IOM - Colmac Coil Manufacturing, Inc.
Contents
1. 20 ENG00018005 Rev 10 6 15 n Figure 6 WATER DEFROST PIPING SPR TOWER COIL OPTION A MASTER BALANCING VALVE N 3 SON GATE VALVE T ee wl Pd FLEXIBLE COUPLER SUPPLY DRAIN LINES PITCHED 1 2 PER SOLENOID VALVE2. VA i 1 sessist ji A pua 7 REMOVE LIFTING ANGLE AFTER PLACEMENT E NOTE NEVER LIFT COIL WITH DRAINPAN USE SUPPLIED LIFTING ANGLES 18 00018005 Rev 10 6 15 Figure 3 STACKING MULTIPLE COILS
3. DO NOT PLACE STRAPS IN DIRECT CONTACT WITH POSITION STRAPS WITHIN 22 000 NYLONSTRAP THREE INCHES OF TUBESHEETS M ENG00018005 Rev B 10 6 15 NEVER EXCEED 45 TO AVOID DAMAGE TO COIL TOP PAN 19 m Figure 5 CRANE RIGGING INSTRUCTIONS COILS WITH LIFTING DEVICES DO NOT LIFT UNIT WITHOUT SPREADER BAR Iu HHH HEEE MI
4. mlalululnininlulninialalaininininininlalnialalainiy gor d io Bh uv Bh Ed ms zw mh 5 fi 7 Pa BOLT COILS TOGETHER d TT gt AT EACH LEG AFTER COIL MAY NEED SECURED PLACEMENT FORKLIFT TO AVOID TIPPING 2 0
5. JE x x JE JE I ka JE JE JC JE JE JE 1 JC JE js 4 CRANE RIGGING INSTRUCTIONS COILS WITHOUT LIFTING DEVICES DO NOT LIFT UNIT WITHOUT SPREADER BAR
6. s UNITS INDIVIDUALLY TRAPPED gt TO PREVENT DRAWBACK OF WARM AIR TO DRAIN 21 ENG00018005 Rev 10 6 15 Figure 7 WATER DEFROST PIPING SPR TOWER COIL OPTION B MASTER BALANCING VALVE GATE VALVE P FLEXIBLE COUPLER SUPPLY DRAIN LINES PITCHED 1 2 PER FOOT SOLENOID VALVE SNSSSSSSSNSSSSSSNSSSNSNSNSSNSNSNSNSNSNSNSNSNSNSNSNSNSSNSNSNSNSNSNSNSS XJ AD NONO NO NO NO ON A NO NONO ND NO NO NT SS nmm row 4 En TO DRAIN TO DRAIN 22 ENG00018005 Rev 10 6 15 mn Figure 8 DIELECTRIC FLANGE UNION
7. STEEL HEX NUT 3 4 10 Mu SAE FLAT WASHER in accordance with ASME B31 5 5 STEEL FLANGE lt GASKET Ni E MN FLANGE SYSTEM 07777 7 727 2277 2 DIELECTRIC HOLE LINER SS SASS AG S COIL 27 AN SAE FLAT WASHER N 9 DIELECTRIC FLANGE UNION 7 WELDED PLUG BIMETALLIC COUPLING SYSTEM DO NOT WELD PIPING IN THIS AREA BLOCK 4 0000 23 ENG00018005 Rev 10 6 15 Figure 10 HOT GAS DEFROST PIPING RECIRCULATED BOTTOM FEED EVAPORATOR HAND E XPANSION VAL GLOBE VALVE GAS POWERED SUCTION STOP VALVE SOLE NOID VALVE DEFROST PRESSURE REGULATOR CHECK VALVE STRAINER BLOW OFF D UNIT COOLER DRAIN HGD HOT GAS DEFROST SUP PLY COOLING LTRS LOW TEMP RECIRCULATED SUCTION COIL LOW TEMP RECIRCULATED LIQUID A PILOT SOLENOID VALVE 88 58 B GAS POWERED SUCTION STOP VALVE 2 OR HC K2 EQUALIZING BLE ED VALVE 58 OR 58 D DEFROST RELIEF REGULATOR 4 OR 4 E LIQUID SOLENOID S4A OR HS 4A F HOT GAS SOLE NOID S 4A OR HS4A G SOFT START HOT GAS SOLE NOID S8 OR HS 8 HOT GAS LOOP RE COMM ENDED FOR EVAPORATORS OF 15 TONS OR GREATER COOLING CAPACITY gt SATURATED LIQUID FLOW SATURATED LIQUID 8 VAPOR FLOW 24 ENG00018
8. 00019560 If an overload or a fault current interruption occurs circuits must be checked to determine the cause of the interruption If a fault condition exists the current carrying components should be examined and replaced if damaged and the integral current sensors must be replaced to reduce the risk of fire or electric shock 00019561 ENG00018005 Rev 10 6 15 DANGER Rotating Machinery Equiptment may start and stop without warning Do not operate with guards removed Lockout prior to servicing 00019536 DANGER Pressurized Gas Liquid Contains pressurized gas liquid Evacuate system in accordance with applicable regulations and safety standards prior to servicing Only qualified personnel should 00019634 Safety Relief Valve Required This component is intended to be installed in a system protected with an appropriate safety relief valve Failure to do so may result in personal injury or death 00019628 Hot Surfaces Contact may cause burn Do not touch 00019628 ENG00018005 Rev 10 6 15 2 INSTALLATION 2 1 Inspection 2 1 1 Damage or Shortage Upon receipt of equipment inspect for shortages and damage Any shortage or damage found during initial inspection should be noted on delivery receipt This action notifies the carrier that you intend to file a claim Any damaged equipment is the responsibility of the carrier and shou
9. e Install a pressure regulator in the compressor room at the hot gas takeoff Set the regulator to approximately 100 psig 689 5 kPa then size the piping to achieve 75 to 85 psig 517 to 586 kPa condensing pressure at the evaporators accordingly e In branches leading to each evaporator from the main hot gas line install a pressure regulator set at approximately 75 to 85 psig 517 to 586 kPa then size the branches accordingly 3 2 9 Halocarbon Hot gas piping is typically sized to accommodate twice the normal refrigerant mass flow from the evaporator Pressure drop is not as critical for the Halocarbon defrost cycle so refrigerant velocity can be used as the criterion for line size It is suggested that hot gas lines are sized for the refrigerant velocity between 1000 to 2000 ft min 5 to 10 2 m s ENG00018005 Rev 10 6 15 3 3 Water Defrost Piping Supply Water 3 3 1 Water defrost and wash down consists of distributing water over the coil surface for a pre determined period of time Upon defrost wash down termination sufficient time must be given to allow the water to drain from the piping before the freezer is reactivated 3 3 2 Figures 6 and 7 show the water defrost and drain piping layout for the two different tower installation configurations A solenoid valve in the water supply line to one or more defrost units opens under control of an automatic timer to allow water to the units Approximate water v
