Honeywell L404A-D User's Manual
Contents
1. FINISH Gray APPROVALS Underwriters Laboratories Inc listed L404A B C DF L604A L M only file no MP466 vol 10 guide no MBPR Canadian Standards Association certified LA04A B C DF L604A L only file no LR1620 guide no 400 E 0 Scale Plate psi 0 to 15 2 to 15 5 to 50 3103 5 5 to 150 10 to 150 20 to 300 1 4 to 20 7 TABLE 2 CONVERSION TABLE psi to kPa Subtractive Differential Operating Range Scale Plate psi Equivalent 310103 aowa Sd SSC OC 7 to 10 3 69 to 1034 10 to 22 138 to 2068 15 to 40 1 0 to 20 to 50 l4 REPLACEMENT PARTS 129178 Thermoplastic Cover 14026 Steam Trap siphon loop 1 4 in black iron pipe Necessary for boiler installations ACCESSORIES 33312B Knurled Adjustment Knob with setscrew fits on main scale pressure adjusting screw 4074B WJ Limit Stop Assembly to limit set point ranges includes 129564 Range Stop 107194 Range Stop Screw and 23466 Wrench 1to6 07 to 4 Tto4l 2 to 6 14 to 4 14to4 4to 12 3 to 8 28 to 83 4 to 1 0 41 to 97 Sto 14 8 to 16 6 to 1 1 55 to 110 7 to 1 5 69 to 152 103 to 276 138 to 345 t to Fig 1 Mounting dimensions of the L404A B C D F and L604A L M Pressuretrol Controllers in in mm LA04A D F L6O4A L M 4 1 2 1143 COVER _ _ _ 4 11 32 110 3 CASE eee at 115 18 49 2 ame we 1 51 54 49 8 A RESET2. Fig 2 Right and wrong mounting of a steam trap siphon loop with approximate dimen sions in in mm PRESSURE PRESSUR GAUGE CONTROLLER STEAM TRAP SIPHON LOOP CORRECT 4 1 2 TO 5 1 2 114 3 TO 139 7 A 1 4 IN BLACK IRON PIPE WITH 1 4 18 NPT EXTERNAL TRHEADS ON BOTH ENDS BEND THE STEAM TRAP SIPHON LOOP TO LEVEL THE CONTROLLER M8034 Make ali pipe connections in accordance with approved standards Use only a small amount of pipe compound to seal the connection joints Excess pipe compound can clog the small hole in the fitting and prevent the controller from operating properly To avoid leaks and damage to the case use a parallel jaw wrench on the controller s hexagonal fitting Do not tighten the controller by hand by holding the case i Leveling A controller with a mercury switch must be accurately leveled for proper operation It is level when the leveling indicator Fig 11 hangs freely with its pointer directly over the index mark inside the back of the case Level the controller by carefully bending the steam trap siphon loop Mounting Alongside a Pressure Gauge To mount the controller alongside a pressure gauge Fig 2 remove the gauge In its place install a steam trap siphon loop with a tee on top Using elbows and pipe nipples mount the controller and pressure gauge on the ends of the tee Level the controller after installation LA N1aSN 1A L404A D F LE
3. differential 85 60 10to150 66to10 6 69 to 1034 i 225 15 8 20 t0 3004 1 4to21 0 138 to 2068 7 500 35 2 L404D spst makes 2 to 15 14 to 1 0 14 to 103 manual reset wt 35 345 ircuit 10to150 66to 10 69 to 1068 fixed subtractive differential 225 15 8 1550 50 35 345 85 6 0 225 15 8 500 35 2 5 85 spdt snap acting 14 to 1 0 14 to 103 14 to 41 switch makes 5 to 50 35 to 3 5 34 to 345 41 to 97 R W breaks R B 10 to 150 66 to 10 69 to 1034 60 to 152 20to 3004 1 4to21 0 138 to 2068 138 to 345 14 to 41 28 to 82 56 to 1 10 1 04 to 2 76 14 to 4i 27 to 83 55 to 110 103 to 276 2 to 15 14 to 1 0 14 to 103 5 to 50 35 to 3 5 34 to 345 10 to 150 66 to 10 69 to 1034 20 to 300 1 4to21 0 138 to 2068 spdt circuit 2to 15 14 to 1 0 14t0 103 makes R W l 10to 150 fixed 3 5 psi 24 1 kPa 15 8 1550 Scaleplates are marked in both psi and kg cm b Model available with special fixed low differential Switch rated for 0 5A at 120 Vac 1 404A B and L604A models are available with 1 to 6 psi midscale subtractive differential in 2 to 15 psi models d Brass bellows replaces stainless steel diaphragm Not suitable for use with ammonia oxygen or other corrosive materials Model available with minimum operating pressure of 1 25 psi 0 09 kg cm or 8 62 kPa and minimum subtractive diffe
