one kilogramme of SUVA 134a changes state from liquid to vapour at 1 bar it requires an energy heat input of 217 kJ and is changed into vapour at a density of
31. Dew Point values should be used For Condenser Subcooling the Saturated Liquid Bubble Point values should be used 3 The effective Condensing Temperature is the average of the Bubble and Dew Point Temperatures for the given pres sure In calculating the effective Evaporating Temperature allow for the Flash Gas The range of DuPont SUVA Refrigerants 3 DuPont SUVA Refrigerants 3 1 The range of DuPont SUVA Refrigerants SUVA Refrigerants are tailored to replace refriger ants either in retrofitting existing equipment or for first fill in new equipment To ensure optimum performance while maintaining non flammability retrofit refrigerants are usu ally blends All of the SUVA range of refrigerants have very low or zero Ozone Depletion Potential ODP All are non flammable even in the event of a leak or a spill All have very low toxicity The DuPont SUVA range of refrigerants consists of blend and single components or pure products Most of the SUVA Blends have been allocated R numbers by ASH RAE in the R 400 series for non azeotropes DuPont SUVA Boiling Composition Designation Number Point at wt BLENDS 1 01325 bar SUVA 9 R 401A 33 0 HCFC 22 53 152 13 HCFC 124 34 SUVA MP52 401 28 4 HCFC 22 33 152 15 HCFC 124 52 SUVA MP66 R 401B 34 7 C HCFC 22 61 HFC 152a 11 HCFC 124 28 SUVA HP80 R
32. DuPont Fluorochemicals Suva Refrigerants Service Manual Foreword The DuPont Refrigerants Service Manual was first published in 1964 to pass on to service engineers and technicians the knowledge and experience of DuPont scientists and engineers The Manual was revised and updated three times most recently in 1983 and pub lished in seven languages It is now our pleasure to introduce an entirely new re written European edition The new title emphasises the changes that the refrigeration industry has experi enced and adapted to in the last few years Despite these changes many fundamentals remain true Refrigeration is essential to many human activities including the storage transport and distribution of food the conservation of pharmaceutical and medical prod ucts and temperature control in processing industries The losses caused if efficient temperature controlled dis tribution and storage are not available result in waste that the World ecology cannot afford Air conditioning is essential to the effective performance of skilled work and the dimensional stability of precision products in all climates during part if not all of the year Refrigeration and air conditioning systems use refrig erants that are chemicals under pressure For the safety of the people who work shop or live close to refrigerated equipment or in air conditioned spaces refrigerants should whenever possible be non flammable non ex plosive and o
33. I SEDE Eg eun 58Jg 400 150 200 300 Enthalpy kJ kg 100 Appendix YONG e nsse q 100 80 0 6 0 2 0 1 600 based on mixture model of E W Lemmon amp R T Jacobsen 600 60 40 20 10 8 6 4 2 1 0 Pressure enthalpy of SUVA R507A y o o o o edIN uorssa4g eanssejg Int J Thermophysics 20 1629 1638 1999 Enthalpy Enthalpie Enthalpie kJ kg version 6 01 properties computed with NIST REFPROP 73 For more informations please contact Deutschland Espa ia Portugal France Italia United Kingdom Eire All other countries Du Pont de Nemours Du Pont Ib rica S A Du Pont U K Ltd Du Pont de Nemours Deutschland GmbH Avenida Diagonal 561 Maylands Avenue International S A Du Pont StraBe 1 E 08029 Barcelona GB Hemel Hempstead P O Box 50 D 61352 Bad Homburg Herts HP2 7DP CH 1218 Grand Saconnex GE Tel 93 227 60 73 Tel 06172 87 13 16 Fax 93 227 62 11 Tel 1442 218 533 Tel 22 717 52 96 Fax 06172 87 13 18 Fax 1442 218 575 Fax 22 717 61 69 Your SUVA distributor This information corresponds to our current knowledge on the subject It is offered solely to provide possible suggestions for your own experimentations It is not intended however to substitute for any testing you may need to conduct to determine for yourself the suitability of
34. L S 98L g6 GL 0 0 LV 98 jouu 6 1e n29JOJA 9809 VOLZHY 0 glor 4 OLOVY VLODVYH vELH SCL H g L u c H ccu eJnje oueugou 3v HHSV 5 96 VOLU 30v VVvOU L8dH 08dH 99dIN CSdWN 6EdIN epel 91 vcl cl c ecc amp eVANS eVANS eVANS eVANS eVANS eVANS eVANS eVANS eVANS eVANS eVANS VANS eVANS 94H eNOJ H4 SHURA Auado d jeaisAyd 2 a 54 Appendix AI O pues en q uMOJq Uuo99J6 16109 en q uwoJq u9a16 Aneu asol umoijq eDuejo uaa 6 1uBi 1uBi 46i sep Aa48 qui YNO109 08 109 Lv LcO age L97 89 LLL SL6C GOV GEE Scv 9po SNd Buipoo nojoo 3yHHSV YML IY ZL pue 8 000L 000L 000L 000L 000L 000L 000L 000L 000L 000L 000L 000L 0 000L 0001 wdd 13Y uonejeuu uoniu6oo i 1f pue So soA soA So So soA sok So s soA So So So So So pepnjou snjejs S23NI3 L dMD 2OO 404 HLI 4 001 M5 enueiog OOECL O68L 009L OGLE Ovcc 0 9 O6LL 028 080L OOEL ooze 08r 06 0011 0041 BuruueA eqoib Jenue1od Buruuew e u Sv O 88 0 6 0 c 0 E90 1170 CTO 870 8 0 00 0 0 g u veo L L IID jeqo 6 uoq eoo eH 0 0 0 0 00 c00 S 0 0 0 0 0 0 0 0 0 0 0 0 0 900 L 1L OdO Igenu loduon ld p 20 09 lt e u SEA SCL Lr9 ECL 989 e u L89 gr gez e u 02Z S94 GE9 2 eunjejeduue uoniuBioiny ouou ouou ouou ouou ouou ouou ouou uou uou
35. Leak detection is an external method for detecting the losses of refrigerant from a refrigeration system Leak detection is achieved by means of a sensor incorporated in the instrument This is a technology that is rapidly evolving Not all the detec 41 DuPont SUVA Refrigerents Service Manual tors being marketed today are sufficiently sensitive to certain of the alternative refrigerants particularly HFCs which do not contain chlorine Several of the leak detectors require routine recalibration or regular replacement of their sensor capsule It is very important to select a detector that is ade quate for the refrigerants that will be encountered and that its maintenance requirements be understood and adhered to The leak detecting systems available today can be divided into two different groups based on their function m Leak Detection to warn that there is a leak situation m Pinpointing to identify precisely the location of the leak to enable preventive measures to be taken All of these systems require a means of detecting the pres ence of refrigerant vapours in low concentrations in air There are several technologies utilized for the refrigerant detector sensor These result in detectors which are either m Non selective these usually function by detecting a change in the thermal conductivity or heat capacity of air caused by the presence of another vapour m Halogen Specific a variety of electronic technolog
36. P39 is recommended for high over 0 C and medium temperature CFC 12 systems The capacity effi ciency of SUVA MP39 is comparable to that of CFC 12 in systems operating at evaporating temperatures down to 25 C such as Walk in coolers Food and dairy display cases Beverage dispensers Beverage vending machines Household refrigerators and refrigerator freezers SUVA MP66 SUVA MP66 has comparable capacity to CFC 12 in systems operating at evaporating temperatures below 25 C which makes it suitable for use in transport refrigeration equipment and commercial freezers SUVA MP66 can also be used to replace R 500 13 3 2 Compatibility with materials and lubri cants Compatibility with lubricants See paragraph 5 1 above p 21 Replace the MO which is almost invariably the lubricant in a R 12 system Generally the compressor manufacturer specifies the appropriate lubricant for use with SUVA MP refrigerants in his compressors Materials of construction Itis not necessary to replace elastomers plastics metals wire insulation or other components from the existing R 12 system provided that they are in good condition For the choice of desiccant in the filter dryer see 13 3 3 below 13 3 3 Components to change Filter drier The filter drier or its core must be changed and replaced by a unit containing a molecular sieve desiccant that is compatible with SUVA MP refrigerants Certain filter driers contain
37. ace the compressor Itis possible but not generally advisable to repair a semi hermetic compressor without removing it from the system Repair of a compressor is a job for a specialist The compres sor manufacturer or his appointed distributor will normally undertake this work There are also independent companies that specialize in the repair and rebuilding of damaged com pressors It does not concern the field service engineer whether the replacement compressor which he installs is new or reconditioned provided that it carries an effective guaran tee from a reputable company Recommendations and instructions of the compressor manufacturer should always be followed The following points are given for general guidance in dealing with small and medium sized reciprocating compressor burn outs 10 2 Safety precautions Take care not to inhale the vapours from a burn out Toxic decomposition products may be present Ensure good ventilation at all times Wear rubber gloves and eye protection The lubricant from a burned out compressor is normally acid Avoid get ting this lubricant on clothing 36 10 3 Preliminary inspection Check the electricity supply and the accessible electrical cir cuits The compressor may fail to start for some other reasons If electricity supply is available in all phases and at the correct voltage use a megohmmeter to check for a short circuit between windings or from windings to earth Electri ca
38. al appli cations and the recommended SUVA Refrigerants are DuPont SUVA Refrigerants Application CFC HCFC refrigerants Retrofit New Systems Air Conditioning in buildings and R 11 SUVA 123 SUVA 123 Industrial temperature control R 12 SUVA 134a SUVA 134a SUVA MP39 R 22 SUVA 407C SUVA 407C SUVA 410A Split and Window A C systems R 22 SUVA 407C SUVA 407C SUVA 410A Air and Marine A C systems R 114 R 12B1 SUVA 124 SUVA 124 SUVA 236fa Automobile Air Conditioning R 12 SUVA 134a SUVA 134a SUVA MP52 Fresh food storage above 0 C R 12 SUVA MP39 SUVA 134a Domestic Refrigerators Drink Coolers Commercial R 12 SUVA MP39 SUVA 134a and Restaurant non frozen chilled food storage Light commercial refrigeration R 22 SUVA 404A SUVA 404A SUVA 404A Frozen Food storage below 18 C R 502 SUVA HP80 SUVA 404A SUVA HP81 Refrigerated Transport R 12 SUVA MP66 SUVA 134a Low Temperature Transport R 502 SUVA HP80 SUVA 404A Medium Temperature commercial R 12 R 500 SUVA MP39 SUVA 134a refrigeration SUVA MP66 Low to Medium Temperature R 22 SUVA 404A SUVA 404A commercial refrigeration Very low temperature R 13B1 SUVA 410A SUVA 410A R 13 HFC 23 HFC 23 R 503 SUVA 95 SUVA 95 n direct expansion systems only This list is intended as a guide to cover the situations most likely to be encountered The equipment owner may request the us
39. an that previously or normally fitted if available in the same length Otherwise change the filter drier or its core within 24 hours 10 5 2 System is heavily contaminated When the system is heavily contaminated further action is necessary Two methods are available the Filter Drier method is normal but flushing with refrigerant or oil may be used The refrigerant or oil must be the same as is to be used in the system after it is returned to service In either case all restrictive devices such as expansion valves solenoid valves and filter driers should be removed and either replaced or cleaned 10 5 3 Clean up filter drier Clean up filter drier sometimes called the System Cleaner Method is generally recommended by compressor manufac turers The procedure is simple in that the system is brought back into operation rapidly using a fresh charge of its normal refrigerant Replaceable core filter driers described as Burn out or Clean up type are installed in both the suction line and if possible one size larger than normal in the liquid line Careful follow up is necessary the field service engineer responsible must allocate the time necessary for this It is necessary to check the pressure drop across the filter driers and change the cores as required also check the head pressure of the compressor because non condensable gases may have been produced Follow the detailed instructions given by the filter manufacturers
40. as a lubricant This does not always happen and lubricant may accumulate in the circuit The two main effects of this are to starve the compressor of lubricant which may cause lubrication prob lems and the refrigerant circulation may be obstructed with a consequent loss of efficiency One possible reason for poor lubricant return may be using a lubricant with too high viscosity As noted above compressor OEMs specify the lubricant viscosity but may suggest a range of viscosities If lubricant return is a problem it may be useful to check that the lowest recommended vis cosity is in use Since the evaporator is the coldest point in the circuit it might be assumed that lubricant viscosity will be highest there This is not always the case Because of the dilution effect of refrigerant dissolved in the lubricant highest vis cosity is normally found in the suction line at the point where the superheat increase in temperature above the evaporating temperature is about 20 25 C A heat exchanger between the liquid and suction lines can usefully be fitted at this point System geometry and line velocities can help to physi cally move the oil through the system and back to the com pressor even for immiscible lubricant refrigerant mixtures Field experience with R 401 A and R 402A has shown that mineral oil can successfully be returned to the compressor in systems such as refrigerator freezers with the compres sor located at the
41. at to a line under refrigerant pressure The hazard of line rupture or refrigerant propelled molten solder will always be present Don t unsolder a connection in a line under vacuum because air and moisture will enter and contaminate the system To keep air and moisture from entering the system when breaking a joint apply a very slight positive pressure on the system before opening it to the air Clean the outside of the joint and apply flux Heat the fitting evenly until the solder melts and the joint can be separated Cap all openings to the system immediately Use flare plugs or flare caps if the system uses flare fittings For unsol dered connections use an elastomer or mastic as a sealer Brazing and soldering 9 7 2 Some local corrosion Some local corrosion will result from decomposition of the refrigerant so clean the mating parts thoroughly before rejoining them Provide good ventilation to remove irritating fumes from the working space because the flame may come in contact with a small amount of refrigerant present in the line and cause it to break down Resulting vapours are more irritating than dangerous Never apply a flame to any part of a system containing ammonia vapour 9 7 3 Epoxy compatibility Epoxy resins are compatible with the SUVA refrigerants and are used in refrigeration service work In many cases they can be used in places where soldering or brazing would be difficult Techniques of appli
42. base of the unit Systems with long runs of piping or with low points in the piping which can trap oil need a more miscible lubricant such as AB to return oil to the compressor The suction line should have sufficient gas velocity Rec ommended viscosities are approximately 3 5 m s 200 m mn in horizontal lines and 7 5 m s in vertical risers Velocities should not exceed 15 m s to reduce noise and to avoid exces sive pressure drop Good piping design in larger systems includes sloping the line towards the compressor and install ing traps at the top and bottom of vertical lines 5 5 4 Lubricant separator A lubricant separator is a device normally fitted in the hot gas line immediately downstream of the compressor which separ ates lubricant droplets from the refrigerant stream The lubri cant is then returned directly to the compressor which elimi nates or at least reduces lubricant circulation problems A lubricant separator is essential with a twin screw compressor which uses large quantities of lubricant It is useful in a system that combines a compressor whose manufacturer specifies a high viscosity lubricant with a low evaporating temperature A lubricant separator should always be fitted in a flooded evap orator system and is recommended for any system with long or complex piping runs or low gas velocity Many compressor OEMs include a lubricant separator as a standard option They can also be purchased as a separate it