10. 02225 COIL Manufacturing Inc Installation Operation and Maintenance 0018005 Rev B SPR SPIRAL TOWER COIL Contents INSTALLANMON eT s Nice 8264 1672 e 5 GENERAL OPERATION m HOT GAS DEFROST in i ida WATER DEFROST OPERATION 2555 t ita i 11 WATER AND HOT GAS DEFROST OPERATION 13 ELECTRIC DEFROST nena aaa ee ena eo a ana an kia aasa 13 AIR DEFROST 14 11 s i i re S 15 12 TROUBLESHOOTING QU EX uU VIR CY E CE SU SE Xu 16 COON OA B 0 N Air Defrost Electric Defrost Hot Gas Defrost Water Defrost Water and Hot Gas Defrost Low Temperature less than 20 F 6 7 C Medium Temperature
11. Defective defrosting timer thermostat pressure regulator Hoom thermostat set incorrectly Low refrigerant charge Airflow restricted to evaporator Undersized evaporators for required heat load Fan motors not operating Insufficient refrigerant flow Unit cycling too frequently causing excessive fatigue related wear and tear Check quality of power supply Unit too close to wall product etc for proper return air supply to fan Unit obstructed with ice blockage No airthrow straightener specified with unit purchase Fan and or fan motors not operating correctly VFD fan speed too low ENG00018005 Rev 10 6 15 SYMPTOM POSSIBLE CAUSE POSSIBLE SOLUTION 4 Decrease duration of each defrost cycle Decrease number of defrost cycles Repair or replace as necessary Check thermostat and adjust appropriately Add refrigerant Check evaporator for airflow blockage including ice buildup foreign matter etc Clean as necessary If heat load exceeds design conditions evaporator operating conditions may have to be changed or evaporators will need to be added to the conditioned space Check fans and fan motors for proper operation Replace or repair as needed Check strainers hand expansion valves etc Limit number of cycles whether it is for capacity control or defrost operation Install power conditioning equipment phase failure relays etc Relocate unit to allow f
12. restart the fans ENG00018005 Rev 10 6 15 6 4 3 Gravity Flooded Evaporators See Figure 13 Close Liquid Solenoid and stop fan motors Open Hot Gas Pilot Solenoid to close the two Gas Powered Stop Valves in the coil liquid and suction lines On Coils of 15 tons cooling capacity and larger open Soft Start Hot Gas Solenoid to gradually bring coil up to near defrost pressure Open Hot Gas Solenoid to start defrost Duration of defrost should be long enough to clear coil and pan Extending the defrost period longer than this is not necessarily better Close Hot Gas Solenoid and Soft Start Hot Gas Solenoid if applicable to end defrost Energize the Defrost Relief Regulator to the wide open position to gradually bring the evaporator back down to suction pressure equalize Close Hot Gas Pilot Solenoid to open the Gas Powered Suction Stop Valves At the same time de energize the Defrost Regulator Valve Open the Liquid Solenoid After a delay to refreeze remaining water droplets on the coil restart the fans 6 4 4 Setting Hot Gas Defrost Timer Time periods should be set as follows Length of defrost should be set to the minimum time necessary to melt all frost Defrost operation beyond this point will convert liquid water to steam leading to secondary condensation and freezing on non heated areas of the tower coil and introduced unwanted heat gain into the controlled space Depending on frost load
13. unknown it may be measured by installing a gauge and valve at the takeoff point The pressure should be measured with water flowing near the desired rate ENG00018005 Rev 10 6 15 A In some instances as with 2 pipe it may be desirable to use a solenoid valve to fit the next size smaller pipe As with all valves and fittings determine the correct equivalent length to calculate pressure loss 3 4 Defrost Drain Piping 3 4 1 Typical drain connections will be piped to the pitched floor of the freezer see Figure 7 This will consolidate all of the drain lines into one large freezer drain you are going to pipe the drains to the floor please skip to the next section Connection Sizes 3 4 2 Observe the following guidelines if you are going to pipe the coil drain connections through the refrigerated space see Figure 6 Drain connections from the drainpan should be individually trapped Individual trapping prevents warm air from being drawn back through the drain pipes of non defrosting units Drain line size should be at least equivalent to the unit drain connection size For Water Defrost use Table 5 for sizing defrost drain line sizes e Note Water defrost is not recommended for sequential defrost systems e Within the refrigerated space the drain line should be pitched sharply down at least 1 2 in ft 4 cm m and be as short as possible It should also be insulated along its entire length Tr
14. 005 Rev 10 6 15 Figure 11 HOT GAS DEFROST PIPING RECIRCULATED TOP FEED EVAPORATOR UNIT COOLER COOLING COIL HOT GAS LOOP ENG00018005 Rev 10 6 15 4 ADA x A HGD LTRS LTRL 1 HAND EXPANSION VALVE GLOBE VALVE GAS POWERED SUCTION STOP VALVE SOLENOID VALVE DEFROST PRESSURE REGULATOR CHECK VALVE STRAINER BLOW OFF DRAIN HOT GAS DEFROST SUPPLY LOW TEMP RECIRCULATED SUCTION LOW TEMP RECIRCULATED LIQUID LIQUID SOLENOID S4A OR HS4A PILOT SOLENOID VALVE 58 OR HS8 GAS POWERED SUCTION STOP VALVE 2 2 DEFROST RELIEF REGULATOR W WIDE OPENING FEATURE FOR EQUALIZING A4AB OR HA4AB HOT GAS SOLENOID S4A OR HS4A SOFT START HOT GAS SOLENOID S8 OR HS8 RECOMMENDED FOR EVAPORATORS OF 15 TONS OR GREATER COOLING CAPACITY HOT GAS FLOW SATURATED LIQUID FLOW SATURATED LIQUID amp VAPOR FLOW DEFROST PRESSURE REGULATOR OPERATES WIDE OPEN DURING NORMAL OPERATION AND OPERATED AS REGULATOR DURING DEFROST 25 Figure 12 HOT GAS DEFROST PIPING DIRECT EXPANSION EVAPORATOR UNIT COOLER COOLING COIL HOT GAS LOOP ENG00018005 Rev 10 6 15 7 XoXo XH Xi LTS 1 HAND EXPANSION VALVE GLOBE VALVE GAS POWERED SUCTION STOP VALVE SOLENOID VALVE DEFROST PRESSURE REGULATOR THERMAL EXPANSION VALVE CHECK VALVE STRAINER BLOW OF