4. 04A LM INSTALLATION Mounting on a Boiler If it is not convenient to mount the controller alongside the pressure gauge install a steam trap siphon loop in the fitting provided by the boiler manufacturer If there is no fitting mount the steam trap at a location recommended by the boiler manufacturer Screw the controller directly to the steam trap and level the controller Mounting at a Remote Location If there is excessive vibration at the boiler that can adversely affect the operation of the controller mount the _ controller at a remote location All piping from the boiler must be suitable and solidly mounted The piping must be properly pitched to drain all condensation back to the boiler A steam trap siphon loop must be mounted be tween the remote piping and the controller Level the controller after installation Supervision of Atomizing Medium Pressure Air or Steam L404B When air or steam is used as an atomizing medium in an oil burner system authorities having jurisdiction approval bodies and codes often require a low limit to prevent opening the main oil valve until sufficient atomizing pres sure is present and to shut down the system when the atomizing pressure falls too low The L404B is recommended for this application It makes a circuit when the pressure rises to the set point and breaks when the pressure falls to the set point minus the differential Fig 10 WIRING 1 Disconnect the power sup
5. 1 W BREAKS R2 8 ON PRESSURE RISE TO SETPOINT SPOT SWITCH ACTION WITH JUMPER INSTALLED on OTHERWISE TWO ISOLATED SPST SWITCHES Fig 5 L404 used as a limit or as an operating controller SPST CONTROLLER TE E FLAME HOT ES 3 SAFEGUARD CONTROL SUPPLY MOTOR OR OTHER LOAD L2 2 il PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED HIGH LIMIT L404A OR C BREAKS WHEN PRESSURE RISES TO SETPOINT LOW UMIT L4048 BREAKS WHEN PRESSURE FALLS TO SETPOINT MINUS DIFFERENTIAL OPERATING CONTROLLER L404A BREAKS WHEN PRESSURE RISES TO SETPOINT AND MAKES AGAIN WHEN PRESSURE FALLS TO SETPOINT MINUS DIFFERENTIAL Masas re ee Fig 6 L404 with a low voltage relay LOW VOLTAGE RELAY L404 HAT POWER cafka SUPPLY 4 7 z THERMOSTAT PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS DEGUHED M8940 s P Fig 7 L404F L604A jumper instailed used as a high limit with an alarm circuit FLAME SAFEGUARD OTHER LOAD A PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED J BREAKS A TO W AND MAKES ATO B WHEN PRESSURE FALLS TO SETPOINT MINUS DIFFERENTIAL ene L404A D F L604A L M INSTALLATION Fig 8 L404F L604A with jumper installed or L604M used as a low limit with an alarm circuit SPOT CONTROLLER HIGH LIMIT FLAME SAFEGUARD CONTROL MOTOR OR OTHER LOAD POWER SUPPLY A PROVIDE DISCONNEC
6. ESSURE RISE DIFFERENTIAL SETTING BREAKS R1 W MAKES R2 8 J 22sec AND LEOA MANUAL RESET MODELS HAVE A SMALL FIXED AS ERENTIAL THEY CAN BE MANUALLY RESET WHEN THE PRESSURE FALLS TO THE MAIN SCALE SETPOINT MINUS THE DIFFERENTIAL A L604M HAS A SMALL FIXED DIFFERENTIAL OF 3 6 PSI 0 25 kg cm OR 24 1 kPa Meg42 2 Adjust the main scale set point for the desired operating pressure by tuming the main scale adjusting screw Fig 11 on the top of the case until the main scale setting indicator is at the desired value On an 1404A B F with a 5 to 150 psi 3 to 10 3 kg cm 34 to 1034 kPa operating range or an L604A adjust the differential setting by turning the dif ferential adjusting screw Fig 11 until the differential setting indicator is at the desired value 1404C D and L604L are manual reset models see the next paragraph The L604M has a fixed differential The scaleplates are marked psi and kg cm Trip Free Manual Reset Feature L404C D and L604L only The L404C breaks the L404D makes and the L604L makes R W and breaks R B when the pressure rises to the Setting and Checkout J main scale setpoint They will not automatically return to their former positions To reset one of these controllers wait until the pressure falls to the set point minus the differential Fig 10 Then depress the manual reset lever Fig 11 and release it The controller will not be reset until you release the manual rese