43. cally similar to CFCs with the important difference that HCFCs contain one or more hydrogen H atoms The presence of the hydro gen atom makes the HCFC molecule less stable in the atmosphere than a CFC consequently less damaging to the Background information ozone layer but not completely non damaging Best known HCFC is HCFC 22 CHCIF Others include HCFC 123 CF CHCL HCFC 124 CF CHCIF HCFC 141b CCLE CH3 and HCFC 142b CCIE CH HFC hydrofluorocarbon Saturated aliphatic molecule containing carbon fluorine and hydrogen Specifically a HFC does not contain any chlorine or other halogen and con sequently has no ozone depletion effect they all have zero ODP Best known 15 HFC 134a others include HFC 125 and HFC 23 CHF Several HFCs are flammable HFC 32 CHF HFC 152a CH3 CHF and HFC 143a CH3 CF Mixed with other non flammable refrigerants these may be used in non flammable blends PFC perfluorocarbon Molecule contains carbon and flu orine only Sometimes referred to as FC Examples are PFC 14 CF and PFC 116 CF3 CF Perfluorocarbons are generally very long lived greenhouse gases BCFC bromo chlorofluorocarbon Similar to CFCs but with one or more bromine Br atoms in the molecule Some times referred to as halons because their principal applica tion used to be as fire extinguishing agents R 13B1 CBrF has been used as a refrigerant The bromi
44. cation have been worked out and information can be obtained from the supplier or manufac turer Specify that it is for a refrigeration system application 35 DuPont SUVA Refrigerents Service Manual 10 Motor burn outs 10 1 General The majority of systems that are charged with SUVA Refrigerants have hermetic or semi hermetic compressors This type of compressor has several advantages over the open type but it does present one problem If the electric motor that drives the compressor burns out the decomposition products will be transformed by the refrigerant throughout the system necessitating a thorough clean out of the entire system The compressor obviously has to be replaced Both the frequency of burn outs and the amount of con tamination in the system have been reduced by protective devices such as thermistor controlled electrical cut outs fit ted by compressor manufacturers Nevertheless burn outs do occur and the field service engineer must know how to deal with them In order to avoid repeat burn outs it is essential to 1 Remove all carbon and other solid deposits Carbon that is carried by circulation of the refrigerant to the replacement compressor is very likely to cause a repeat burn out 2 Remove entirely any contaminant that is accidentally or deliberately introduced during the clean up operation The most frequent such contaminants are air water and solvent Itis almost always necessary to repl
45. condi tions of use At very high temperature such as experienced during brazing some of the metals may act as catalysts for the breakdown of the compound Magnesium alloys and aluminum containing more than 2 of magnesium are not recommended for the use in systems containing SUVA particularly where water may be present Most of the halocarbons may react violently with highly reactive materials such as the alkali and alkaline earth met als sodium potassium barium etc in their free metallic form Materials become more reactive when finely ground or powdered and in this state magnesium and aluminum may react with compounds containing fluorine especially at higher temperature Highly reactive materials should not be brought into contact with hydrochlorofluorocarbons HCFC or hydrofluorocarbons HFC until a careful study is made and appropriate safety precautions are taken 4 2 2 Compatibility with elastomers Laboratory tests showed that elastomers normally used with R 12 are compatible with the SUVA MP blends Tests also showed no compatibility problems with metals plastics wire insulation and other components normally used in R 12 systems There is considerable variation in the effect of SUVA9 refrigerants on elastomers and rubbers used as O rings in shaft seals and other applications This is because such parts are compounded from the basic polymer together with plasti cizers and other products In laboratory tests
46. d SUS or SSU used in the USA because the method of measurement is different Liquid measure the US gallon 3 785 litres is different from the British or Imperial gallon 4 55 litres Confusion may arise with older equipment the origin of the equipment concerned will usually clarify is meant For smaller liquid measures in both US and Imperial systems 1 gallon 4 quarts 8 pints The decimal point may be written differently in Britain or the United States from other European countries Usage in this manual is shown by these examples 45 millimetres mm 0 045 metres m 2 100 kilogrammes kg 2 1 tonnes t Ton of Refrigeration TR was historically the cooling effect produced by the melting of one American ton 2000 Ib of ice It is now standardised at 12000 Btu h or 200 Btu min and still widely used in the USA 2 2 Basics of refrigeration 2 2 1 Introduction The producing of cold is a heat transfer process which was defined by H W Carrier as follows Refrigeration is the transfer of heat from where it is undesirable to where it does not create a problem The main methods commonly used today are Physical methods a Change of state from solid to liquid i e ice or use of the latent heat of melting b Change of state through compression and expansion by mechanical refrigeration use of latent heat of vaporization c Thermoelectric method Physico chemical methods Method based on absorptio
47. d in a refrigera tion system are Red iron oxide FeO Black iron oxide FeO Red copper oxide CuO Black copper oxide CuO Iron oxides rust is Fe O are most frequently due to the action of air and water When a compressor is opened and dismantled for repair work all internal surfaces must be protected at once with lubricant or grease which is to be removed immediately before reassembly How to deal with contaminants m Copper oxides are usually due to Incorrect brazing tech niques see Chapter 9 Brazing and Soldering m Oxides may react further to produce corrosive metal salts and if water is present this reaction may continue almost indefinitely m Rust will tend to separate from the metal surface as solid particles 6 2 4 Solid particles Most solid particles enter the system as a result of careless preparation and assembly See Paragraph 9 1 below for recommendations on cutting tubing Pipes and components should not be forced into place as this can cause small metal particles to break off Tubing and components such as sight glasses and filter driers are normally supplied with protec tive caps These should be kept in place until immediately before being fitted to prevent dust from entering Fine metallic particles may appear during the running in period of a new compressor Rust as noted above may form in the system Solid particles can block the expansion device and cause wear in the compressor Th
48. d quantity and the lubri cant the service engineer will have to investigate before working on the unit Therefore it is recommended that the system owner keeps a log book or other record close to the unit If the system was previously maintained by a colleague in your own company or by another company in the area you can find out and save time by a phone call before visiting the site Otherwise the pressure will probably tell you and only in a very unusual case will it be necessary to call for a chemical analysis That could happen if through mistakes in the past a mixture of CFC or other refrigerants had been charged 44 Assuming that there is no recycled CFC available and that the system owner decides to retrofit the system rather than replacing the unit by a completely new system there is a choice between two options to be made m Either retrofit the existing unit with a service refrigerant or m Convertthe unit to a HFC refrigerant The service refrigerants generally offer the most cost effective way of retrofitting equipment that has been oper ating on CFCs This is especially true for old equipment 23 5 years A simple decision tree describing the situation is given below DECISION TREE S 3 years How old is the unit Is the system complex large gt 5 years Evaporating temperature SUVA service refrigerants SUVA alternative refrigerants Note FREON 22 is often considered as a retrofit option
49. e However tests have shown that these universal moisture indicators do not always react until the system has been exposed to too high a moisture level Therefore it is advisable to check with the moisture indi cator supplier the performance of a specific indicator 7 4 2 Liquid indicator A liquid indicator in a refrigeration system must be able to give the refrigeration engineer reliable information on whether the moisture level in the installation is or is becom ing too high The acceptable level depends on what effect the moisture content will have on the life of components espe cially the compressor This moisture limit depends on the type of refrigerant the type of oil water solubility in them and special requirements for dryness 29 DuPont SUVA Refrigerents Service Manual Traditionally the dryness requirement was generally met if the moisture content was maintained at a level where the risk of ice formation was eliminated For example in a CFC 12 system this would be a water content of 25 ppm maxi mum at room temperature Maximum moisture levels of 50 ppm are normally recommended in SUVA 134a plant Liquid line moisture indicators situated between the drier and the expansion valve can give other information Bubbles in the sight glass will indicate a problem such as Lack of refrigerant Severe pressure drop through the filter probably due to clogging Lack of pressure in the condenser
50. e cylinder head and discharge valve This is precisely the part of the system that already has the highest temperature A higher temperature is undesirable Generally speaking any chemical reaction pro ceeds twice as fast for every 10 C rise in temperature Thus systems with excessive air or other NCG will be significantly less stable than one that has been properly evacuated There may be a good design reason for operating a com pressor at a high temperature But from the point of view of stability the lower the temperature the better Nitrogen that has been used to protect parts of the system during welding or brazing must be removed afterwards Dry nitrogen is pumped into new compressors before they leave the factory to protect the interior of the compressor from cor rosion This is good practice but the compressor lubricant becomes saturated with nitrogen Nitrogen is practically inert and is therefore less dangerous than air but itis a NCG that resists compression It must be fully evacuated to avoid over heating the compressor 6 2 2 Water It should be noted that water aggravates the effect of other contaminants If a system contains air but is perfectly dry an unlikely situation in practice rust will not form acids and particularly inorganic acids such as hydrochloric and hydrofluoric acids are more corrosive in the presence of moisture than in a dry system 623 Oxides The principal oxides that may be encountere
51. e main protection against solid particles is the metal mesh screen of the filter drier In bad cases this too can become blocked and will need to be changed The compres sor lubricant pump also normally incorporates a filter screen of typically 25 microns 0 025 mm New compressors are also very often fitted with a compressor suction filter When installing the compressor make sure that this filter can be removed easily Some compressor manufacturers recommend that the suc tion filter be removed and discarded after an initial running in period It is probably better practice to replace the filter with a new one or clean and replace the old filter This way the compressor has long term protection against solid particles If the suction filter is retained inspection and cleaning or replacement should be part of the regular maintenance sched ule A blocked filter is better than no filter but it will interfere with the running of the system and may even stop it Itis good practice to change the lubricant after a new open or semi hermetic compressor has run for a short period This is normally covered by the compressor manufacturer s rec ommendations or instructions which should be followed 6 2 5 Other contaminants Although less frequent these are possible causes of trouble Anti freeze agents should never be used because most commercial antifreezes are oxidants and may also be unstable at compressor temperatures Should one of t
52. e of the permanent or New System refrigerant in a retrofit usually to ensure the lowest ODP Retrofitting directly to a SUVA HFC Refrigerant can of course be done but takes longer and costs more than the simple change to a SUVAS Blend 18 Compatibility of SUVA Refrigerants with materials 4 Compatibility of SUVA Refrigerants with materials 4 1 Thermal decomposition SUVA refrigerants will decompose when exposed to high temperatures or to a naked flame Decomposition may produce toxic and irritating compounds such as hydrogen chloride or hydrogene fluoride The decomposition products released will irritate the nose and throat Therefore it is important to prevent decomposition by following DuPont Material Safety Data Sheet MSDS recommendations for handling and use 4 2 Compatibility with materials Because the SUVA refrigerants will be used in many differ ent applications it is important to review materials of construc tion for compatibility when designing new equipment retro fitting existing equipment and preparing storage and handling facilities Since SUVA products have been developed as refrigerants the compatibility data summarised here includes materials commonly used in refrigeration applications 4 2 1 Compatibility with metals Most commonly used construction metals such as steel cast iron brass copper tin lead and aluminium can be used satisfactorily with SUVA refrigerants under normal
53. eason always use a pressure reducing valve or regulating device in the line connecting the nitrogen cylinder to the system 9 4 Fluxes Be sure to use a soldering flux of the correct type Avoid one that contains ammonia since it may have harmful effects when used with copper Always stir the flux before using Some ofthe ingredients may settle to the bottom on standing especially in hot weather for paste types Use a brush to apply the flux not your finger Some of the chemicals in fluxes are very reactive Gently heat the tubing and joint before applying flux if it is in paste form so that it will spread evenly and smoothly Use just the right amount of flux so that a thin film covers the surface of both tubing and fitting Too little flux gives a poor bond and too much is wasteful and makes for a poor looking job Keep the flux well back from the edge of the tub ing at least 5 mm and from the inner end of the fitting 33 DuPont SUVA Refrigerents Service Manual Be sure that no flux gets into the tubing It is one of the worst contaminants in refrigeration equipment As little as 3 g of flux in a 25 kg charge will be insoluble in FREON 22 or SUVA Refrigerants and may cause trouble in the expan sion valve or capillary tubing A recommended practice is to insert the end of the tubing part way into the fitting and then apply the flux to avoid get ting any on the inside Then push the tubing all the way in and rotate t