15. 20 F 6 7 up High Temperature 40 F 7 2 C and up 1 SAFETY INSTRUCTIONS To avoid serious personal injury accidental death or major property damage read and follow all safety instructions in the manual and on the equipment Maintain all safety labels in good condition If necessary replace labels using the provided part numbers This is the safety alert symbol is used to alert you to potential personal injury hazards Obey all safety messages that follow this symbol to avoid possible injury or death DANGER indicates a hazardous situation which if not avoided will result DANGER in death or serious injury WARNING indicates a hazardous situation which if not avoided could result in death or serious injury NCAUTION CAUTION indicates a hazardous situation which if not avoided could result in minor or moderate injury NOTICE NOTICE indicates instructions that pertain to safe equipment operation Failure to follow these instructions could result in equipment damage DANGER Hazardous Voltage Unit may have more than one electrical power supply De energize and lockout prior to servicing 00019535 To maintain over current short circuit and ground fault protection the manufacturer s instructions for selection of over load and short circuit protection must be followed to reduce the risk of fire or electric shock
16. F DRAIN HOT GAS DEFROST SUPPLY LOW TEMP SUCTION LOW TEMP LIQUID LIQUID SOLENOID S4A OR 84 THERMAL EXPANSION VALVE PILOT SOLENOID VALVE S8 OR HS8 GAS POWERED SUCTION STOP VALVE CK2 OR HCK2 DEFROST RELIEF REGULATOR W WIDE OPENING FEATURE FOR EQUALIZING A4AB OR 4 HOT GAS SOLENOID S4A OR HS4A SOFT START HOT GAS SOLENOID S8 OR HS8 RECOMMENDED FOR EVAPORATORS OF 15 TONS OR GREATER COOLING CAPACITY HOT GAS FLOW SATURATED LIQUID FLOW SUPERHEATED VAPOR FLOW DEFROST PRESSURE REGULATOR OPERATES WIDE OPEN DURING NORMAL OPERATION AND OPERATED AS REGULATOR DURING DEFROST 26 Figure 13 HOT GAS DEFROST PIPING GRAVITY FLOODED EVAPORATOR HAND EXPANSION VALVE GLOBE VALVE GAS POWERED SUCTION STOP VALVE 4 x UNIT COOLER SOLENOID VALVE DEFROST PRESSURE REGULATOR 7 2 CHECK VALVE COOLING COIL STRAINER BLOW OFF DRAIN HGD HOT GAS DEFROST SUPPLY LTS LOW TEMP SUCTION LTL LOW TEMP LIGUID HOTGASLOOP A LIQUID SOLENOID 843 OR HS4A B DEFROST RELIEF REGULATOR W WIDE OPENING FEATURE FOR EQUALIZING A4AB OR HA4AB GAS POWERED SUCTION STOP VALVES 2 OR HCK2 D HOT GAS SOLENOID S4A OR HS4A E SOFT START HOT GAS SOLENOID S8 OR HS8 RECOMMENDED FOR EVAPORATORS OF 15 TONS OR GREATER COOLING CAPACITY F PILOT SOLENOID VALVE S8 OR Hs8 HOT GAS FLOW SATURATED LIQUID FLOW SATURATED LIQUID amp VAPOR FLOW 27 EN
17. Fans not operating correctly Liquid supply not sufficient to properly feed unit Liquid control device not open or large enough ENG00018005 Rev 10 6 15 Adjust timer for more defrost cycles Adjust for increased defrost duration Adjust pressure regulator back pressure regulator for increased pressure Check condenser fans pumps for proper operation Replace timer regulator Consider some form of air moisture infiltration mitigation i e dock conditioning air curtains improved doors Cycle fans off during defrost Check defrost timer or other fan control device for proper operation Clean drain line Adjust as necessary Adjust as necessary Repair or replace as necessary Repair or replace as necessary Add additional hot gas piping support Increase hot gas flow to drain pan See Symptom 4 below Relocate as necessary Adjust as necessary Increase duration of each defrost cycle Check fans and fan motors for proper operation Replace or repair as needed Increase refrigerant supply to unit cooler Check strainers expansion valves etc Correct or replace as necessary m Ice accumulating on ceiling above evaporator or in air section or around motors fans and fan venturis Elevated Room Temperature Frequent Fan and or Motor Failure Insufficient Airthrow Defrost cycle time too long overcooking the unit Too many defrosts cycles during a 24 hour period
18. G00018005 Rev 10 6 15 Table 8 Recommended Water Defrost Temperatures Room Temperature Water Temperature 20 F to 30 F 6 7 C to 1 1 C At least 50 F 10 C 30 F to 32 F 1 1 C to 0 At least 45 F 7 2 C 32 F 0 C and up At least 40 F 4 4 C 7 5 Regulating Water Flow Rate 7 5 1 Water flow rate is controlled by adjusting the balancing valve at each unit Adjust flow rate to fully saturate the coil fin surfaces in defrost water making sure not to overflow the distribution pan which can result in undesirable splashing In some areas the water pressure may become very low during daytime hours due to usage in the same building or neighborhood In such instances it may be necessary to set the timer to defrost when adequate water pressure Is available Proper water distribution will require a water supply pressure of around 10 psi at the coil inlet connection 8 WATER AND HOT GAS DEFROST OPERATION 8 1 Condition of Operation This defrost may be used in any freezer which is routinely completely shut down and cleaned during defrost Such operation will eliminate ice buildup on coil blocks and drainpans This defrost cannot be used for continuous operation sequential defrost freezers running below freezing Please consult factory for more information 8 2 Sequence of Water and Hot Gas Defrost Operation 8 2 1 Follow guidelines for water AND hot gas defrost as detailed above 8 2 2 Se
19. G00018005 Rev 10 6 15 Figure 14 ELECTRICAL DIAGRAM MOTORS Three Phase Motor Single Phase Motor Capacitor Internal 28 ENG00018005 Rev 10 6 15 29 ENG00018005 Rev 10 6 15 COLMAC COIL Manufacturing Inc Colmac reserves the right to change product design and specifications without notice For more information on Colmac products call us at 1 800 845 6778 or visit us online at WWW COLMACCOIL COM