7. ETN A ree pa r e a E n o e erme ee ee L404A D F L604A L M Pressuretrol Controllers 1404 and L604 Pressuretrol Controllers are line voltage pressure controllers that provide oper ating control automatic limit protection ormanual reset limit protection for pressure systems of up to 300 psi 21 1 kg cm or 2068 kpa Ne W Can be used with steam air non combustible gases or fluids non corrosive to the pressure sensing ele ment E Stainless steel diaphragm except 300 psi 21 1 kg cm 2068 kPa models also allows use with am monia oxygen distilled water and similar media W LA04B is recommended for supervision of atomiz ing medium pressure in oil burner systems E Models are available with spst spdt or dpst switch ing and in variety of operating ranges Z Dustproof trouble free mercury switches all mod els except L404F which has snap acting switch W Automatic reset models have adjustable subtractive differential except L604M E Trip free mechanism on manual reset models as sures that limit function of controller cannot be defeated by jammung reset lever E Screw adjustments made on top of case W Scaleplates marked in English psi and Metric kg cm units W L404F models available with Eurdp an enclosure British Standard Pipe Threads ground screw and scaleplates marked in kg cm and either psi or kPa E Clear plastic cov
8. LEVER ON MANUAL RESET MODELS ONLY a 2 3 4 69 9 _ _ 116 w 27 0 1916 i A og V2 127 E 2s R vn eee 98 4 94 5 431 32 126 2 K tate 20 4 A oe o ma ane 48 X21483 2A OIA I t 1 1 6 1 416 30 2 21 0 wenn 1 1 2 38 1 A THIS DIMENSION 1S 4 27 32 IN 123 0 MM ON L604 MODELS WITH A 2 TO 15 PSI 14 TO 1 0 laytan 14 TO 103 kPa OPERATING RANGE AND 5 3 4 IN 148 A MM ON L604 MODELS WITH A 20 TO 300 PSI 1 4 TO 20 7 kem 138 TO 2068 kPa OPERATING RANGE A ONLY ON L804 MODELS WITH A 2 TO 15 PSI 14 TO 1 0 layer 14 TO 103 KPa OPERATING RANGE i Maax3 AN 9 T5010 AQ4A D F L604A L M INSTALLATION Installation _ WHEN INSTALLING THIS PRODUCT 1 Read these instructions carefully Failure to follow them could damage the product or cause a hazardous condition 2 Check the ratings given in the instructions and on the product to make sure the product is suitable for your application 3 Installer must be a trained experienced flame safe guard control technician 4 After installation is complete check out product operation as provided in these instructions N CAUTION hataieriarn ae E 1 Disconnect power supply before beginning in stallation to prevent possible equipment dam age or electrical shock 2 When using the controller with a compressor installa dampening device such as aneedle valve heade
9. T MEANS AND OVERLOAD PROTECTION AS REQUIRED BREAKS A TO 8 ANO MAKES A TO W WHEN PRESSURE RISES TO SETPOINT E Fig 9 L404F or L604 with jumper installed controlling an M644B motor LINE VOLTAGE TWO POSITION MOTOR CLOSED LOW FIRE OPEN HIGH FIRE POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED A BREAKS R TO 8 AND MAKES R TO W WHEN PRESSURE RISES TO SETPOINT M8939 404A D F L604A L M ETTING AND CHECKOUT SETTING In all models the differential is subtractive from the main scale set point The upper operating point is deter mined by the main scale set point while the lower operat ing point is determined by the main scale setting less the differential setting The L404F and L604A with jumper installed L M have spdt switching action Operating points are shown in Fig 10 i Fig 10 L404 and L604 operating points MAIN SCALE SETPOINT SWITCH BREAKS SUBTRACTIVE DIFFERENTIAL L404A C DIFFERENTIAL SETTING A SWITCH MAKES MAIN SCALE SETPOINT SWITCH MAKES SUBTRACTIVE DIFFERENTIAL L4046 0 PRESSURE RISE DIFFERENTIAL SETTING A SWITCH BREAKS MAIN SCALE SETPOINT BREAKS P B MAKES A W SUBTRACTIVE L404F OIFFERENTIAL LG6GO04L M PRESSURE RISE DIFFERENTIAL SETTING MAKES A 8 BREAKS A W 4 MAIN SCALE SETPOINT MAKES R1 W BREAKS R2 8 SUBTRACTIVE L604A DIFFERENTIAL PR
10. ailable except where noted in Table 1 The steam trap is necessary for boiler installations SWITCH ES Mercury switch es in all models except the LA04F which has a Micro Switch snap acting switch PRESSURE SENSING ELEMENT Stainless steel dia phragm brass bellows in 300 psi 21 1 kg cm 2068 kPa models MAXIMUM AMBIENT TEMPERATURE 150 F 66 C MINIMUM AMBIENT TEMPERATURE Minus 35 F minus 37 C also refer to the note in the Location and Mounting section ADJUSTMENT MEANS Screws on top of controller case Scales are marked in psi and kPa ELECTRICAL CONNECTIONS Internal screw terminals hole in side of case for 1 2 in conduit MOUNTING MEANS Hexagonal fitting on diaphragm has 1 4 18 NPT internal threads for mounting on a pipe or steam trap siphon loop Also can be surface mounted using screws through two holes knockouts in back of case Ordering Information When purchasing replacement and modernization products from your cain wholesaler or distributor refer to the Tradeline Catalog or price sheets for complete ordering number or specify Order number TRADELINE model if desired Operating range see Table 1 Optional specifications if desired see Table 1 Replacement parts if desired Accessories if desired Aa Bf U Nn e Model without steam trap if desired and available see Table 1 N ote b If you have additional questions need further information or w