54. eeded Such monitors are compulsory in most countries for Ammo nia and for R 123 Machine rooms It is probable that they will become a statutory requirement in many countries for all refrigerants in systems above a certain threshold charge size 12 3 2 Pinpointing Pinpointing is undertaken using portable usually hand held leak detectors These are often known as electronic leak detectors The hand held systems usually fall into one of two types m Pumped sniffer or m Detector head The pumped sniffer consists of a small hand held unit which contains the pump and detector A sample of air is drawn in through a flexible tube These systems tend to be more robust and often more sensitive than the detector head systems As against this response times are usually slower because the sample has to travel down the sample tube to the detector In the detector head units the sensor is actually at the tip ofthe flexible nozzle This gives faster response times how ever the sensor capsule is exposed to dirt grease and other contaminants and as a result often suffers from premature failure or loss of sensitivity The capsule should be and usu ally is readily replaceable The hand held detector usually gives an audible warning of a leak sometimes coupled with a simple visual display Many models have an adjustable sensitivity control In addition to refrigerant sensor technologies the follow ing techniques are also w
55. em Although a lubricant separator is often the solution to lubricant circulation problems in large or medium sized systems these point should be borne in mind m A lubricant separator is a pressure vessel subject to the relevant codes and standards it may therefore be a signif icant addition to the cost of the installation m Itisdifficultto clean a lubricant separator after a burn out m Lubricant separators vary in efficiency some lubricant will usually pass through into the circuit The gas veloc ity recommendations of approximately 3 5 m s in hori zontal lines and 7 5 m s in vertical risers should not be dis regarded even if a lubricant separator is fitted m Inalarge system with long piping runs a refrigerant cir culation pump is often fitted Lubricant in the circulating refrigerant will lubricate the pump 5 6 Charging the lubricant 5 6 1 Lubricant and service refrigerants As stated above always consult the compressor OEM or refer to the OEM s technical literature for specific lubricant recommendations and retrofit guidelines for the alternative refrigerant particularly if the system is still under warranty Failure to follow the manufacturer s recommendations could void the warranty of the equipment 23 DuPont SUVA Refrigerents Service Manual 5 6 2 Precautions If lubricant is not handled correctly air and moisture can enter the system either directly or in the lubricant Keep lubricant containe
56. ended m Alength of copper tubing shaped and of suitable diam eter so that when it is inserted through the lubricant filler opening in the compressor the end reaches bottom of the crank case sump m Plastic sealing material m Seal the connecting line and the vacuum line into the top of the receptacle using the plastic sealing material or mastic m Close both service valves to isolate the compressor m Start the vacuum pump By pulling a vacuum in the receptacle this draws the lubricant out of the compressor into the receptacle If as recommended this is a gradu ated glass flask the engineer can check the quantity and colour of the lubricant withdrawn 5 6 7 Alternative method Refrigerant pressure can be used instead of vacuum The same length of shaped copper tubing is used however it is sealed into the lubricant filler opening in the compressor Suf ficient refrigerant vapour is let into the compressor through the suction service valve to create a positive pressure in the crank case This causes the lubricant to flow out into the receptacle This method removes the lubricant less completely than the Recommended Method It is more suitable for taking a small sample of lubricant for analysis 5 6 8 Possible entry of air After removing lubricant by either method there is a danger that air with its associated moisture may have entered the compressor Counter pressure of refrigerant coming out of solution fro
57. ersion Tables are included as an Appendix to this Manual Some remarks may be helpful Temperature according to the SI rules should be expressed in Kelvin K 0 K absolute zero Difference of temperatures is also expressed in Kelvin Use of degrees Centigrade or Celsius C is permitted and is followed in this manual Pressure in SI units is measured in Pascal Pa even for scientific purposes the kiloPascal kPa is used but this Man ual follows general industry practice in using the bar b The bar is close to but not identical to the Atmosphere atm in the former metric system In strict use 1 bar or 100 kPa is the average atmospheric or gauge pressure Zero bar or 0 kPa is an absolute vacuum and there are no minus numbers However most pressure gauges in use are based on zero bar atmospheric pressure which is equivalent to 1 bar absolute 1 standard atmosphere 101 325 kPa American usage makes clear distinction between psia pounds per square inch absolute and psig pounds per square inch gauge If you encounter psi alone without the qualifying or itis normally gauge pressure that is meant this imprecise expression should be reserved for cases where only difference in pressure is referred to Viscosity the SI unit for kinematic viscosity is the Stoke St For convenience the centistoke cSt is used for oil vis cosity There is not an exact numerical conversion to Saybolt Universal Secon
58. es stop it altogether 2 Rusting corrosion lubricant sludging and general deteri oration of the system 3 Water may not contribute directly to refrigerant decom position but the presence of water multiplies the damaging effect of the acids formed in the lubricant refrigerant reaction Note A hydrate is a solid similar in appearance to ice or frost Itis a complex molecule made up of water and refrig erant Hydrates may form at a higher temperature than ice and may remain solid at a temperature at which ice would melt 7 2 How much water is safe There is no safe level and there is general agreement that the less water present the better It should in all cases be below the solubility level see section 7 4 2 Water can enter a system with the refrigerant the lubri cant or with the piping and components Since only the SUVA Refrigerants is under DuPont s control we set the very high standard of 10 parts per million ppm maximum for SUVA Refrigerants shipped from DuPont Approved Reloaders to their customers in the field Refrigeration lubri cant may contain up to 50 ppm water 7 3 Solubility 7 3 1 Solubility of water in liquid refrigerants The solubility of water in HFC refrigerants and blends such as SUVA 134a SUVA HP62 or SUVA 9000 is typically more than 10 times that in CFC refrigerants Due to the risk of hydrolysis when water reacts with POE ester lubricant to form acid the requirement o
59. es of oils for use with their equipment and issue rec ommendations based on their own tests and experience Their advice should always be taken into consideration If the compressor is under warranty when an oil change is made to use an oil not approved by the compressor OEM might invalidate the warranty Even if the compressor is no longer under warranty the advice of the OEM should not be disregarded without good reason 5 2 Miscibility of lubricants and SUVA Refrigerants AB oils and MO are mutually miscible AB oils with SUVA MP Blends can tolerate much more residual MO than POE lubricants with HFC refrigerants Retrofitted systems with AB and SUVA MP39 have operated satisfactorily contain ing 50 MO When the new refrigerant is SUVA 134a and the new lubricant is POE experience indicates that up to 5 or exceptionally 10 of MO can be allowed to remain in the system For evaporating temperatures below 20 5 of MO should be regarded as the maximum 5 3 Residual mineral oil When retrofitting or converting an existing system from CFC 12 or another CFC refrigerant to a SUVA Refrigerant it will be necessary to change the mineral oil to another lubri cant type see above Most of the old oil will be in the com pressor crankcase it can be drained and sent for disposal at the same time as the CFC refrigerant is removed and sent for reclamation However the oil in the refrigeration circuit may be a significant q
60. f clean dry tubing and fittings The way copper tubing is handled is one of the keys to main taining clean dry systems Coils of dehydrated tubing come moisture free and free of all other contaminants They are physically clean as well To maintain cleanliness do three things m Keepoutair and moisture as much as possible m Keep dirt and debris out of the tubing interior m Avoidoxidizing the copper metal when making soldered or brazed connections Follow recommendations outlined in Chapter Brazing and soldering Tips on handling tubing Schedule work Don t cut into a new copper coil near the end of the day However if necessary m Usealllengths cut from the coil and reseal the remaining lengths m Sealall openings in the system when leaving the job for any length of time Hard drawn copper tubing or pipe The same comments apply to copper pipe Use only pipe or hard drawn tubing that has been cleaned and capped by the manufacturer Reseal tubing if itis not used immediately Use great care in handling to keep the tubing as clean and dry as when it is purchased Factory handling of condensing units and coils Manufacturers of air conditioning and refrigeration equip ment insist on rigid cleaning dehydration and evacuation practices as part of their standard quality control Quality control personnel not only examine incoming semi finished parts and supplies but they are charged with the responsibil ity of excludin
61. f low humidity in a HFC POE system must be complied with Nevertheless water is less soluble in some refrigerants than in others If more water is present it will exist as a separate liquid water phase or if the temperature is low enough as ice or hydrate 7 3 2 Solubility of refrigerant in water In all cases the solubility of fluorinated refrigerants in water is quite low and ordinarily is of little concern in operating systems However in some applications there is a possibility of refrigerant coming into contact with water through equip ment failure in heat pump or refrigeration condensers water chillers drinking fountains etc If this happens the amount of refrigerant that might dissolve in the water may be significant and the contaminated water should not be dischanged without treatment Because water may be present in the valve fittings and the charging line it is good practice to pass the refrigerant through a drier when charging 7 4 Moisture indicator 7 4 1 Sight glass indicator The moisture indicator is a sight glass containing an element cobalt salt which reacts with the moisture contained in the refrigerant Exposed to moisture this chemical changes its colour normally from pink to blue Moisture indicators for HFCs are different from indi cators Ensure that your component supplier provides the appro priate indicator type It will normally react by changing colour at about 30 to 75 ppm moistur
62. f very low toxicity Every effort must be made to avoid leakage from systems and systems must be reliable Dismantling and opening up systems for maintenance must be reduced to a minimum This demands a high level of skill and pro fessionalism from refrigeration technicians The purpose of this Manual is to assist those who work directly with both new and existing refrigeration and air conditioning systems to achieve with SUVA refrigerants the highest levels of personal qualification and performance That is needed more than ever today Table of Contents 1 1 1 1 1 1 1 2 1 1 3 114 1 1 5 1 1 6 1 1 7 1 2 1 2 1 1 2 2 2 1 22 221 2 2 2 2 3 2 4 2 3 2 6 3 1 3 2 4 1 4 2 4 2 1 4 2 2 4 2 3 Foreword Introduction The ozone layer Historical backeround What is the ozone layer Ozone depletion Ozone depletion potential Current state of the science Other theories The future of the ozone layer Global warming The global warming issue The tewi Background information Units Basics of refrigeration Introduction Fundamentals Definitions of types of fluorocarbons Single component refrigerants and azeotropes Non azeotropic refrigerants The practical implications of using non azeotropic refrigerants DuPont SUVA Refrigerants The range of DuPont SUVA refrigerants Selection of DuPont refrigerants Compatibility of SUVA Refrigerants with Materials Thermal decomposition Compatibility with mater
63. g all contaminants from the finished product 31 DuPont SUVA Refrigerents Service Manual 32 Refrigerants and lubricants for example are analyzed regularly to make sure that rigid quality specifications are met Hermetic motors are degreased to remove all traces of unstable lubricants and solvents and are dehydrated to the point where insulating materials can no longer give up moisture All compressor parts including hermetic shells are cleaned and considerable precaution is exercised to prevent rusting before final assembly Finished condensers and evaporators are cleaned and dehydrated and either assembled into complete systems or sealed until used at some future date This care in handling should be continued through every step of installation and servicing in the field if systems are to do the job they were designed to do Brazing and soldering 9 Brazing and soldering Brazing flux and other materials used in the joining of refrigerant lines can be a major source of contamination so good brazing technique is critical The method of heat application can either increase or minimize the amount of brazing contaminants in a system To ensure leak light systems good practice and in many countries environmental regulations require the use of brazed joints Flare joints should not be used Where a component has to be removed for maintenance compression joints should be used 9 1 Preparation of tubing If it i
64. harge to use will vary widely from system to system This makes it doubly important always to check the name plate 11 3 Check manufacturers catalogues Catalogues and service bulletins are available from equipment suppliers and air conditioning and refrigeration distributors and wholesalers Keep them on file and study them before charging a system Liquid receiver capacities for most con densing units and for complete systems supplied by manu facturers for field erection can be found in the bulletins 11 4 Vapour charging Do not charge SUVA blends vapour phase This means that the refrigerant should be remove from the cylinder as a liquid either from the dip tube in a two value cylinder or by inverting the cylinder The liquid is allowed to evaporate flash in the charging lines Small systems with a single component refrigerant such as SUVA 134a are usually charged through the gauge port of the compressor suction service valve Normal procedure is 38 1 Back seat suction service valve as for normal operation 2 Loosely connect line from from service manifold to suc tion service valve gauge port 3 Connect centre line from manifold to the refrigerant cyl inder 4 Back seat discharge service valve 5 Loosely connect remaining line from service manifold to discharge sevice valve gauge port 6 Slightly open cylider valve to purge vapour up to the com pressor discharge service valve 7 Tighten discharge