20. HRAE Refrigeration Handbook or other industry publications Coil connections are copper sweat connections 3 2 Hot Gas Defrost Piping 3 2 1 With this method of defrost some of the hot discharge gas from the compressor is routed into the evaporator instead of the condenser During hot gas defrost the coil temperature should be high enough to melt frost and ice on the coil but low enough so that heat and steam loss to the refrigerated space are minimized ENG00018005 Rev 10 6 15 e 3 2 2 Only 1 3 of the evaporators in a system should be defrosted at one time Example if total evaporator capacity is 100 tons 352 kW then evaporators with no more than 33 tons 116 kW of capacity should be defrosted at once Consult factory if your system does not permit this 3 2 3 Suggested methods of piping can be seen in Figure 10 thru 13 To maintain uninterrupted gas flow and a clear fully drainable condensing surface hot gas is always fed through the evaporator from the top down For a bottom feed coil this involves feeding the suction header with hot gas as is seen in Figure 10 For a top feed coil like in a Top Feed Recirculated or a Direct Expansion evaporator the liquid header distributor is fed with hot gas This can be seen in Figure 11 for Top Feed Recirculated and in Figure 12 for Direct Expansion Figure 13 shows hot gas piping for gravity flooded evaporators 3 2 4 Colmac Coil recommends the use of forward cycle fo
21. aps should be located in a warm area outside of the refrigerated space Any traps or extensive lengths of pipe located outdoors must be heated and insulated to prevent freeze up Any such heater should be connected for continuous operation Standard industry practice is for 20 Watts linear foot of pipe 0 F 17 8 C and 30 Watts linear foot of pipe 20 F 28 9 Drainpan and drain lines should be inspected and cleaned routinely See the Troubleshooting chart for information regarding the diagnosis of freezing drainpans and drain lines 3 5 Connection Sizes 3 5 1 Refrigerant defrost supply and defrost drain connection sizes are pre determined by the factory and the customer Connection sizes are automatically selected through the use of our proprietary Coldware unit cooler and tower coil selection software More information on connection sizing can be found in the ASHRAE Refrigeration Handbook 4 ELECTRICAL 4 1 Standard motors for SPR tower units do not include internal thermal overload protection except on some fractional horsepower motors consult factory for more information Motors will usually require external overload protection 4 2 Select feeder circuit protection branch circuit protection motor contactors overload relays and wire sizes in accordance with applicable local and national codes 4 3 Field wiring connections are made to individual motors through waterproof non metallic junction boxes typically f
22. efrigerant from coil for a period at least equal to 15 minutes Any liquid refrigerant that may remain in the coil during defrost will greatly reduce the effectiveness of the defrost operation Evidence of residual liquid refrigerant during defrost can be seen in the form of uneven melting or the absence of melting on the lower tubes of the evaporator coil 11 ENG00018005 Rev 10 6 15 Stop fan motors Open water valve for the necessary time of defrost Allow water to drain from fins Bleed evaporator pressure back down to normal suction pressure otart refrigeration to cool the evaporator Restart fan motors 7 3 Setting Water Defrost Timer 7 3 1 Instructions for adjustment of Defrost Timer should be shown the Timer User s Manual 7 3 2 Time periods should be set as follows The delay period for pump down and fan stoppage is approximately 1 minute With very large coils where time for pump down after shutting the refrigerant solenoid valve may be longer the delay period may be longer Set the delay accordingly Set the water spray to five minutes initially In actual practice it may take as little as three minutes to clear frost from the coil and only in rare instances would it take as long as fifteen minutes Additional time may be required for washdown please check with USDA guidelines Actual defrost times must be determined from careful observation of defrost operation and adherence to the previously m
23. entioned guidelines Frost is usually heaviest on the air entering side of the coil and inspection of fins on this side can usually be used to determine if complete defrost has occurred Periodic observation of the defrost cycle throughout the year is necessary to maintain a properly operating defrost system If more than fifteen minutes is required to completely remove frost it is an indication that something may be wrong such as inadequate water supply Set drain period for two minutes This should be ample time for water to drain off of the coil before starting up the fans The frequency of defrosting will vary greatly with each product Please check with your freezer manufacturer for defrost information NOTICE Once frost turns to ice the amount of time required to melt increases Incomplete defrosting may allow excessive ice to build up which could damage the machinery Allowing ice to build up on the fan blades will result in excessive vibration which could lead to catastrophic failure It is imperative that the end user inspect the unit coolers regularly for proper defrosting Manual defrosting may be required to remove ice buildup 7 4 Specifying Water Defrost Temperature 7 4 1 Adequate temperature of the water defrost supply must be maintained throughout the defrost to guarantee adequate defrost under varying room temperature conditions Recommended water temperatures as a function of room temperature are found in Table 8 12 EN