11. er on case to observe pressure set tings and switch action E Leveling indicator visible through cover E Hexagonal fitting with 1 4 18 NPT internal threads for direct mounting to 14026 Steam Trap siphon Joop W Surface mount is available using screws through holes knockouts in case backing CONTENTS SPECTAICQUONS jaicddaidadsccpasabozecesseeasaaineeinsseravases 2 Ordering Information cccccccccesccscecreeseeiees 2 nstallat On criss ciate sce teat aa ea Setting and Checkout csssssencnesssssneenneaees 8 Service Information 0 10 L Z Rev 3 95 Honeyweil Inc 1995 OOO 04A D F L604A L M 2ECIFICATIONS ORDERING INFORMATION Specifications ee i TRADELINE MODELS TRADELINE models are selected and packaged to provide ease of stocking ease of handling and maximum replacement value Specifications of TRADELINE con trols are the same as those of standard models except as noted below TRADELINE MODELS AVAILABLE L604A Pressuretrol Controllers A vailable in 2 to 15 5 to 50 10 to 150 and 20 to 300 psi 14 to 1 1 kg cm 14 to 103 kPa 4 to 3 5 kg cm 34 to 345 kPa 7 to 10 6 kg cm 69 to 1034 kPa and 1 4 to 21 0 kg cm 138 to 2068 kPa ADDITIONAL FEATURES TRADELINE pack with cross reference label STANDARD MODELS MODELS L404A D F and L604A L M Pressuretrol Con trollers See Table 1 A 14026 Steam Trap siphon loop is av
12. me eee sae ee ZERO OHMS INFINITY WHEN R 8 BREAKS AN L604 WITH JUMPER INSTALLED BETWEEN A1 AND R2 IS SHOWN AN L404F OPERATES SIMILARLY SPDT SWITCHING AN L404A B OR D HAS ONLY TWO TERMINALS SPST SWITCHING AN L 404A OR C BREAKS AND L4048 OR D MAKES WHEN THE SETPOINT IS DECREASED FAR ENOUGH f Maad4 O4A D F L604A L M AVICE INFORMATION CALIBRATION The controller was carefully calibrated during manufac turing and should not require recalibration Most calibra tion errors are caused by improper leveling The controller should be level when the pointer on the leveling indicator is directly over the index mark Fig 11 In some cases the leveling indicator may not be accurate enough The pointer may be over the index mark but the controller still may not be operating within the tolerance of its scale setting In this case carefully bend the steam trap siphon loop until the controller switches properly Service Information MAINTENANCE The cover of the controller should be in place at all times to protect the internal components from dirt dust and physical damage Routine maintenance should consist of occasional inspection and blowing or brushing away any accumulated dirt and dust To ensure proper functioning of the controller at all times perform an operational check of the entire system during routine maintenance checks oy
13. ould like to comment on our products or services please write or phone 1 Your local Home and Building Control Sales Office please check the white pages of your phone directory 2 Home and Building Control Customer Logistics Honeywell Inc 1885 Douglas Drive North Minneapolis Minnesota 55422 4386 612 951 1000 In Canada Honeywell Limited Honeywell Limit e 740 Ellesmere Road S Gates MiP2V9 International Sales and Service Offices in all principal cities of the world Manufacturing in Australia Canada Finland France Germany J epai Mexico Netherlands Spain Taiwan United Kingdom U S A L404A D F L604A L M SPECIFICATIONS TABLE 1 MODELS AVAILABLE sir on Midscale Subtractive Differential Pressure Rise Adjustable to Setpoint 14to1 0 14to103 14 to 41 3503 5 3410345 28 to 82 1271083 660 10 6 69 to 1034 56to 1 10 55toll0 225 15 8 1 4t021 0 138 to 2068 1 0410 2 76 103t0276 500 35 2 210 15d 14to1 1 1410 103 14to41 1404 OD 35 5 to 50 3503 5 24t0345 28 to 82 27 to 83 85 60 10to150 66to10 6 69to 1034 56to1 10 55to110 225 15 8 20 to 3009 1 4to21 0 138 to 2068 1 04 to 2 76 1030276 500 35 2 2 to 15 14t01 0 14to 103 manual reset 50 3 5 5to50 35t03 5 3410345 fixed subtractive