65. harging lubricant makes sure that no air or moisture will enter the system There will be a small loss of refrigerant which may need to be replaced Be careful not to empty the lubricant container com pletely as this will pump air into the compressor If this does happen replace the lubricant filler plug and pull a complete vacuum Small quantities of lubricant to top up the lubricant charge can be added using a lubricant syringe Air will not enter the system during the short time that the lubricant filler plug is open because refrigerant dissolved in the lubricant in the compressor crank case will maintain the necessary slight positive pressure as it comes out of solution If alubricant pump is available it should be used A well designed lubricant pump can fill lubricant in measured quan tity against the pressure in the compressor crank case Lubricants and their relationship with SUVA Refrigerants 5 6 5 Draining lubricant Draining lubricant is necessary m Whenchanging from CFC to SUVA Refrigerant requires removing the major part of the Mineral Lubricant m If the lubricant has degraded and become acid during service m Aftera burn out If there is any doubt that the clean up was not completely successful 5 6 6 Recommended method Equipment required m Vacuum pump m Connecting line m Receptacle for lubricant to be removed an old lubricant container can be used but a graduated glass flask is rec omm
66. has been identified as the destructive element that reacts with ozone to convert it to nor mal oxygen and because this happens over and over again a catalytic chain reaction a single atom of chlorine can destroy several thousand molecules of ozone Bromine is even more damaging than chlorine Chlorine released by itself at the Earth s surface does not affect the Ozone Layer because it reacts with other elements to form various more or less unstable compounds that are diluted and rained out of the lower atmosphere or tropo sphere Chlorine locked into the very stable CFC molecule does not react until it reaches the stratosphere There the CFC molecule breaks down releasing chlorine where it can react with the ozone molecules in the Ozone Layer The HCFC molecule is much less stable in the tropo sphere than a CFC molecule although it may be very stable in refrigeration use so that the major part of HCFCs released break down before reaching the Ozone Layer in the strato sphere 1 1 4 Ozone depletion potential Ozone depletion potential ODP is the calculated amount of ozone depletion caused by the release of a given quantity say 1 kg of the compound concerned compared to the depletion effect of the same mass of CFC 11 The calcula tion takes into account all the potential effects on strato spheric ozone of the specified compound during the whole time that traces of the compound could remain in the atmos phere the t
67. he fitting or tubing a few times if possible to spread the flux evenly over the area It is also important to support the assembly so there is no strain on the joint during soldering or cooling 9 5 Applying heat Heat the joint as evenly as possible by directing the torch at the bottom of the fitting socket and at the tubing alternately If one part has a greater mass than the other it will require more heating time Avoid letting the flame touch the seam where the solder will be applied because it can burn the flux From time to time while heating touch with the solder to see if the metal is hot enough to melt it Be careful not to overheat High tem peratures can decompose the flux and affect the solder Heat only enough to melt the solder In some cases it may not be possible to apply the flux before assembling the joint If so put a moderate amount of flux on the tube near the joint and warm slightly Then heat the fitting evenly till the flux melts and is drawn into the joint 9 6 Applying solder 9 6 1 Melting solder When the tubes and fittings are hot enough to melt the solder touch the tube joint with the solder wire at several places Capillary action will draw the molten solder into the joint and around the tube Then a ring of solder appears all around the tube the job is finished and a good leak proof joint has been made To make a neat appearing joint in soft solder joints wipe the tube with a cloth while the solder
68. he method of drying be sure to add a liq uid line drier if it is at all possible Even though the system has been carefully dried it is quite likely and even possible that some additional water may enter during the charging of the refrigerant and the lubricant Furthermore as time goes on water may be extracted from various components of the system and may even be formed by the reaction between air and some of the materials present Driers also tend to scav enge decomposition products and to filter out other contam inants in the system 7 6 Function of the filter drier The filter drier has three main functions To adsorb moisture which despite precautions may have remained in the circuit or may be introduced with the refrig erant or lubricant The presence of water makes the system less stable and may cause ice formation in the expansion valve or in the evaporator The second function is to neutralise acids that may evolve in the system These acids may damage the electric motors of hermetic or semi hermetic compressors and may cause copper plating and other problems in all types of compressors An additional function is to retain solid particles and prevent them from reaching and damaging the compres sor A metal mesh filter is normally incorporated for this purpose How to keep systems clean and dry 8 How to keep systems clean and dry 8 1 Cleanliness and SUVA Refrigerants Here are some tips on good handling p
69. hese products have been added to a system this is one of the rare cases other than a burn out where a complete change of the refrigerant and lubricant is justified Soldering flux is usually reactive causing corrosion and also virtually insoluble in SUVA refrigerants Use the tech niques outlined in Chapter 9 to prevent flux from entering the system Once in a system flux is very difficult to remove It may be necessary to replace a blocked component such as a filter drier Solvents such as perchlorethylene and trichlorethy lene may have been used as degreasing agents in the manu facture of components Good quality components from rep utable manufacturers do not contain any residual solvent Thorough evacuation before charging will remove solvents along with other volatile contaminants Chlorinated solvents are not recommended and can decompose at high tempera tures to produce hydrochloric acid 6 3 Evacuation 6 3 1 Purpose of evacuating a system before charging The purpose of evacuating a system before charging is m To remove air m To remove moisture m Toremove any gas that may be dissolved in the compres sor lubricant if the compressor is charged with lubricant 6 3 2 Method of evacuation The method of evacuation chosen and the time taken will depend on Size or internal volume of the system Amount of liquid water present in the system Capacity of the vacuum pump Length and diameter of the connect
70. ials Compatibility with metals Compatibility with elastomers Compatibility with plastics page O00 OO 10 10 10 10 10 14 15 16 17 18 18 19 19 19 19 19 19 5 1 9 2 2 9 54 9 3 5 5 1 5 5 2 5 5 3 5 5 4 5 6 5 6 1 5 6 2 5 6 3 5 6 4 5 6 5 5 6 6 5 6 7 5 6 8 6 1 6 2 6 2 1 6 2 2 62 3 6 2 4 6 2 5 6 3 6 3 1 6 3 2 6 3 3 6 3 4 6 3 5 6 3 6 6 3 7 6 4 7 1 7 2 7 3 7 3 1 page Lubricants and their behaviour with SUVA Refrigerants 21 Lubricants for use with SUVA refrigerants 21 Residual mineral oil 21 Miscibility of lubricants and SUVA refrigerants 21 Lubricant quality 22 Lubricant viscosity 22 Standard viscosity 22 Viscosity in a refrigeration system 22 Lubricant circulation Oil return to the compressor 23 Lubricant separator 23 Charging and changing lubricants 23 Lubricant and service refrigerants 23 Precautions 23 Charging the lubricant 24 Normal lubricant charging procedure 24 Draining lubricant 24 Recommended method 25 Alternative method 25 Possible entry of air 25 How to deal with contaminants 26 Importance of keeping system free of contaminants 26 The principal contaminants 26 Air 26 Water 26 Oxides 26 Solid particles 27 Other contaminants 27 Evacuation 27 Purpose of evacuating a system Before charging 27 Method of evacuation 27 Water present as vapour 28 Accurate vacuum at low levels 28 Evacuation meth
71. idely used in pinpointing leaks in refrigeration systems m Soap bubbles in fact usually liquid detergent generally used only during system assembly installation This is a simple moderately sensitive method of finding leaks m System additives A fluorescent dye is the basis of an additive system marketed under several trade names The dye is soluble in the refrigeration compressor lubricant and leaks out wherever there is a refrigerant leak The dye becomes visible as a bright yellow green stain under UV light Leak detection m Battery or mains powered hand held UV lamps are supplied as part of the additive system The dye is easy to clean away after the leak has been repaired It is impor tant to confirm that equipment warranties will not be voided by the addition of such dyes to the system Halogen Torch The flame of the torch changes colour but only in reaction to chlorine containing substances it will detect CFCs and HCFCs but will not detect HFCs SUVA 134a SUVA 404A SUVA 407C etc It has several limitations for example it is difficult to use in windy or drafty places and it may be a safety hazard The halogen torch is being made obsolete by the modern electronic hand held leak detectors 43 DuPont SUVA Refrigerents Service Manual 13 Retrofitting existing systems 13 1 Conversion of existing systems from CFC to non CFC refrigerants As explained in chapter 1 above CFC refrigerants are not pe
72. ies are used Some are more sensitive to chlorine containing compounds than to HFCs The most suitable show similar sensitivity to all halogens m Compound specific these detectors are designed to measure concentrations of one specified refrigerant in the presence of other refrigerants Such detectors are generally only available as fixed units but portable units are beginning to become available They generally incor porate an infra red spectrophotometer which can be tuned to select a specific absorption frequency which is characteristic of the compound desired 12 3 1 Leak detection Leak detection is usually carried out by means of a fixed unit known as a leak monitor which has fixed sampling points at specific locations These either draw samples of air sequen tially through an analysing unit or the Monitor has remote sensor units placed at selected locations The unit is pro grammed to give an alarm signal if a leak occurs The alarm signal can be local or remote it is common practice for super market systems to send the alarm signal through a modem link to a service contractor s premises Many systems have data storage capability to allow sophisticated analysis of refrigeration system losses over time 42 Leak monitors also fulfil an important Occupational Health and Safety role by routinely analysing the air in occu pied enclosed spaces such as machine rooms and warning when and where acceptable exposure levels are exc
73. ing lines Presence or absence of lubricant 27 DuPont SUVA Refrigerents Service Manual 6 3 3 Water present as vapour Water present only as vapour will be removed with the air therefore is not a problem Liquid water must evaporate and become vapour before it can be removed The boiling point of water which is 100 C at normal atmospheric pressure 1 013 bar becomes lower at lower pressures For most effective moisture removal it is therefore neces sary to warm the system this must be done gently with a heat lamp or a warm air electric heater Never use a welding torch as this could damage a part of the system Note Evacuation is not effective at removing moisture dissolved in POE or PAG oils see 7 6 6 3 4 Accurate vacuum at low levels For reading the vacuum accurately at low levels a thermo couple vacuum gauge is necessary The ordinary compound vacuum gauge is only accurate down to about 50 Torr This is not sufficient for effective deep evacuation To determine that evacuation is complete close the valve between the vacuum pump and the system Wait five minutes for the slight rise in pressure due to flow ceasing Read the pressure After 30 minutes or longer if possible on a large system read the pressure again If there has been no rise in pressure the system is ready for charging 6 3 5 Evacuation methods Deep evacuation in one step to 0 05 0 1 Torr is the most reli able method but it takes
74. inthe system Recovery and reclaim or disposal is the best course of action provided that a suitable service exists reasonably close to the site Care must be taken not to overfill the cylinders or other containers used to transport the recovered refrigerant because of the hazard of such a container becom ing liquid full In most countries there are dedicated containers that can be obtained from Authorized distributors To leave the refrigerant in the system is possible only in the case of a large quantity and a burn out that has not spread Motor burn outs far through the system The system must incorporate iso lating valves and a sufficiently large receiver because of the next steps to be taken Discharge out of doors has been current practice in the past This practice is no longer permitted by law The refrigerant should therefore not be vented to the open air but instead should be recovered for further reclamation or for destruction Refrigerant from a burned out system must never be dis charged 10 5 Clean up 10 5 1 No significant quantities of carbon and other debris If no significant quantities of carbon and other debris have spread through the system and particularly if the lubricant is not seriously acid acid number less than 0 05 ppm no spe cial steps are necessary Itis sufficient to replace the compressor and to replace the filter drier with a new one The new filter drier should be one size larger th
75. ixture of different desiccants are compatible with SUVA HP refrigerants Consult your filter drier supplier Refrigerant Since SUVA HP80 and SUVA HP81 are both semi azeotropes near azeotropic mixtures it is essential to charge them exclusively in liquid phase For most installations the SUVA HP charge will be 90 47 DuPont SUVA Refrigerents Service Manual to 95 of the previous R 502 charge by weight Other components Generally it is not necessary to change the Expansion Device Pressure Gauges or other components of the system For lubricant see paragraph 13 4 2 above For moisture indicating sight glasses see chapter 7 above 13 4 4 Equipment required for conversion General consideration Use the recovery cylinders provided by your SUVA Refrigerant supplier Indicate clearly the refrigerant you want to recover when ordering the recovering cylinders to ensure that you use appropriate cylinders m Do not over fill cylinders m Donotmix refrigerants Equipment required m Personal safety equipment eye protection gloves m Recovery Unit to withdraw the R 502 as completely as possible from the installation and to minimise CFC emissions to the atmosphere m Scale to weigh the R 502 withdrawn and ensure correct weight of the SUVA HP charge m Recovery Cylinder one or more m Vacuum Pump of adequate capacity and whose perfor mance has been checked regularly with a vacuum gauge m Ref