24. ger pipe Table 2 Recommended Pipe Size Water Defrost Supply PS inches GPM GM Ls _ t 3107 ma 80015 151022 2 2310 40 248 41170 3 7110130 1311259 Based on pressure loss of 1 to 4 ft 100 ft 100 to 400 Pa m ees Nr ao Sr ENG00018005 Rev 10 6 15 Table 3 Equivalent Length of Water Defrost Pipe Fittings Feet Pipe Size PS inches 1 112 2 212 4 _ Seis 160 mo 90 Elbow 52 66 74 85 93 110 120 190 170 pio Coupling or Gate Vave 08 12 15 17 19 25 Add equivalent length of all fittings to length of same straight pipe to obtain total length for use on Table 8 Table 4 Pressure Loss Due to Elevation Elevation S5 7 12 6 35 6 _ 5 Water Defrost Recommended Drain Line Sizes water Flow 5 25 sz e ss Pipe Size IPS inches 6 Water Capacity Sch 40 Pipe 2 5 15 2 30 50 _ 1 e 2 278 339 45 _ 259 60 741 858 1065 140 M s 2276 8916 4072 4677 S54 4 8268 987 For SCH 40 steel pipe Multiply psig values by 0 86 for PVC or Copper Pipe Notes e Ifthe water supply pressure is
25. he system should be periodically checked for proper defrosting and defrost timing due to variations in the quantity and pattern of frost Frost accumulation is dependent on the following temperature of the space type of product stored product loading rate traffic moisture content of air entering conditioned space etc It may be necessary to periodically adjust number of defrost cycles or duration of each defrost cycle to accommodate these varying conditions 11 1 2 Every 6 months Check refrigeration system for charge level oil level and any evidence of leaks e Tighten all electrical connections Check operation of control system and proper functioning of defrost solenoids drain line heaters thermostats etc Check that all safety controls are operating appropriately 11 2 Evaporator Maintenance Schedule recommended maximum time periods 11 2 1 Every 6 months or as required by USDA guidelines Clean the coil surface Inspect defrost drain pan Clean if necessary Check for proper drainage For Water Defrost inspect water defrost distribution pans Clean if necessary Inspect all insulated supply and drain lines Check all wiring Check all motors and fans tightening when necessary all motor mounting bolts and fan set screws NOTICE Do not use alkaline detergents on Aluminum coil surfaces as corrosion may result and cause refrigerant containment failure 11 3 Replacement Parts 11 3 1 Replacement part
26. ing Installation 2 3 1 Due to the large number of freezer configurations it is not feasible to detail all of the flashing installation details in this installation manual Each tower coil order however includes a copy of custom flashing assembly drawings Each flashing part is labeled with a letter which corresponds to its actual installation location on the field assembly drawings If these drawings cannot be located with your unit please consult factory 2 4 Defrost Selection 2 4 1 Determination of defrost should be based on several variables Energy costs availability of sufficient supply of water or hot gas system first cost considerations and last but not least the refrigerated spaces operating temperature Air defrost can certainly not be applied in cold storage applications with temperatures below 40 F Likewise the use of a hot gas system in a 42 F 5 6 C room may be overkill Table 1 shows recommended guidelines for defrost system selection relative to refrigerated room temperature ENG00018005 Rev 10 6 15 e Table 1 Recommended Room Temperature Ranges for Different Defrost Types Hot Gas Water Water and Hot Electric Air Temperature mange Defrost Gas Defrost Defrost Low Temp lt 20 F 6 7 C Medium Temp lt 40 F and gt 20 F 6 7 YES High Temp gt 40 F 7 2 C Not recommended for use on sequential defrost freezers or continuous operation freezers Batch processes on
27. ing conditions defrost duration can typically last anywhere from 12 to 20 minutes and in most cases should never exceed 30 minutes Actual defrost times must be determined from careful observation of defrost operation and adherence to the previously mentioned guidelines Frost is usually heaviest on the air entering side of the coil and inspection of fins on this side can usually be used to determine if complete defrost has occurred Periodic observation of the defrost cycle throughout the year is necessary to maintain a properly operating defrost system NOTICE Once frost turns to ice the amount of time required to melt increases Incomplete defrosting may allow excessive ice to build up which could damage the machinery Allowing ice to build up on the fan blades will result in excessive vibration which could lead to catastrophic failure It is imperative that the end user inspect the unit coolers regularly for proper defrosting Manual defrosting may be required to remove ice buildup 7 WATER DEFROST OPERATION 7 1 Condition of Operation Water Defrost can be used for Medium Temp and High Temp installations only within the range of standard municipal water temperatures Special considerations may be made for operation at less than Medium Temp conditions if elevated water temperatures are used Consult factory for clarification 7 2 Sequence of Water Defrost Operation otop refrigeration by closing liquid solenoid Pump down liquid r