14. pending on the model of the controller An L404A or C should break an L4048 or D should make an L404F L604L M should break R B and make R W and an L604A should break R2 B and make R1 W If it makes the ohmmeter reads zero if it breaks the ohmmeter reads infinity 5 Raise the set point of the controller simulating a pressure decrease through a range greater than the differen tial The switch should break or make just the opposite of its _ action in step 4 except for the L404C D and L604L manual reset models NOTE An approximation of the differential can be made by observing the change in set point required for a resistance change from zero to infinity 6 If the controller operates improperly replace it 7 When the controller is operating properly reconnect the wires to the terminal block replace the cover and tighten _the cover screw and reconnect the power SETTING AND CHECKOUT A N CAUTION Do not put the system into service until you have satisfactorily completed all applicable tests de scribed in this Checkout section in the Checkout section of the applicable instructions for the flame safeguard control and any others required by the burner and boiler manufacturers Fig 12 Checking controller operation using an ohmmeter MAIN SCALE gausa SCREW ae ee as HS 7 4 A Hi J VADO Ea HAS a YAY ogv SETPOINT DECREASE 7
15. ply before beginning wiring to prevent electrical shock or equipment damage 2 Assume all wiring complies with applicable electrical codes ordinances and regulations Use NEC Class 1 line voltage wiring _ 3 Fornormal installations use moisture resistant No 14 wire suitable for at least 167 F 75 C when you are using the controller with a flame safeguard primary control or at least 194 F 90 C when using it with a programming control 4 For high temperature installations use moisture resis tant No 14 wire selected for a temperature rating above the maximum operating temperature 5 All models have a terminal block inside the cover Fig 3 and 4 and a 7 8 in 22 2 mm hole in one side for 1 2 in conduit cable or wires Remove the front cover by loosen ing the screw at the bottom of the main scale 6 Refer to Fig 5 through 9 for typical hookups Follow the burner or boiler manufacturer s wiring diagram if pro vided 7 Make sure the loads do not exceed the Switch Contact _ Ratings in the Specifications section 8 Replace the front cover when wiring is completed Fig 3 L404 terminal blocks and internal schematics RISE L404A C 14048 0 L404F SNAP ACTING BREAKS ON MAKE BREAKS A B PRESSURE RISE PRESSURE RISE MAKES A W ON TO SETPOINT TO SETPOINT PRESSURE RISE TO SETPOINT MOAT Fig 4 L404 terminal block and internal _ schematic L604A L604L M MAKES R
16. r or surge tank to dampen pulsations that can damage the controller or reduce its life IMPORTANT 1 Locate the controller where the ambient temperature will not exceed 150 F 66 C 2 Use pipe compound sparingly to avoid clogging the hole in the pipe or diaphragm fitting 3 Do not tighten the controller by hand by holding the case 4 Accurately level the controller for proper operation LOCATION AND MOUNTING NOTE For most accurate operation add supplemental heat to installations where the temperature falls below minus 20 F minus 29 C Never locate the controller where the temperature falls below minus 35 F minus 37 C be cause mercury in the switch freezes at this temperature When used with steam boilers always mount the con troller above the water line in the boiler A steam trap siphon loop must always be connected between the con troller and the boiler Fig 2 to prevent boiler scale and corrosive vapors from attacking the diaphragm The loop on the steam trap must always be perpendicular to the face of the controller If the loop is parallel to the controller expansion or contraction of the loop tips the controller and causes the switch to operate inaccurately The controller can be mounted 1 alongside the pres sure gauge 2 in a fitting on the boiler provided by the manufacturer 3 at a remote location in case of excessive vibration or 4 in a special mounting on a low water cutoff l