76. l continuity confirms a burn out without further investiga tion Take care not to burn out the thermistor if fitted while testing Take a sample of lubricant from the compressor Dark colour and an acidic reading by an Acid Test Kit is an indi cation of a burnout when the compressor will not start If the compressor has been installed with isolating valves in accordance with recent recommendations these should be closed Refrigerant from the compressor itself should be vented out of doors using a suitable line Opportunity should be taken to catch lubricant droplets from each valve on a clean white paper or cloth and inspect for cleanliness or alternatively the presence of carbon or other debris It is normal to find carbon only on the suction side because the suction port is in most compressors directly connected to the motor If the burn out occurred when the compressor was stationary the high pressure side is usually clean However if the compressor continued to run during a slow burn out both sides will be contaminated with car bon and acidic sludge from the lubricant At this stage enough information should be available to decide how much of the system has been affected by the burn out It should not be necessary to cut any of the lines to inspect for the presence of carbon 10 4 What to do with the refrigerant There are two alternatives m Recover it and send it to be reclaimed or disposed of m Leaveit
77. liquid line or to malfunction or partial blockage of the expansion valve Consequences can be serious for example freezing of food that should not be frozen or icing up of an air conditioning system evaporator 3 Compressor short cycling stopping and re starting more frequently than is normal for the size and type of compressor More than about 12 times per hour would generally be regarded as excessive Short cycling may also be due to mal function or incorrect setting of the compressor controls 4 Compressor over heating in this case due to insufficient refrigerant flow to cool the compressor This as in the case above may be due to an obstruction elsewhere in the circuit 5 Compressor running continuously due to loss of cooling capacity There is not enough refrigerant in the circuit to achieve the required performance 6 Low liquid level in the receiver in a system with a sight glass in the liquid receiver and provided that the normal level is known this is the most reliable indication of loss of refrigerant charge As will be seen from the examples above the symptoms of loss of refrigerant charge are not clear This emphasises the advantages of a positive method of identifying leaks It is better not to wait for leaks to appear but to inspect for them on a regular basis On large systems where continuous reliable operation is critical leak inspection should be made on a regular weekly schedule 12 3 Methods
78. liquid phase They boil and also condense at one constant temperature for a given pres sure and have a simple Pressure Enthalpy chart The original FREON refrigerants such as R 11 R 12 and R 502 belong to this group as do some of the new SUVA refrigerants for example SUVA 123 and SUVA 134a Pressure Subcooled Superheated liquid vapor i i region _ Constant temperature 1 z Liquid vapor Saturated vapor line Enthalpy 2 5 Non Azeotropic Refrigerants The Non Azeotropic Refrigerants which interest us are blends which behave to a limited extent in a similar way to true azeotropes For this reason they are generally referred to as non azeotropic refrigerants or sometimes as NARMs which stands for Near Azeotropic Refrigerant Mixtures or fluids All the refrigerants of the ASHRAE R 400 series are included in this group These include SUVA MP39 R 401A SUVA MP66 R401B SUVA HP80 R 402A SUVA HP81 R 402B SUVA R 404A SUVA R 407C and SUVA R 410A DuPont SUVA Refrigerents Service Manual For these refrigerants the composition of the saturated vapour is different from that of the saturated liquid Fig 12 This means that as evaporation proceeds as the vapour quality increases in the evaporator the composition of the boiling liquid changes This change in composition is asso ciated with a change an increase in boiling point temper ature at the given pressure Thus
79. llary tube system is also the simplest provided that no refrigerant is discharged to atmosphere 1 Withdraw all refrigerant remaining in the system Recover it for reclamation 2 Then recharge on a weight basis 3 Use the amount of SUVA refrigerant specified by the manufacturer on the name plate or in his service bulletin There are other methods by which you can add refrigerant to make up a complete charge They involve checking the pressure and temperature conditions at various parts of the system as outlined This extra work usually takes more time and gives very little in return so that in most cases on such small systems it pays to replace the charge completely Leak detection 12 Leak detection With the increasing focus on refrigerant containment both from cost and environmental considerations it is becoming ever more important to ensure that refrigeration systems are leak free when installed and that if leaks develop during oper ation these are rapidly corrected 12 1 Designing to reduce leaks Leaks may occur in refrigeration air conditioning heat pump and heat recovery systems for a variety of reasons The fre quency of leaks may be reduced by good workmanship and care in assembling new installations The following points deserve attention m Good brazing and soldering techniques m Brazing in preference to screw connections m Compression screwed connections in preference to flared connections N
80. longest Triple evacuation is often used because it is quick and does not require a special vacuum gauge The system is evac uated to 50 Torr then the vacuum is broken with dry oxygen free nitrogen OFN until it is at atmospheric pressure This operation is repeated When the system is evacuated for the third time it is ready for charging after checking that there has been no rise in pressure Break vacuum this time with SUVA refrigerants This method has two disadvantages It will not remove liquid water and it causes wasteful emissions of fluorocar bon refrigerant One purge evacuation to 1 2 Torr is a compromise between the other two methods Evacuate the system to approximately 2 Torr 28 6 3 6 Capacity of the vacuum pump Capacity of the vacuum pump must be sufficient for the inter nal volume of the system Typically a pump of 90 l min is recommended for a system of 7 8 kW Of greater importance than pump capacity is the length and diameter of the connecting lines For example evacua tion through a 1 4 inch 6 35 mm line will take 8 times longer than through a 1 2 inch 12 7 mm line Evacuation by aline 2 m long will take twice as long as through a 1 m line Two lines are recommended to evacuate the high side and low side simultaneously 6 3 7 Ouantity of liquid water If any significant quantity of liquid water is present cold trap is valuable as it serves to protect the lubricant in the vac uum pump fro
81. ls than do the CFC refrigerants extensive field experience has shown that in practice in many situations these new refrigerants do perform reliably when using mineral oils Synthetic oils are now available that have been tested extensively with SUVA Refrigerants The three types that are now most used are Alkyl Benzene AB oils have been used in the refrigera tion industry for over 25 years selected for high miscibility with HCFC refrigerants and with CFCs and for excellent thermal stability They are currently used in many low temperature applications when CFCs or R 22 is used AB oils are only used in specific applications with HFCs Polyester POE lubricants are particularly recommended for most applications with HFCs The basic product can be tailored for optimum performance in specific equip ment or applications POE lubricants are first choice with SUVA 134a SUVA 407C SUVA 410A or SUVA 404A POE lubricants will absorb moisture from the air and should be handled carefully Polyalkylene Glycol PAG lubricants are widely used in mobile applications such as automobile air conditioning with SUVA 134a PAGs have a strong affinity for water and are particularly liable to pick up moisture from the atmosphere therefore care in handling is essential POE lubricants also absorb atmospheric moisture and should be handled so as to minimise exposure to air Compressor manufacturers carry out extensive test pro gramm
82. lubri cant removed then place it in an appropriate recipient to be disposed of in accordance with the regulations in force Your SUVA Refrigerant supplier can advise you 6 Charge the new lubricant into the compressor the same volume as removed in the previous step 46 7 Replace the filter drier by one compatible with SUVA MP39 or SUVA MP66 8 Pull vacuum on the entire system Follow normal proce dure to eliminate air and other non condensible gases from the circuit 3 to 5 mbar 9 Charge the installation with the SUVA MP refrigerant exclusively in liquid phase to 75 by weight of the previous R 12 charge The optimum system charge will depend on the operating conditions of the installation and its design For most installations the appropriate charge will be between 75 and 90 of the R 12 weight 10 Re start the system and allow the system to reach stable operating conditions 11 Optimise the performance of the system by completing the SUVA MP charge still in iquid phase through the com pressor suction port until the same operating conditions are reached as recorded with CFC 12 return gas temperature subcooled temperature Make use also of the liquid line sight glass and of the pressure gauges when completing the refrigerant charge Note Do not overcharge the system By controlling liquid subcool ing and vapor superheat you make sure that the system is properly charged When the system is operating
83. m moisture This moisture may reduce the capacity of the pump to achieve the lower pressures recom mended Such a trap can be easily fabricated from material avail able in most shops All welded joints should be vacuum tight 6 4 Disposal of contaminated refrigerant In many cases contaminated refrigerant can be recovered using special equipment built for this purpose Refrigerant that is partially decomposed or very heavily contaminated cannot usually be reclaimed Attempting to do so may result in damage by corrosion to the reclaimer unit and to the cylinders used for transporting the refrigerant to the reclaimer Heavily contaminated or decomposed refrigerant must never be discharged either indoors or outside buildings This is prohibited by law in most countries Decomposed refrigerant may contain toxic breakdown products and present a safety hazard Contaminated refrigerants must be eliminated in special incineration plants Consult your SUVA distributor on how to have this waste collected for destruction Old refrigeration lubricant can be disposed of by burning it Almost all countries have incineration stations where this work can be done Water and Drying 7 Water and drying 7 1 Why worry about water Too much water in a refrigeration system may lead to the fol lowing effects 1 The formation of ice or hydrate in the expansion valve or capillary tube may restrict the flow of refrigerant or in severe cas
84. m the lubricant will certainly limit the entry of air but may not keep it out altogether Before starting to charge fresh lubricant flush any air out of the compressor by opening the suction service valve Quickly screw in the lubricant filler plug then close the valve Most air and air borne moisture will be driven out through the lubricant filler opening If the compressor has been open to atmosphere for any length of time and particularly if solvent has been used to flush out polymerised lubricant or sludge pull a complete vacuum on the compressor before charging fresh lubricant The purpose of this work is to get clean moisture free lubri cant into an uncontaminated system 25 DuPont SUVA Refrigerents Service Manual 6 How to deal with contaminants 6 1 Importance of keeping system free of contaminants Almost all system breakdowns can be traced back to the pres ence of some undesirable contaminant Systems today oper ate at high temperatures with fast running compressors and close tolerances Total system cleanliness must be the aim of every installation engineer It is equally necessary that the field service engineer called in to repair or replace a compo nent does not spoil his good work by introducing contami nants that will cause trouble later It must be remembered that a refrigeration or air condi tioning system is a closed circuit Once a contaminant enters the system it will stay there only action by
85. mal 8 hour work day and 40 hour work week to which nearly all workers may be exposed day after day without adverse effect For most of the chemicals examined including the FREON compounds some expo sure above the TLV TWA is permitted if compensated for by an equivalent exposure below the TLV TWA limit during the rest of the day this is defined as the short term exposure limit STEL In other cases a Ceiling TLV C is defined the con centration that should not be exceeded even instantaneously The highest TLV TWA value assigned to any chemical except carbon dioxide is 1 000 ppm by volume The TLVs laid down by ACGIH are generally accepted by the responsible authorities in other countries but there may be specific exceptions The following SUVA compounds have been evaluated and given the 1 000 ppm rating SUVA 134a 124 125 MP39 MP66 HP80 HP81 404A 407C 410A SUVA 95 14 1 4 Handling precautions Avoid excessive concentration of SUVA refrigerant vapour Vapours are heavier than air and can accumulate in low places Workplaces should have adequate ventilation If it is necessary to discharge significant quantities of SUVA vapour this should be done out of doors The maximum allowable workplace concentration TLV normally 1 000 ppm should be observed Do not inhale concentrated SUVA vapour or swallow liquid SUVA refrigerant for any reason Keep away from flames and hot metal surfaces SUVA vapour ca
86. meters above the Earth s surface This ozone is formed naturally by the action of sunlight on normal oxygen O Ozone is continually being formed and destroyed by chemical reactions which take place naturally in the stratosphere There are large nat ural changes in the concentration of ozone in the layer for example a change of about 25 between summer and win ter over most of Europe The importance of the Ozone Layer is that it filters out a certain amount of the ultra violet radiation that would oth erwise reach the surface of the Earth The part of this radia tion with a wavelength of between 280 and 320 nanometers is classed as UV B radiation There is also UV A which appears to be harmless and UV C which is very harmful but fortunately occurs in only very small amounts A signif icant increase in UV B radiation would have adverse dam aging effects on human beings animals and plants Life evi dently grew up on this planet with this filter in place a reduction or depletion of the Ozone Layer would have seri ous consequences These would include damage to crops and water life and an increase in cataracts in humans and animals and of certain types of skin cancer in humans 1 123 Ozone depletion Ozone depletion is the name for what occurs when the rate of ozone destruction increases due to human activities to the point where the rate of destruction exceeds the natural rate of formation of ozone Chlorine
87. mospheric lifetime Compar ison with CFC 1 1 which has a finite lifetime in the atmosphere of 55 years is practical This is designated a Halocarbon GWP HGWP GWPs are frequently quoted for specific time peri ods Integration Time Horizons or ITH These are gener ally 20 100 and 500 years GWPs referred to in the literature are usually for an ITH of 100 years unless otherwise stated In addition to carbon dioxide and the various fluorocar bons significant greenhouse gases include methane and ozone in the troposphere 1 2 2 Total global warming impact or TEWI is a systems approach to measuring the environmental impact as global warming of a compound as used in our case as a refrigerant TEWI takes into account the direct effect of the emitted refrigerant assuming that it is emitted through its GWP and the indirect warming effect of the carbon dioxide emissions due to the energy required to operate the system over its expected lifetime For a typical modern refrigeration system indirect global warming typically accounts for over 90 of the TEWI DuPont SUVA Refrigerents Service Manual 2 Background information 2 1 Units Use of the International System of Units is obligatory in Europe The system has not been adopted in the USA and in practice many reference books and specifications are still used that give vital information in either the British Ameri can or old metric systems Conv