28. l during defrost will greatly reduce the effectiveness of the electric defrost operation Evidence of residual liquid refrigerant during defrost can be seen in the form of uneven melting or the absence of melting on the lower tubes of the evaporator coil Stop fan motors Energize power to electric defrost heating elements for the necessary time of defrost De energize power to heating elements when defrost is complete Start refrigeration to cool the evaporator Restart fan motors 9 3 Setting Electric Defrost Timer Time periods should be set as follows Length of defrost should be set to the minimum time necessary to melt all frost Defrost operation beyond this point will convert liquid water to steam leading to secondary condensation and freezing on non heated areas of the tower coil and introduced unwanted heat gain into the controlled space Average defrost times can vary anywhere from fifteen to twenty minutes and in most cases should never exceed thirty minutes Actual defrost times must be determined from careful observation of defrost operation and adherence to the previously mentioned guidelines Frost is usually heaviest on the air entering side of the coil and inspection of fins on this side can usually be used to determine if complete defrost has occurred Periodic observation of the defrost cycle throughout the year is necessary to maintain a properly operating defrost system NOTICE Once frost turns to ice the amoun
29. ld not be returned to Colmac Coil without prior notification If any shortage or damage is discovered after unpacking the unit call the deliverer for a concealed damage or shortage inspection The inspector will need related paperwork delivery receipt and any information indicating his liability for the damage 2 1 2 Specified Equipment Check unit nameplate for Electrical specifications to ensure compatibility with electrical power supply Model Nomenclature and other information to match original order 2 2 Mounting and Rigging 2 2 1 The unit s must be mounted level for proper performance and refrigeration oil return 2 2 2 Individual towers may be moved with a forklift utilizing the shipping skid Once uncrated forklifts can be used to lift units into place with the lifting angle provided at the base of the coil Lifting angles should be removed upon final installation for hygienic reasons may be necessary to cut lifting angle into sections for removal See Figures 1 2 and 3 for more information 2 2 3 Unit may be lifted with hangers provided a spreader bar is used with proper attachment to the hangers See Figures 4 and 5 for more information 2 2 4 NOTICE Do not place forks or lifting straps in direct contact with drainpan 2 2 5 CAUTION Where the finned surface of the coil is exposed extreme care should be taken to avoid contact with the sharp edges of the fins to minimize the chance of injury 2 3 Flash
30. ly 3 PIPING 3 1 Refrigerant Piping 3 1 1 Ammonia e Install all refrigeration and piping components in accordance with the Ammonia Refrigeration Piping Handbook and other applicable local and national codes Piping practices for ammonia are also described in the System Practices for Ammonia Refrigerant chapter in the ASHRAE Refrigeration Handbook e Coil connections are aluminum flanges supplied with dielectric bushings gasket bolts and mating steel socket weld flanges For maintaining leak free joints be sure to support supply and return piping independent of the coil and re assemble dielectric flange unions as shown in Figure 8 Always re check flanges for tightness prior to system startup e Units equipped with bimetallic coupling connections can be welded directly to system piping after removal of the factory welded cap Remove cap so that at least 4 of the connection stub remains Do not weld within 4 of the bimetallic coupler see Figure 9 Note Evaporators with liquid feed orifices for liquid overfeed must have liquid refrigerant supplied to the coil inlet at a pressure 5 psig 35 kPa above saturated suction pressure and at a temperature not exceeding 30 F 1 1 above saturated suction temperature Please consult factory if conditions exceed the aforementioned recommendations 3 1 2 Halocarbon Use good practices as described in the System Practices for Halocarbon Refrigerants chapter in the AS
31. olume may be found on the unit submittal drawing Water flow to the unit water distribution pans is metered by the water distribution header The water distribution pans can be easily removed for cleaning and should be cleaned routinely A slope of 1 2 in per foot is recommended for all supply lines to maintain adequate drainage 3 3 3 For normal conditions Table 2 may be used to select water supply sizes However if supply water pressure is lower than 30 psig 207 kPa then the supply piping should be sized larger 3 3 4 The following procedure should be used when sizing supply water piping Choose a preliminary pipe size from Table 2 List the equivalent lengths of all fittings and valves given in Table 3 Add the sum of all equivalent lengths to the lengths of all straight pipe runs Divide the total length from step 3 by 100 Obtain the Pressure Loss per 100 feet of pipe from Table 6 Multiply this by the number obtained in Step 4 This is the pressure loss through the pipe valves and fittings due to length and flow impedances List the change in elevation is up is down of all vertical pipe runs and determine pressure losses in pipe from the gain in elevation from Table 4 The sum of Step 5 Step 6 plus a 5 psig allowance is the total pressure loss through pipe valves and fittings and must not exceed the water pressure in the supply main If it does exceed supply pressure recalculate steps 2 though 7 with a lar