17. rential of 0 5 psi 0 035 kg cm or 3 45 kPa f Model available with special fixed low differential Switch rated for 0 5A at 120 Vac ae 1 404C D and L604L models are designated as Manual Reset 2 controllers the trip free reset mechanism does not permit the controller to function as an automatic reset device when the manual reset lever is held in the reset position The subtractive differential is fixed at the minimum value of the adjustable differential of the L404A foreach corresponding operating range h 1404F only all other models have mercury switches i l i Model available with sealed bell crank adjustment J Spst switches operate in unison spdt action when jumper is installed between R1 and R2 k Also recommended for supervision of atomizing medium pressure air or steam in an oil burner system manual reset 8 fixed subtractive differential SWITCH CONTACT RATING in amperes at 50 60 Hz Locked Rotor Noninductiv L604A L gt Locked Rotor Noninductive L604M 2 L404F snap acting does not have non inductive or de ratings D 1604A and L have also been tested and listed by Underwriters Laboratories Inc and breaking not making a load with a total rating of 9 8 A full load plus 360 VA ignition plus 250 VA pilot duty at 120 Vac k 60 2150 10 404A D F L604A L M 3PECIFICATIONS DIMENSIONS See Fig 1 See Fig 2 for mounting steam trap siphon loop WEIGHT 2 IBC 0 91 kg
18. t lever This prevents the con troller from becoming an automatic reset device if the reset lever is stuck held in or tied down Fig 11 Setting a Pressuretrol Controller DIFFERENTIAL ADJUSTING MANUAL SCREW l jena MAIN SCALE SCALEPLATES ADJUSTING A SCREW MERCURY SW DIFFERENTIAL SETTING INDICATOR aS MAIN SCALE SETTING INDICATOR DIAPHRAGM LEVELING ASSEMBLY INDICATOR A ADJUSTABLE DIFFERENTIAL ON THE L404A B F L404L WITH A 5 TO 150 PSI 0 34 TO 10 3 kg cm 34 TO 134 kPa OPERATING RANGE AND L604A MODELS ONLY A TRIP FREE MANUAL RESET LEVER ON THE L404C D AND L604L MODELS ONLY mages an CHECKOUT After the controller has is installed wired and set test it with the system in operation First allow the system to stabilize Then observe the operation of the controller while raising and lowering its setpoint Pressure should increase when the setpoint is raised and decrease when the set point is lowered Also check the make and break points of the controller If they do not agree with a separate accurately calibrated pressure gauge a slight adjustment of the scaleplate s may be necessary Use accurate pressure testing equipment when checking out the controller Do not rely on inexpensive gauges The controllers are carefully calibrated at the factory i Boiler Installation a If the controller is being used on a boiler installation test it as follows L Note the boiler press
19. ure by checking the boiler pres sure gauge To perform this test properly the boiler should have a pressure reading near the middle of the controller s main scale range 7 2 Turn the main scale adjusting screw Fig 11 until the main scale setting indicator on the controller corresponds to the boiler pressure gauge reading 3 The L404A or C should break the control circuit s automatically when the boiler pressure gauge reading equals or slightly exceeds the controller setting The L404B or D should make the circuit under the same circumstances ys The L404F L604L M should make the R W circuit and break the R B circuit under the same circumstances The L604A should make the R1 W circuit and break the R2 B circuit under the same circumstances 4 If the controller is operating properly turn the main scale adjusting screw Fig 11 until the main scale setting indicator is at the desired set point If a Controller Seems to Operate Improperly If the controller is suspected of operating improperly it may be further checked as follows Fig 12 l Disconnect all power to the controller loosen the cover screw and remove the cover 2 Disconnect the wires from the controller 3 Connect an ohmmeter between the switch terminals 4 Lower the set point of the controller simulating a pressure increase through a range greater than the differen tial The switch should either make or break de
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