88. n and adsorption of certain media 222 Fundamentals By comparison with water refrigeration is based on the fol lowing basic principles Fusion In order to change from solid to liquid at a constant tempe rature of 0 C ice absorbs an energy equal to 334 4 kJ kg 80 kcal kg This heat taken from the product to be cooled is called the latent heat of fusion Boiling point This temperature corresponds to the beginning of the change of state from liquid to vapour This temperature is a function of the pressure above the liquid surface A given boiling tem perature corresponds to each pressure Boiling point of water Pressure bar absolute 151 5 100 1 68 0 3 12 7 0 015 6 7 0 010 Latent heat of vaporization To change from liquid to vapour at 100 C constant tem perature at 1 013 bar 760 mmHg standard atmospheric Background information pressure water requires an energy input of 2254 69 kJ 539 4 kcal kg Note that standard atmospheric pressure is 1 01325 bar Superheat If after having obtained saturated vapour further energy is supplied to raise the vapour temperature the vapour will change from saturated to superheated Condensation Changing from liquid to gas is a reversible phenomenon If we remove heat from the vapour it will be changed into water In the above example by giving away heat to ambient air water vapour will change from its gaseous state to liquid between A and
89. n decompose at high temperatures to give toxic products Warning of this is given by irritating acidic decom position products If these occur evacuate the area and venti late thoroughly Do not weld and braze when SUVA refrigerant vapours are present Do not place gas or electric heaters in places where SUVA vapours are expected It is advisable not to smoke in presence of SUVA refrigerant vapour If it is necessary to enter an area containing a high concen tration of refrigerant vapour or of decomposition products of Safety SUVA refrigerants wear a full face breathing apparatus with independent air supply Filter masks are not recommended Protect hands and skin from contact with liquid SUVA Refrigerants which can cause frostbite SU VA 123 does not cause frostbite but removes natural greases from the skin This makes the skin vulnerable to infection Wear gloves when handling SUVA refrigerants Protect eyes from splashing with liquid SUVA refrigerant Wear eye protection Do not over heat cylinders They may be warmed to assist in transferring SUVA refrigerants but never above 50 C Lower temperatures are specified in some countries Use a bucket of warm water an electrical blanket or a heated cup board in each case fitted with a control thermostat never a welding torch Localized heating can weaken a cylinder so that it is no longer safe under normal pressure Overheating may lead to a liquid full cylinder
90. ne atom is now known to be more damaging to the ozone layer than the chlo rine atom Refrigerant fluids are identified by a number based on the original fluorocarbon numbering system developed by Du Pont in the 1930s and adopted world wide since then Defi nitions are issued by ASHRAE the IIR and national stan dards authorities such as DIN and BSI The prefix R for Refrigerant frequently replaces the letters used above For example R 134a is the same as HFC 134a Numbers in the R 500 series such as R 502 denote aze otropes The R 400 series refrigerants are non azeotropes very occasionally called zeotropes blends or NARMs see below These numbers are allocated by ASHRAE and do not describe the chemical composition of the refrigerants Several non fluorocarbon fluids are used as refrigerants They are often called not in kind NIK and are given a designation These refrigerants often have significant safety implications HC hydrocarbon Contains only carbon and hydrogen and is consequently highly flammable and explosive Examples are HC 290 propane C3Hg and HC 600 butane R 700 series denotes inorganic refrigerants for exam ple R 717 ammonia NH Ammonia is flammable and is very toxic 2 4 Single component refrigerants and azeotropes Both single component refrigerants and true azeotropes behave in the same way Fig 11 The saturated vapour phase has the same composition as the
91. ng existing systems SUVA HP 81 is below 35 C see Note in paragraph 13 4 1 13 Adjust the high pressure and low pressure safety cut outs 14 Carry out complete leak check 15 Replace the R 502 sticker by a SUVA HP80 or SUVA HP81 sticker as appropriate On the same or a sep arate sticker record the type and viscosity of the lubricant 16 Make a complete report on the new operating parameters of the system using the retrofit report Note Any welding or brazing operation for example to change the filter drier must be carried out in an inert nitrogen atmos phere to avoid any danger of carbon or copper oxide build up 49 DuPont SUVA Refrigerents Service Manual 14 Safety 14 1 Safe handling of SUVA HP refrigerants and environmental effects 14 1 1 Introduction SUVA refrigerants have been developed to replace FREON refrigerants that have been used for over 50 years They were originally introduced to replace non fluorocarbon refriger ants that were flammable dangerously toxic or both ALL FREON and SUVA refrigerants are Practically non flammable and non explosive Of very low toxicity Non corrosive under normal conditions These properties apply to SUVA refrigerants under nor mal correct conditions of use It is necessary to understand the properties of SUVA refrigerants and to observe the pre cautions listed below 14 1 2 Properties Pressure
92. ng port is located on the liquid line downstream from the receiver In this case refrigerant can be added while the system is not operating General suggestions will not always apply to specific operations but the following outline may be helpful 11 5 1 Connect the refrigerant cylinder to the charging port Connect the refrigerant cylinder to the charging port Use as short a line as possible to minimize water contamination or use a drier if indicated by conditions The cylinder should be upside down if it does not have a liquid vapour valve Install a pressure gauge so that the compressor discharge pressure can be observed 11 5 2 Crack cylinder valve and purge charging line With the connection to the charging port loose crack cylinder valve and purge charging line with refrigerant using the VAPOUR hand wheel of a cylinder fitted with a liquid vapour valve Tighten connection open cylinder valve and check for leaks 11 5 3 Close the valve at the receiver outlet Close the valve at the receiver outlet or if there is no receiver close the valve in the liquid line upstream from the charging port This is necessary to prevent the condensing pressure from forcing liquid into the cylinder 11 5 4 Slowly open the charging port valve and charge liquid With the compressor running slowly open the charging port valve and charge liquid using the LIQUID hand wheel at a rate fast enough to keep the compressor from cutting out on low
93. o be disposed of in accordance with the regulations in force 6 Charge the new lubricant into the compressor to the same volume as removed in the previous step 7 Replace the filter drier by one compatible with SUVA HP80 or SUVA HP81 8 Pull vacuum on the entire system Follow normal proce dure to eliminate air and other non condensible gases from the circuit 3 to 5 mbar 9 Charge the installation with SUVA HP Refrigerant exclusively in liquid phase to 90 by weight of the previous R 502 charge To prevent liquid entering the compressor install a throttle valve in the charging line The optimum system charge will depend on the operating conditions of the installation and its internal configuration For most installa tions the appropriate charge will be between 90 and 95 of the R 502 weight 10 Re start the system and wait until the operating conditions stabilise 11 Optimise the performance of the system by completing the SUVA HP charge still in liquid phase into the compres sor suction port Make also use of the liquid line sight glass and of the pressure gauges when completing the refrigerant charge 12 When the system is operating normally with its final charge expect to find With SUVA HP80 discharge pres sure 2 to 3 bar higher than with R 502 but an equivalent dis charge temperature With SUVA HP81 discharge pres sure 1 5 to 2 bar higher If the evaporating temperature with Retrofitti
94. o flooding of low lying coastal areas Solar radiation is converted to heat energy by contact with the atmosphere and surface of the Earth A substantial part of that heat energy is radiated back towards Space but some is trapped in the atmosphere by various gases These are called Greenhouse Gases because they absorb and thus retain some of the outgoing heat energy an effect analogous to that of a greenhouse By raising the temperature of the earth s sur face these gases cause the effect called Global Warming The most significant greenhouse gas is carbon dioxide which is emitted and is present in the atmosphere in very large quantities Other gases including CFCs and many of their replacements are also greenhouse gases These are present in very much smaller quantities but have more effect per unit mass Comparison of the Global Warming Potential GWP of different gases is rather more complicated than comparison of ODPs In addition to the properties of the gas itself infrared energy absorption it is essential to take into account the aver age elapsed time before that gas is purged from the atmos phere There is a very wide range carbon dioxide remains in the atmosphere for over 500 years whereas HCFC 123 and HFC 152a have Estimated Atmospheric Lifetimes of less than 2 years Although carbon dioxide is the true basis for comparison it cannot be compared fully with other greenhouse gases because it does not have a finite at
95. o the work energy required by the com pressor The required work increases with pressure and tempera ture The required work is 57 kJ kg d Condensation Pressure bar Compressor exit 7 bar Condensation temperamre Qcd Compression Qcp Evaporation Enthalpy kJ kg 383 440 After the compressor the refrigerant vapour enters the con denser Fig 10 The first stage allows the vapour to cool down to the temperature corresponding to the saturation curve The second stage consists of condensing the refrigerant In other words the condenser will evacuate the heat taken up in the evaporator as well as the heat of compression Qev Qcp Qcd e COP The coefficient of performance is an important ratio in eval uating heat pumps it also applies to refrigeration It can be defined as follows COP heat obtained heat used Qcd Qcp In this case COP 440 237 440 383 3 6 2 3 Definition of types of fluorocarbons CFC chlorofluorocarbon Saturated aliphatic molecule con taining carbon C fluorine F and chlorine Cl atoms and no others Best known CFCs are CFC 11 CCI F and CFC 12 others include CFC 115 CF CC1F Used as refrigerants and in the past for other applications such as aerosol propellants solvents and plastic blowing agents because of their stability and other unique properties CFCs are now known to damage the ozone layer HCFC hydro chlorofluorocarbon Chemi
96. ods 28 Capacity of the vacuum pump 28 Quantity of liquid water 28 Disposal of contaminated refrigerant 28 Water and drying 29 Why worry about water 29 How much water is safe 29 Solubility 29 Solubility of water in liquid refrigerants 29 1 32 7 4 7 4 1 7 4 2 7 5 7 6 8 1 8 2 8 3 9 1 9 2 9 3 9 4 9 5 9 6 9 6 1 9 6 2 9 6 3 9 7 9 7 1 9 7 2 9 1 3 10 10 1 10 2 10 3 10 4 10 5 10 5 1 10 5 2 10 5 3 10 6 Solubility of refrigerant in water Moisture indicator Sight glass indicator Liquid indicator Field drying Function of the filter drier How to keep systems clean and dry Cleanliness and SUVA refrigerants Maintenance tips for cylinders Benefits of clean dry tubing and fittings Brazing and soldering Preparation of tubing Proper fit of joint Vent with inert gas Fluxes Applying heat Applying solder Melting solder Large diameter tubing Low melting silver bearing solder Breaking soldered or brazed joints Servicing all types of refrigeration systems Some local corrosion Epoxy resins compatibility Motor burn outs General Safety precautions Preliminary inspection What to do with the refrigerant Clean up No Significant quantities of carbon and other debris System is heavily contaminated Clean up filter drier Follow up page 29 29 29 29 30 30 3l 3l 31 31 33 33 33 33 33 34 34 34 34 34 34 34 35 35 36 36 36 36 36 37 37 37 37 37 1
97. one or more on loan from your SUVA Refrigerant supplier m Vacuum Pump of adequate capacity m Refrigerant Charging Manifold incorporating pressure gauges m Lubricant Charging Line m Leak Detector To check system for leaks after charging with SUVA 9 MP Since both blends contain HCFC 22 a conventional type preferably an electronic one may be used 1 3 5 Conversion procedure 1 Before starting the conversion to SUVA MP refrigerant record all the operating parameters of the system particularly the return gas temperature and subcooled temperature under normal operating conditions using the retrofit report which you can get from your SUVA Refrigerant supplier 2 Switch on the compressor lubricant heater if fitted if possible several hours before the conversion to ensure that the lubricant is completely de gassed 3 Using the Recovery Unit evacuate the R 12 from the system into the Recovery Cylinder s Record the weight of the recovered R 12 and return the recovered CFC refrigerant to your SUVA Refrigerant supplier 4 Ensure that the compressor cannot accidentally start up by removing the fuse or switching off the mains supply Attach a tag or label to the fuse holder or switch Make sure that the lubricant heater is switched off 5 If required drain the mineral lubricant from the compres sor from the lubricant separator and other components if fit ted as completely as possible Record the volume of
98. only molecular sieve granules for example m XH 9by UOP Division of Union Carbide m MS594 by GRACE Chemicals Some types of Solid Core filter drier which contain a mixture of different desiccants are compatible with SUVA9 MP refrigerants Consult your filter drier supplier Refrigerant Since SUVA MP39 and SUVA MP66 are near azeotropic mixtures it is essential to charge them exclusively in Liquid phase See Section 11 5 above For most installations the SUVA MP charge will be 75 to 9096 of the previous R 12 charge by weight Other components Generally it is not necessary to change the expansion device pressure gauges or other components of the system For moisture indicating sight glasses see chapter 7 above 19 3 4 Equipment required for conversion General considerations Use the recovery cylinders provided by your refrigerant sup plier Indicate clearly the refrigerant you want to recover when ordering the recovery cylinders to ensure that you use appro priate cylinders Do not over fill cylinders Do not mix refrigerants 45 DuPont SUVA Refrigerents Service Manual Equipment required m Personal safety equipment eye protection gloves m Recovery Unit To withdraw the R 12 as completely as possible from the installation and to minimise CFC emis sions to the atmosphere m Scale To weigh the R 12 withdrawn and to ensure the correct weight of the SUVA MP charge m Recovery Cylinder