32. oplets on the coil restart the fans 6 4 2 Recirculated Top Feed and Direct Expansion Evaporators See Figure 11 and 12 Close Liquid Solenoid and continue operating fan motors Pump down liquid refrigerant from coil for a period of approximately 15 minutes or as long as required Any cold liquid refrigerant remaining in the coil at the beginning of defrost will greatly reduce the effectiveness of the hot gas defrost operation Evidence of residual liquid refrigerant can be seen in the form of uneven melting or the absence of melting on the lower tubes of the evaporator Coil Stop fan motors Open Hot Gas Pilot Solenoid to close Gas Powered Suction Stop Valve On Coils of 15 tons cooling capacity and larger open Soft Start Hot Gas Solenoid to gradually bring coil up to near defrost pressure Open Hot Gas Solenoid to start defrost Duration of defrost should be long enough to clear coil and pan Extending the defrost period longer than this is not necessarily better Close Hot Gas Solenoid and Soft Start Hot Gas Solenoid if applicable to end defrost Energize the Defrost Relief Regulator to the wide open position to gradually bring the evaporator back down to suction pressure equalize Close Hot Gas Pilot Solenoid to open the Gas Powered Suction Stop Valve At the same time de energize the Defrost Regulator Valve Open the Liquid Solenoid to start cooling the coil After a delay to refreeze remaining water droplets on the coil
33. or unobstructed airflow See Symptoms 1 4 above Purchase optional airthrow straighteners from evaporator manufacturer Check fans and fan motors for proper operation Replace or repair as needed Increase fan speed 17 Figure 1 REMOVE COIL FROM SKID STEP 2 LIFT COIL FROM SKID WITH FORKLIFT OR CRANE SEE CRANE RIGGING BELOW STEP 1 V REMOVE LAG BOLTS HOLDING COIL TOWER TO WOOD SHIPPING SKID Figure 2 MOVING COIL TOWER WITH FORKLIFT 2 J 7 E 1 E FORKLIFT LIFTING ANGLE
34. ound on the face of the fan box 4 4 Basic motor wiring diagrams are shown in Figure 14 ENG00018005 Rev 10 6 15 4 5 Defrost termination and fan delay switches are provided return end of the cooler Sensing bulbs are factory installed on a refrigerant circuit return bend The maximum operating temperature for this control device is 30 F 5 GENERAL OPERATION 5 1 Before Startup Make sure unit voltage agrees with supply voltage Make sure system is wired correctly Check torque on all electrical connections Make sure all piping is done completely and in accordance with the guidelines laid out in this as well as in accordance with standard good practice Make sure that liquid supply suction and hot gas supply as applicable service valves are open Make sure unit is mounted securely and is level Make sure that all fan set screws are tight Check drainage of drain pan and drain piping by pouring water into drainpan Check water defrost distribution see Regulating Water Flow Rate Water Defrost units only 5 2 After Startup Check the compressor for possible overload immediately after start up Check fan rotation of all fans to make sure air is moving in proper direction Check the air unit operation for proper refrigerant charge Heavy moisture loads are usually encountered with non packaged products This will cause rapid frost buildup on the unit During the initial opera
35. r hot gas defrost With this method hot gas is piped in series through the tower coil first through the hot gas drainpan loop and then through the coil This method requires the use of a third line to the air unit to supply hot gas All of the piping diagrams mentioned in the previous paragraph show a forward cycle implementation Consult the Factory for information regarding reverse cycle hot gas defrost 3 2 5 For evaporators with cooling capacity 15 tons and greater a soft start solenoid valve is recommended See Figures 10 through 13 Soft Start uses a secondary smaller solenoid capable of letting a reduced amount of hot gas into the defrost system at the beginning of defrost while the main hot gas solenoid remains closed Once the system is up to a pre designated pressure 40 psig the main hot gas solenoid is opened allowing the system to approach it s normal operating pressure The Soft Start system eases the tower coil into the defrost cycle limiting unwanted problems like check valve chatter pipe movements and most of all liquid hammer This system is particularly useful on larger systems 3 2 6 Hot Gas piping located in cold spaces should be insulated as well as all Hot Gas piping located outdoors in cold climates 3 2 7 The amount of hot gas supplied will depend on the inlet pressure of the hot gas and the capacity of the tower coil 3 2 8 Ammonia Hot gas is typically supplied to evaporators by one of two methods
36. s which are covered under the conditions of Colmac Coil s warranty see Limited Warranty will be reimbursed at the part cost only For replacement parts warranted or otherwise contact Colmac Coil directly When contacting Colmac Coil with the explanation of failure have the complete model number serial number date of installation and date of failure at hand 15 ENG00018005 Rev 10 6 15 mn 12 TROUBLESHOOTING SYMPTOM POSSIBLE CAUSE POSSIBLE SOLUTION 1 Coil not clearing of frost during defrost cycle 2 1 building in drainpan 3 Uneven coil frosting Insufficient number of defrost cycles Insufficient time for each defrost cycle Hot Gas refrigerant pressure too low Defective timer or pressure regulator Excessive air moisture infiltration resulting in unreasonably high frost load Fan still operating during defrost Drain line plugged Drain line not sloped as required Unit Cooler not level Drain line heater not operating adequately Defective defrosting timer thermostat pressure regulator Hot Gas Piping not adequately supported forcing hot gas loop away from drainpan Improper piping and or inadequate flow of hot gas to pan Steam created during defrost is condensing above unit and dripping freezing onto unheated areas of evaporator Unit Cooler located too close to door or other room opening Unit Cooler not level causing uneven loading Defrost cycle time too short
