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service diagnosis <br /> EFFECT OF PILOT OPERATION 2. Pilot lights,main burner will not light. <br /> ON SAFETY CONTROLS POSSIBLE CAUSE POSSIBLE REMEDY <br /> 1. A weak pilot flame may cause poor ignition or reduce 2a. Gas valve in off 2a.Turn to on position. <br /> heat on thermocouple to the'point where the automatic position. <br /> controls become inoperative,thereby shutting off gas 2b.System in lock-out 2b.Reset system. <br /> supply to main burners.This may result from a plugged mode. <br /> Orifice, dirty pilot valve Or gum filter. 2c. Cracked or broken 2c. Replace sensor. <br /> 2. Check electrical connections from the thermocouple sensor ceramic, <br /> element to the safety valve to assure good electrical 2d.Defective or loose 2d.Correct or replace. <br /> contact.Also check location of pilot flamF in relation to connections to <br /> flame sensor or <br /> thermocouple element. flame sensor lead. <br /> 2e. Incorrect gas 2e.Check and adjust if necessary to manu- <br /> pressure. facturer's recommendations. <br /> IF MAIN BURNERS DO NOT LIGHT 2f. Insufficient current 2f. Check current according to manufacturer's <br /> signal from flame recommendations and replace if necessary. <br /> 1. Check gas supply to burners. sensor. <br /> 2. Bleed air from pipe lines. 2g.Incorrect or loose 2g.Check wiring. <br /> 3. Be sure pilot is lit, correct) wiring. <br /> p y positioned and strong <br /> 2h.Poor ground to 2h.Check grounding means. <br /> -enough to ignite burner ports. ignition controller. <br /> 4. Check wiring (electric power supply)to automatic gas 2i No power to ignition 2i. Check voltage to controller and gas valve. <br /> valve. controller or gas <br /> valve. <br /> 5. If the above does not correct the condition, consult 2j. Loose limit control 2j. Check connections.Replace limit control <br /> your local gas company or local Modine factory connections or if necessary. <br /> representative. defective limit. <br /> 2k.Defective or plugged 2k. Inspect gas valve regulator. Replace if <br /> INTERMITTENT PILOT IGNITION SYSTEMS gas valve regulator. necessary. <br /> 21. Defective thermostat 21. Calibrate thermostat or replace if necessary. <br /> CAUTION or thermostat out of <br /> calibration. <br /> Do not attempt to reuse ignition controllers which have 2m.Thermostat heat 2m.Check anticipator setting and correct if <br /> been wet. Replace defective controller. <br /> anticipator necessary. <br /> incorrectly set. <br /> I Re 2n.ignition 1. Pilot will not light or stay lit. 2n.Defective i 9 Pace. <br /> controller. <br /> POSSIBLE CAUSE POSSIBLE REMEDY 2p.Blocked vent switch 2p.Refer to page 20 for instructions. <br /> la.No spark at ignitor. la.Check connections.Check for proper tripped. <br /> spark gap,cracked or broken electrode <br /> ceramic,blown controller fuse or brittle, 3. System goes into lock-out. <br /> cracked or loose high tension cable. <br /> 1b.Defective flame 1 b.Check mill-amps of sensor.Tighten loose POSSIBLE CAUSE POSSIBLE REMEDY <br /> sensor or loose connections. Replace flame sensor if 3. Refer to"Pilot will 3. Reset system.If lock-out persists,check <br /> connections to necessary. <br /> flame sensor. not light or item 1,"Pilot will not light or stay <br /> stay lit". lit". <br /> 1c. Pilot valve electrical 1c.Tighten connections. <br /> connections loose. 4. System shuts down before thermostat is satisfied. <br /> 1d.Defective pilot valve. 1d.Replace. <br /> le. Poor ground le.Check grounding means. POSSIBLE CAUSE POSSIBLE REMEDY <br /> connections. 4. Flame sensing 4. Check flame sensing rod,sensor ceramic, <br /> 1f. No power from 1f. Check transformer voltage on secondary <br /> circuit failure. sensor lead and connections for damage <br /> control transformer. side for 25v. or loss of continuity.Replace defective <br /> elements. <br /> 1g.Spark not located in 1g.Correct or replace pilot. <br /> pilot gas stream. 5. System falls to shut off after thermostat is satisfied. <br /> 1h. Dirty or plugged 1h.Clean or replace. <br /> pilot orifice. POSSIBLE CAUSE POSSIBLE REMEDY <br /> 1i. Pilot line kinked or 1i. Correct or replace pilot line. 5a. Faulty thermostat 5a. Check thermostat and anticipator setting. <br /> obstructed. or improper heat Replace if defective. <br /> 1j. Pilot flame too low. 1j. Check pilot flame and adjust per manu- anticipator setting. <br /> facturer's recommendations. 5b.Defective ignition 5b.Replace. <br /> 1k. Flame sensor out of 1k. Reposition. controller. <br /> position. 5c.Defective gas valve. 5c. Replace. <br /> 11. Defective ignition 11. Replace. <br /> controller. If the foregoing checks do not solve the problem,consult your local gas <br /> company or local Modine factory representative. <br /> When servicing,repairing or replacing parts on these units always give the <br /> complete Model Number,Power Code Number,Control Code Number and <br /> Serial Number from the unit rating plate. <br /> See page 27 for Model Number and Serial Number Designations. <br /> Page 23 <br />