99. onversion procedure 48 14 14 1 14 1 1 14 1 2 14 1 3 14 1 4 14 1 5 Safety Safe handling of SUVA HP refrigerants and environmental effects Introduction Properties Threshold limit value Handling precautions First aid Appendix SI conversion tables Physical properties and ashrae standard 34 classification of SUVA refrigerants Pressure enthalpy mollier diagrams for FREON 22 SUVA 123 SUVA 124 SUVA 125 SUVA MP39 SUVA MP52 SUVA MP66 SUVA HP80 SUVA MP81 SUVA 134a SUVA MP62 HFC 23 SUVA 95 SUVA 404A SUVA 407C SUVA 410A SUVA 507 SUVA 236fa page 50 50 50 50 50 50 51 51 52 54 73 Introduction 1 Introduction 1 1 The Ozone Layer 1 1 1 Historical background When CFC 12 was invented in 1928 it was welcomed as the perfect safe refrigerant chemically and thermally stable non flammable non explosive non corrosive and having very low toxicity Toxicologists do not describe any sub stance as non toxic In addition it was a good refrigerant None of that has changed So why are Refrigerant 12 and the other CFCs now prohibited from use The reason is that they are now known to damage deplete the Ozone Layer 1 1 2 What is the Ozone Layer The Ozone Layer is a band of relatively highly concentrated ozone up to 10 parts per million ppm in the strato sphere at a height of about 15 to 35 kilo
100. otal potential or possibility of that compound to deplete the Ozone Layer The ODPs of CFCs are high compared to other sub stances CFC 11 having the highest known ODP is rated as 1 0 There is no unit of measurement of ODP only com parative ratings The ODPs of various compounds together with their GWP ratings see 1 3 1 below are listed in Table 1 HCFCs for definition of these terms see 2 1 below have very much lower ODPs than do CFCs typically one tenth to one twentieth of the ODPs of CFCs HFCs have zero ODP Since they contain no chlorine or bromine they do not deplete the Ozone Layer 1 1 5 Current state of the science The current state of the science is that there is a virtually unanimous view among scientists who have studied the ques tion and are qualified to form an opinion that the Ozone Layer really is being depleted and that CFCs are a very sig nificant cause of the depletion There has not always been such nearly unanimous agreement DuPont SUVA Refrigerents Service Manual In 1972 a British scientist Professor James Lovelock published a report of his attempt to find CFC gases mainly CFC 12 and CFC 11 in the lower atmosphere tropo sphere He was surprised to find only very minor traces much less than he had expected Two American scientists Sherwin Rowland and Mario Molina basing themselves on Lovelock s report published in 1974 a paper that was chris tened The Ozone Theory They
101. ote that in several countries flared connec tions are no longer permitted in refrigeration piping m Good piping layout to avoid stress in the lines adequate supports particularly of long piping runs m Use of vibration eliminators m Use of good quality components designed for the appro priate pressure and temperature conditions m Installation of renewable components such as filter driers in such a way that they can be removed and replaced without unnecessary loss of refrigerant m A new system should be pressure tested before being evacuated and charged In addition while a certain number of isolating valves are desirable to avoid loss of refrigerant during servicing quality and mounting of valves should not permit them to become themselves the source of leaks The same consider ations apply to pressure relief devices Nevertheless experience has shown that it is virtually impossible to eliminate leaks completely particularly in systems that have been in service for some years It is therefore necessary to be able to detect leaks and identify them precisely so that they can be repaired 12 2 Symptoms Refrigerant leakage reduces the charge in the system Low refrigerant charge may be shown by 1 Bubbles in the sight glass These may also be caused by an obstruction in the liquid line for example a partial blockage of the filter drier 2 Evaporator temperature too low This also may be due to an obstruction in the
102. our products for your particular purposes This information may be subject to revision as new knowledge and experience becomes available Since we cannot anticipate all variations in actual end use conditions DuPont makes no warranties and assumes no liability in connection with any use of this information Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe any patent right L 10768 10 2001 DuPont Fluorochemicals
103. pressure control if possible The refrigerant flow can also be controlled by the cylinder valve to avoid ending up with a hose full of liquid refrigerant The same result can be obtained by closing the cylinder valve first when charging is finished 11 5 5 Watch the discharge pressure Watch the discharge pressure A rapid rise in pressure indi cates that the condenser is filling with liquid If this is the case the system pump down capacity has been exceeded Stop charging from the cylinder and open the liquid line valve If the system still seems low on charge an auxiliary receiver may be needed When the proper weight of refrigerant has been added close the cylinder valve and let the low pressure control stop the compressor Close the charging port valve and vent refrigerant vapour from the hose by loosening connection Open the liquid line valve or receiver outlet valve and check the operation of the system Replace cap on cylinder valve and charging valve Plug both ends of the charging hose or manifold so it will be clean for the next use 39 DuPont SUVA Refrigerents Service Manual 11 6 System without a sight glass The following suggestions may be useful if a sight glass is not installed and information on the correct charge is not available 1 Connect charging line and gauge manifold to compressor 2 Attach thermometer to evaporator outlet 3 Run compressor and after about ten minutes read both gauges and
104. ractice to maintain cleanliness Buy quality SUVA Refrigerants in cylinders filled by Du Pont authorised reloaders to be sure that you are getting a clean dry refrigerant Do not try to transfer SUVA or other refrigerants in the field because m Itis impossible to keep out all moisture and air m Thereceiving container is seldom physically clean m The receiving container is seldom uncontaminated chemically m The danger of accidentally over filling a service cylinder always exists The lack of proper transfer equipment makes field transferring uneconomical and hazardous In an emergency if transferring refrigerant from one container to another is unavoidable be sure to charge any transferred refrigerant through a fully activated drier about the same size as would be used on a 1 kW system 8 2 Maintenance tips for cylinders Always replace outlet connection caps as soon as the valve is closed and the cylinder disconnected This prevents dirt from entering the valve and reduces the chance of damage to threads m Store SUVA refrigerant cylinders in a cool dry place if possible upright secured for example by a chain to prevent falling m Donot force cylinder connections You can strip threads which in turn can cause leaks Remember valves cannot be repaired when attached to the cylinder m Donottamper with built in safety devices on the cylinder valve m Do not use cylinders as rollers or supports 8 3 Benefits o
105. re Enthalpy charts for non azeotropic refriger ant blends are also slightly different from those for single component refrigerants The isotherms or lines of constant temperature in the two phase region are not parallel to the isobars or lines of constant pressure Fig 12 the Evaporator and Condenser glides can be seen The Pressure Enthalpy chart for a non azeotrope is used as explained in the Fig 12 to define and describe the operation of the refrigeration system 2 6 The practical implications of using Non Azeotropic Refrigerants There are certain important differences between non azeotropes and single component refrigerants that must be borne in mind when using SUVA Blends These will be described in more detail in the appropriate sections of this manual 1 Always charge liquid phase Because the equilibrium vapour composition is different from the composition of the liquid the refrigerant must be transferred from its container using the liquid line If the cylinder does not have a dip tube it must be turned upside down It is not a problem if the liquid flashes into vapour after it has entered the transfer line This liquid phase charging is not necessary if the entire contents of the cylinder is to be transferred to one refrigeration unit 2 When adjusting the operation of the refrigeration system it is important to use the correct Saturation Curve For Evaporator Superheat compressor suction the Satu rated Vapour
106. refrigerant into system 15 Replace cylinder valve cap and fit flare plugs in open ends of charging and gauge lines Replace plugs in gauge ports of compressor service valves Notes 1 If possible refrigerant should always be charged by weight using a good scale or by volume using a charging cylinder with a scale that compensates for changes in refrig erant density due to temperature There must be appropriate scales for different refrigerants 2 Sight glass charging It used to be customary to charge CFC refrigerants until no bubbles appeared in the sight glass This method is not always applicable to SUVA refrigerants particularly when using POE lubricants For correct charg ing see paragraph 11 6 3 If cylinder pressure drops too low for further charging before the job is finished place cylinder in a bucket of warm 25 45 C water or use a heat lamp to increase pressure Do not apply heat with a torch Never heat cylinder above 50 C 11 5 Liquid charging Charging the refrigerant in the liquid phase has always been customary for larger systems It is essential for charging SUVA blends If a complete charge is to be added to an evacuated system the liquid is frequently charged through the compressor discharge service valve The compressor is not operated while charging The procedure for attaching the manifold and purging the lines is similar to that described for vapour charging On most systems a chargi
107. rigerant Charging Lines in the form of a manifold incorporating pressure gauges m Lubricant Charging Line m Leak Detector to check system for leaks after charging with SUVA HP Since both blends contain HCFC 22 the conventional type preferably electronic may be used 1345 Conversion procedure 1 Before starting the conversion to SUVA HP refrigerant record all the operating parameters of the existing R 502 system particularly the return gas temperature and the sub cooled temperature under normal working conditions Use the retrofit report available from your SUVA Refrigerant supplier 2 Switch on the compressor lubricant heater if possible several hours before starting to evacuate the system to ensure 48 that the lubricant is fully de gassed 3 Using the Recovery Unit evacuate the R 502 from the system into the Recovery Cylinder s provided Record the weight of the R 502 and return the recovered refrigerant to your SUVA Refrigerant supplier 4 Ensure that the compressor cannot accidentally start up by removing the fuse or locking open the power switch Affix a tag or label to the fuse holder or switch Make sure that the lubricant heater is switched off 5 Where applicable drain the mineral lubricant from the compressor and from the lubricant separator and other components if fitted as completely as reasonably possible Record the volume of lubricant removed then place it in an appropriate recipient t
108. rmitted to be manufactured or sold in Europe and in most other regions of the World Therefore if an existing system loses its charge of CFC refrigerant as a result of a leak an accident or because it was necessary to open up the system for maintenance that system must be charged with a non CFC refrigerant when it goes back into service The choice that the owner of the system must face is m To attempt to find some reclaimed CFC refrigerant to min imise the change This course of action will become increasingly difficult and expensive m To scrap the equipment and replace it by a new unit running on a HFC or other permanent replacement non CFC refrig erant Unless the equipment is in poor condition or approaching the end of its useful life this is an expensive choice m To replace the CFC refrigerant with a HFC refrigerant such as SUVA 134a This is complicated time consuming and expensive for normal commercial and industrial systems but is generally recommended in the case of Automobile air conditioning systems m Toreplace the old charge with a SUVA service refriger ant It is this comparatively easy and inexpensive course of action that is normally recommended It requires min imal change to the refrigeration system 13 2 How to choose the non CFC refrigerant The first step is to find out which refrigerant was previously used In the absence of correct labelling of the system indi cating the refrigerant type the charge
109. rs sealed until the moment of use As far as possible purchase lubricant in the correct sized containers for each job Never pour lubricant in the open from one container to another Charge lubricant into a compressor using the methods outlined below or equivalent methods recommended by the compressor manufacturer When removing used lubricant from a compressor wear eye protection and rubber neoprene or similar gloves Degraded lubricant may contain acidic products 5 6 3 Charging the lubricant This is necessary in these cases Although most new compressors are supplied already charged with lubricant there may be exceptions where an initial charge is the responsibility of the installation or service engineer A top up charge is normally required to compensate for the part of the initial charge that is in circulation Check the compressor manufacturer s instructions for the correct level in the lubricant sight glass this may vary from one model to another Read the level when the system has settled down under normal operating conditions Overfilling with lubricant can damage the compressor When changing refrigerant it is usually necessary to change the lubricant The volume of the new lubricant to be charged is normally the same as the volume removed It will be less than the complete initial charge unless it has been decided to remove the lubricant in circulation as well Lubricant may have degraded in service and need to
110. s necessary to cut the tubing use a tube cutter rather than a hack saw If you use a saw slant the tubing downward if possible to keep the metal dust and small pieces out of the section to be used Of course 1f both sections are to be used this is difficult Remove burrs from cut edge with a special tool or a file or knife if you cannot obtain the tool Both the outside of the tubing and the inside of the fitting must be bright shiny and clean Use a soft wire brush or sand cloth Emery cloth is not recommended since it may leave marks in the copper The surface should be smooth so the sol der will flow evenly The cleaning should be done just before soldering to avoid reoxidation of the surface On the other hand do not file away more copper than is necessary to make the surface clean and bright 9 2 Proper fit of joint The clearance between the tube and the fitting should be 0 04 mm This fit will permit the tube to enter the fitting easily without binding and will not be too loose Clearances that are too tight will restrict the capillary flow of solder in the joint and a poor or incomplete bond will result Clearances that are too large will not permit the cap illary flow of solder and voids will cause poor joints A joint with 0 04 mm clearance will give maximum joint strength because the solder will be in shear stress If the clear ance is too large the solder will be in tensile stress Resistance to tensile stress is lower than
