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START
TURN GAS SUPPLY OFF.
TURN THERMOSTAT
(CONTROLLER) TO CALL
FOR HEAT
POWER TO PC BOARD?
(24 V NOMINAL)
YES
SPARK ACROSS
IGNITER/SENSOR GAP?
YES
TURN GAS SUPPLY ON
PILOT BURNER LIGHTS?
YES
MAIN BURNER LIGHTS?
YES
SYSTEM RUNS UNTIL
CALL FOR HEAT ENDS?
YES
CALL FOR HEAT ENDS
SYSTEM SHUTS OFF?
YES
TROUBLESHOOTING
ENDS
NOTE: Before troubleshooting, familiarize yourself with the start-up and check-out
procedure.
Check line voltage power, low voltage transformer, limit controller, thermostat
(controller) and wiring.
Pull ignition lead and check spark at PC board.
Spark Okay?
YES NO
• 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.
• Check that all manual gas valves are open, supply tubing and pressures are
good, and pilot burner orifice is not blocked.
• Check electrical connections between PC board and pilot operator on gas control.
• Check for 24 VAC across PV-MV/PV terminals on PC board. If voltage is okay,
replace gas control; if not, replace PC board.
NOTE: If PC board goes into lockout, reset system. Lockout is used on L.P.G.
models.
• Check for 24 VAC across MV-MV/PV terminals. If no voltage, replace module.
• Check electrical connections between PC board and gas control. If okay, replace
gas valve or gas control operator, i.e. pilot gas valve, flow switch etc.
NOTE: IF PC board goes into lockout, reset system.
• Check continuity of ignition cable and ground wire.
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 PC board.
• Check for proper thermostat (controller) operation.
• Remove MV lead at module; if valve closes, recheck temperature controller and
wiring; if not, replace gas valve.
ELECTRICAL - ELECTRONIC IGNITION IID
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.
NO
NO
NO
NO
NO
NO
Replace the PC board.