TROUBLESHOOTING - ELECTRICAL
(ELECTRONIC IGNITION IID)
Intermittent Pilot System
HONEYWELL S8600
WARNING
HIGH VOLTAGE
For qualified Technicians ONLY
NOTE: Some heaters may be equipped with an ignition module that shuts off pilot gas if pilot fails to light. To reset, interrupt power to heater.
START
TURN GAS SUPPLY OFF.
TURN THERMOSTAT
(CONTROLLER) TO CALL
FOR HEAT
POWER TO MODULE
(24 V NOMINAL)?
YES
SPARK ACROSS
IGNITER/SENSOR GAP?
YES
NO 
NO
NOTE: Before troubleshooting, familiarize yourself with the
Check line voltage power, low voltage transformer, limit controller, thermostat (controller) and wiring.
Pull ignition lead and check spark at module.
If spark is okay:
•Check ignition cable, ground wiring, ceramic insulator and gap, and correct.
•Check boot of the ignition cable for signs of melting or buckling. Take protective action to shield cable and boot from excessive temperatures.
If not, replace module.
TURN GAS SUPPLY ON PILOT BURNER LIGHTS?
YES
SPARK STOPS WHEN
PILOT IS LIT?
YES
MAIN BURNER LIGHTS?
YES
SYSTEM RUNS UNTIL CALL FOR HEAT ENDS?
YES
NO |
| • Check that all manual gas valves are open, supply tubing and pressures are good, |
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| and pilot burner orifice is not blocked. |
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•Check electrical connections between module and pilot operator on gas control.
•Check for 24 Vac across
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| NOTE: If S8600H goes into lockout, reset system. Lockout is used on propane | |
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| models. | |
NO |
| • | Check continuity of ignition cable and ground wire. |
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| • | Clean flame rod. |
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| • | Check electrical connections between flame rod and module. |
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| • | Check for cracked ceramic flame rod insulator. |
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| • | Check that pilot flame covers flame rod and is steady and blue. |
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| • | Adjust pilot flame. |
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| • | If problem persists, replace module. |
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| • | Check for 24 Vac across |
NO |
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| • | Check electrical connections between module and gas control. If okay, replace | |
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| gas valve or gas control operator, i.e. pilot gas valve, flow switch etc. |
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NOTE: IF S8600H goes into lockout, reset system.
NO | • Check continuity of ignition cable and ground wire. |
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NOTE: If ground is poor or erratic, shutdowns may occur occasionally even though operation is normal at the time of checkout.
•Check that pilot flame covers flame rod and is steady and blue.
•If checks are okay, replace module.
CALL FOR HEAT ENDS SYSTEM SHUTS OFF?
YES
NO 
•Check for proper thermostat (controller) operation.
•Remove MILLIVOLT lead at module; if valve closes, recheck temperature controller and wiring; if not, replace gas valve.
TROUBLESHOOTING ENDS
37