111. s on actual refrigeration systems with mixtures of alkylbenzene AB and MO e g Shell 2212 have given satisfactory results So have polyolester POE lubricants particularly with SUVA HP80 Other laboratory tests have shown that SUVA HP81 is adequately miscible with mineral oils Nevertheless it is rec ommended to use the same lubricants as proposed above for SUVA HP80 50 50 mixtures of AB and MO or POE In many R 502 refrigeration systems AB and AB MO lubricant mixtures are already used Basically the same viscosity should be used as with R 502 However you might consider the use of the next higher viscos ity grade if charging POE lubricants In all cases you should consult your lubricant supplier and compressor manufacturer Materials of construction Itis not necessary to replace elastomers plastics metals wire insulation or other components from the existing R 502 system provided that they are in good condition For choice of desiccants in the filter drier see 13 4 3 below 13 4 3 Components to change Filter drier The filter drier or its core must be changed and replaced by a unit containing molecular sieve desiccant compatible with SUVA HP refrigerants Filter driers are available that con tain only molecular sieve granules for example m XH 9by UOP Division of Union Carbide m MS594 by GRACE Chemicals Some types of Solid Core filter drier for example sporlan Catch ALL which contains a m
112. service valve connection at gauge port 8 Purge vapour from cylinder up to compressor suction ser vice valve 9 Tighten suction service valve connection at gauge port Open both compressor service valves 10 Place cylinder of SUVA refrigerant on weighing scale 11 Pressurise system to full cylinder pressure and make final leak check 12 Start compressor Run until head pressure and suction pressur stabilise If system has a low pressure control this may cause the compressor to short cycle If this occurs note the cut out pressure and admit refrigerant from the cylinder to increase suction pressure by 0 7 to 1 0 bar above the cut out setting Open the cylinder valve completely and control the flow of refrigerant from the manifold From time to time note suction pressure with the cylin der valve closed From time to time note discharge pressure to see that it does not rise rise above the level normally expected under operating conditions For air cooled systems the discharge pressure should be approximately the the pressure corre sponding to ambient temperature plus 11 C refrigeration to 17 C air conditioning 13 When correct weight of refrigerant has been introduced close cylinder valve and disconnect charging line 14 When satisfied that the system is operating as it should back seat both suction and discharge service valves Bleed pressure from both gauge lines through the manifold charg ing port Charging
113. shortton USA kg 907 18487 1long ton UK kg 1016 0471 1 grain kg 6 480 105 Specific volume 1 cm3 g m3 kg 103 11 0 m3 kg 1 1 cu ft Ib m3 kg 62 42795 10 3 1 cu in Ib m3 kg 0 361271 10 4 1 Imp gal lb m3 kg 0 01002 1 US gal Ib m3 kg 0 008345 Density 1 kg l kg m3 103 1 g cm3 kg m3 103 1 g l kg m3 1 1 Ib cu ft kg m3 16 01847 1 Ib cu in kg m8 27680 1 Ib Imp gal kg m3 99 77644 1 Ib US gal kg m3 119 8264 Force 1 dyne N 10 5 1kg N 9 8066 1 sthene sn N 103 1 poundal N 1 383 10 1 Energy work 1 erg J 107 1 kgm J 9 8066 1kJ J 103 1 kcal J 4 184 103 1chh J 2 648 106 1 kWh J 3 600 106 1Hph J 2 684 106 1 BTU mean J 1055 87 Power 1 erg s 10 7 1kgm s 9 8066 1 kW 103 1 kcal h 1 163 1ch 0 735 103 1 kcal s 4 184 103 1Hp 745 7 1BTU h 0 293 1 T Ref 3516 8 53 sjue1oD14jo14 YANS JO uoneoyisse piepue s pue sonaoedoad e53 is udq II 90 d9 Jeq LO L e u SOL LEL 0L 8CL 601661 sOL SCL OL 62 L 11 01 LL 10 0 LO O 16100 OLLOO 8110 0 42100 Sedu 2 GZ AiisoosiA inode p3 0 e u OL GCL v0L 88 1 01861 01871 vcOL SEL 0610 1 0 610 0Z 0 ZEL O vLEO 9570 Z9L0 86L0 2 9 Asos pinbr Jeq LO L O GZ inoden elu zOLtvCLzOL 66LL z OL 9VE L z 0L GOZ L z 0L 99 L 6LLOO 180100 60100 9100 99100 08100 2100 000 90100 UA AuA nonpuoo euueu L 2 92 p nb
114. ssolves in the oil and the oil refrigerant mixture has a lower viscosity than the oil by itself The amount of refrigerant dis solved in the oil at a given point in the circuit is a function of m Thetype of refrigerant m The lubricant m Temperature more refrigerant will be dissolved in the oil at a lower temperature As the temperature of the lubri cant rises refrigerant will boil off out of the solution m Pressure an increased pressure will counteract the effect of rising temperature by forcing the refrigerant to remain in the solution The viscosity of the refrigerant lubricant mixture affects how easily the lubricant phase can be returned to the com pressor Even if a refrigerant and lubricant are immiscible the refrigerant may be partially soluble in the lubricant Refriger ant solubility in the lubricant helps to reduce the viscosity of the lubricant making it easier for the lubricant phase to flow through the system In a refrigeration system a lubricant which is immiscible with the refrigerant will form a separate phase and can col lect generally referred to as oil logging in the evaporator or at low points in the system Lubricants and their relationship with SUVA Refrigerants 5 5 3 Lubricant Circulation Oil return to the compressor In a well operating system all the lubricant that leaves the compressor moves around the circuit with the refrigerant and returns to the compressor where it again acts
115. t SUVA Refrigerents Service Manual PRESSURE MPa PRESSION MPs DRUCK MPa B uy u ru zi g aska a s a 895388 8 8 2 muna e a 8 Sg _ 8 Bc 2 D lt amp T 2 B 3 m 2 a 5 E 5 mn Pressure enthalpy of SUVA HCFC 123 SPECIFIC ENTHALPY kJ kg 250 250 SPECIFIC EMTHALP kde 200 SE RB s s TG SSS B d s UEC NOISSSHd 9 3Hnssdgd 58 Appendix SPEZIFISCHE ENTHALPIE ENTHALPIE SP CIFIQUE SPECIFIC ENTHALPY k likg PRESSURE MPa PRESSION MPa DRUCK MPa ARO KANT PERT GAIA ERTIBCHER FG F F A amu i lt i s 2 Es im Fh a k A 1 M J Shp gt Lu H i i E m d x o m Pressure enthalpy of SUVA 124 200 150 100 8 2882885 R Hegi waned garung a eq NOISSdHd zl Hem E E uu Tu T Te TU x L i re n e Et bue 1 D Pr ll a aa To NI diy _ HEH SHNSSddd i b 1 J i j r F zi Goo i SPEZIFISCHE EMTHALPIE klk ENTHALPIE SPECIFIQUE k J kal _ a EH i Anu 14 ga SPECIFIC ENTHALPY keg T TE f
116. ted vapour Allows for varia tions in evaporator load and protects the compressor Accumulator Heat exchanger absorbs heat from the ambient medium cools the service medium and allows evaporation of the refrigerant Evaporator A gas pump causing the refrigerant vapour to change from low pressure to high pressure Compressor Heat exchanger rejects heat from the system Condensation of the refrigerant occurs in the condenser Condenser Allows the refrigerant to go from high to low pressure and regulates the flow into the evaporator Expansion Device Diagrams Water a Temperature Enthalpy Fig 4 Temperature YC Saturated liquid Saturated vapor Enthalpy OkJ 418 kJ 2671 kJ Background information At atmospheric pressure of 1 bar one kilogramme of water changes as on Fig 4 A B The liquid is heated from 0 C to 100 C At B the first vapour appears An energy heat input of 418 kJ is required B C The fluid is changed from liquid to saturated vapour At C the last liquid has disappeared During this change of state temperature is constant and an energy input of 2671 418 kJ 2253 KJ is required to ensure this transformation C D The vapour can be further heated To increase the tem perature of 1 kilogramme vapour by 1 C an input of 1 88 kJ 0 45 kcal is required b Pressure Enthalpy A diagram as below exists for each type of SUVA refriger ant Fig
117. ter Always consult a doctor or an optician Persons overcome by SUVA vapour They should imme diately go or be moved to fresh air Lie down do not take exercise Use artificial respiration if person is unconscious Call a doctor Do not use chemical products of the adrenaline ephedrine group In combination with excessive SUVA vapour concentration these can produce cardiac arrhythmia leading to ventricular fibrillation 51 DuPont SUVA Refrigerents Service Manual Appendix l SI Conversion tables Definitions The definition of the most important SI units of the metric system are as follow Length Meter m 1misthe length ofthe path travelled by light in a vacuum during a time interval of 1 299 792 458 of a second Mass Kilogramme kg 1 kg is the mass ofthe international pro totype in custody of the Bureau Interna tional des Poids et Mesures at S vres near Paris Time Second s 1sisthe duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state 2s of the Caesium 133 atom Force Newton N 1 Newton is the force which applied to a body having a mass of 1 kilogramme gives it an acceleration of 1 m s2 Temperature Kelvin k Kelvin is the interval of the thermody namic scale on which the temperature of the triple point of water is 273 15 degrees Energy Joule J 1 Joule is the work done when a force of 1
118. the thermometer 4 Add refrigerant 5 Close cylinder valve and after a few minutes read the suction and discharge pressure and the thermometer Both gauges should read a little higher than in 11 7 3 The ther mometer may read a bit lower On water cooled systems having a good supply of cold water discharge pressure may not increase 6 Repeat steps 4 and 5 until no further change is noted in the gauge reading 7 Read the thermometer and check against the refrigerant saturation temperature as shown by the suction pressure gauge that is the corresponding refrigerant temperature at low side pressure Difference between saturation tempera tures at evaporator pressure and the thermometer reading should be the superheat setting of the expansion valve This value is usually 5 6 C Allow for a thermometer reading of 1 C higher than the actual vapour temperature 8 Again add a small amount of refrigerant and observe the thermometer for any change No change indicates that full liquid flow is being supplied to the expansion valve System operating conditions must have reached an equilibrium before this final reading is made 9 Adda reserve of refrigerant based on size of the system The above procedure can be applied to capillary tube systems with the exception of step 9 40 11 7 Charging a small capillary tube system or a VRV Variable Refrigerant Volume air conditioning unit The best way to charge a small capi
119. tor The oil must atthe same time be viscous enough to lubricate and to perform its sealing function at relatively high temperatures in the com pressor Stability is essential because the oil remains constantly in the system where itis in continual contact with system com ponents in different materials and with the refrigerant itself Some oil is likely to leak into the circuit even with an externally lubricated or oil free compressor The essential properties of a refrigeration oil are m Adequate lubrication Stability m Solubility in refrigerant Other properties include low floc point and for hermetic or semi hermetic compressors dielectric strength As explained above natural mineral oils are not used with modern non CFC refrigerants with the exception of HCFC 22 All HFC refrigerants including SUVA blends operate with various types of tailor made Synthetic oils 5 5 Lubricant viscosity Itis necessary to distinguish between the standard viscosity of an oil used to identify it and the actual viscosity of that same oil in a refrigeration system 5 1 Standard viscosity Standard viscosity is measured at 40 and expressed in centiStokes cSt Lubricants in use range from 15 to more than 170cSt Those most frequently used are either 32 or 68 cSt vis cosity Lower viscosities are used in the smaller hermetic com pressors Higher viscosities such as 100 cSt are found in large compressors particularly screw
120. uantity depending on the design of the system particularly the length of the piping runs The effect of too much residual MO will be oil return problems and possibly heat transfer problems also If the system is equipped with sufficient instrumentation to detect loss of cooling performance it can be checked if it is performing poorly an additional oil change should be carried out If the consequences of system under performance would be serious for example in process temperature control or in holding chilled or frozen food within close limits an extra oil change should be considered as an insurance The major oil companies that specialise in producing and supplying refrigeration oils offer analytical services to inform the refrigeration engineer of the proportion of MO to AB or POE lubricant and also separately of the condition of the MO which may have deteriorated during use Oil test kits that can be used in the field to measure the residual mineral oil content in POE lubricant are readily available 21 DuPont SUVA Refrigerents Service Manual 5 4 Lubricant quality Refrigeration oils have special requirements beyond those of other industrial lubricants With a few exceptions the oil is in constant contact with the refrigerant and to a greater or lesser extent circulates with it The oil must be able to circulate freely throughout the system it must remain fluid at low tempera tures so as not to accumulate in the evapora
121. und based findings of the Survey and proved the link with chlorine chemistry The Ozone Theory has now 1995 been shown to be essentially correct 1 1 6 Other theories Other theories about the Ozone Layer need to be mentioned They frequently seem convincing and attract attention because the Layer is not constant As mentioned in 1 1 2 above there are important variations between Summer and Winter Thickness of the Layer also varies according to time of day and on a longer cycle of about eleven years The Ozone Layer is not equally thick over the whole Word it is thickest over the North and South Poles and thinnest over the Equator It is consequently very difficult to measure the Layer accurately and thus to detect the small changes which fortu nately are all that have occurred to date Major volcanic eruptions such as Mt Pinatubo in 1991 do temporarily increase ozone depletion The effect of such events is relatively short term however and while often signif icant for one to three years after the eruption sinks into the background quite rapidly There are not enough volcanic erup tions to explain the observed decrease in stratospheric ozone Supersonic aircraft flying in the stratosphere probably do have an effect on the Ozone Layer but not a significant effect at the present number of flights Methyl bromide is considered to be a significant ozone depleting compound There is a natural source of methyl bromide in the
122. y for use in existing R 502 refrigeration installations to enable them to remain in service 13 4 1 Selection of the refrigerant The choice between SUVA 80 SUVA 81 will be based on the application and its typical operating conditions SUVA 80 For low temperature applications with an evaporating temperature of the order of 40 C SUVA HP80 offers a similar discharge temperature to R 502 and improved refrigerating capacity However the COP is slightly lower than that of R 502 SUVA HP81 For installations where energy efficiency is the main consideration SUVA HP81 offers the best COP typically equal to or better than that of R 502 and an increase in refrigerating capacity In view of its performance SUVA HP81 is the ideal candidate for commercial applications having evaporating temperatures no lower than 30 C Important note If SUVA HP81 is used in a system with an evaporating temperature of the order of 40 C the com pressor discharge temperature may be as much as 15 C higher than with R 502 Such excessive discharge tempera tures may adversely affect the lubrication system and shorten the life of the compressor 13 4 2 Compatibility Lubricants Tests have shown that SUVA 80 is slightly less miscible with mineral lubricants MO than R502 Extensive field experience has shown that in practice in many situations SUVA 80 does perform reliably when using mineral oils Test

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