37. t of time required to melt increases Incomplete defrosting may allow excessive ice to build up which could damage the machinery Allowing ice to build up on the fan blades will result in excessive vibration which could lead to catastrophic failure Itis imperative that the end user inspect the unit coolers regularly for proper defrosting Manual defrosting may be required to remove ice buildup 10 AIR DEFROST OPERATION 10 1 Condition of Operation Air Defrost can be used for High Temp installations only 10 2 Sequence of Air Defrost Operation Pump down liquid refrigerant from coil for a period at least equal to 15 minutes Any liquid refrigerant that may remain in the coil during defrost will greatly reduce the effectiveness of the air defrost operation Evidence of residual liquid refrigerant during defrost can be seen in the form of uneven melting or the absence of melting on the lower tubes of the evaporator coil Allow fans to continue operating for the necessary time of defrost Re introduce refrigerant into evaporator and re start refrigeration to cool the evaporator 10 3 Setting Air Defrost Timer Time periods should be set as follows 10 3 1 Time to defrost should be just long enough to melt all frost 14 ENG00018005 Rev B 10 6 15 e 11 MAINTENANCE 11 1 System Maintenance Schedule recommended maximum time periods 11 1 1 Every month e Check for proper defrosting and proper defrost timing T
38. tion we suggest that the frost buildup be monitored and that the unit be defrosted as often as required 6 HOT GAS DEFROST OPERATION 6 Condition of Operation Hot Gas Defrost can be used for any design criteria including Low Temp and Medium Temp 6 2 Proper hot gas defrost operation is entirely dependent on hot refrigerant latent condensation during the defrost operation This requires hot gas to be delivered to the evaporator at a saturation pressure necessary for condensation to occur during defrost Typical design hot gas saturation temperatures run between 50 F 10 C to 60 F 15 6 C Table 7 shows the equivalent saturation pressures for a variety of refrigerants required at the evaporator to accommodate this temperature range Table 7 Hot Gas Pressures for Various Refrigerants Ammonia Refrigerant EE EMEN R717 R507a 404 Dope 85 10100 psig 75 to 90 psig 10510125 psig 105 to 125 psig 688 to 791 kPa 619 to 722 kPa 826 to 964 kPa 826 to 964 kPa Pressure Evaporator 6 3 Hot Gas Supply line pressure should be maintained at less than the system condensing pressure This serves two purposes the first being decreased energy losses due to excessive heat gain and the second being that condensing pressure has a tendency to fluctuate with ambient conditions and with the load Maintaining the Hot Gas Supply ENG00018005 Rev 10 6 15 pressure at less than s
39. tting Defrost Timer Instructions for adjustment of Defrost Timer should be shown in the Timer User s Manual 8 2 3 Time periods should be set as follows Water and hot gas combination defrost is typically designed to quickly defrost and clean the coil surface at the same time Minimum defrost duration should be long enough to satisfy wash down requirements or completely defrost the coil whichever is longer Specifying Water Defrost Temperature and Regulating Water Flow Rate See water defrost section above Follow Hot Gas Defrost guidelines detailed above NOTICE Once frost turns to ice the amount of time required to melt increases Incomplete defrosting may allow excessive ice to build up which could damage the machinery Allowing ice to build up on the fan blades will result in excessive vibration which could lead to catastrophic failure It is imperative that the end user inspect the unit coolers regularly for proper defrosting Manual defrosting may be required to remove ice buildup 9 ELECTRIC DEFROST OPERATION 9 1 Condition of Operation Electric Defrost can be used for any design criteria including Low Temp Medium Temp and High Temp Applications 13 ENG00018005 Rev 10 6 15 e 9 2 Sequence of Electric Defrost Operation Stop refrigeration by closing liquid solenoid Pump down liquid refrigerant from coil for a period at least equal to 15 minutes Any liquid refrigerant that may remain in the coi
40. ystem condensing pressure helps insure constant Hot Gas pressure at the evaporator 6 4 Sequence of Hot Gas Defrost Operation 6 4 1 Recirculated Bottom Feed Evaporators See Figure 10 Close Liquid Solenoid and continue operating fan motors Pump down liquid refrigerant from coil for a period of approximately 15 minutes or as long as required Any cold liquid refrigerant remaining in the coil at the beginning of defrost will greatly reduce the effectiveness of the hot gas defrost operation and can extend the time required for defrost Evidence of residual liquid refrigerant can be seen in the form of uneven melting or the absence of melting on the lower tubes of the evaporator coil Stop fan motors Open Hot Gas Pilot Solenoid to close Gas Powered Suction Stop Valve On Coils of 15 tons cooling capacity and larger open Soft Start Hot Gas Solenoid to gradually bring coil up to near defrost pressure Open Hot Gas Solenoid to start defrost Duration of defrost should be long enough to clear coil and pan Extending the defrost period longer than this is not necessarily better Close Hot Gas Solenoid and Soft Start Hot Gas Solenoid if applicable to end defrost Open Equalizing Bleed Valve to gradually bring evaporator back down to suction pressure Close Hot Gas Pilot Solenoid to open the Gas Powered Suction Stop Valve At the same time open the Liquid Solenoid to start cooling the coil After a delay to refreeze remaining water dr
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