Weil-McLain CGA25SPDN manual 11b Troubleshooting - standing pilot boilers

GOLD CGa Gas-Fired Water Boiler — Boiler Manual

11b Troubleshooting — standing pilot boilers

CHART 1 — Standing pilot — Boiler will not fire

				Is damper harness securely plugged in at both ends?
		Secure connections.
				No			Yes
	Check for loose wire connections or bad relay on
				Is 24VAC present across transformer terminals C & Y?
	transformer.
				No			Yes
Check for open thermostat, LWCO, high limit, spill switch or
rollout thermal fuse element contacts or check for loose wire				Is 24VAC present across transformer terminal C and
connections.				yellow wire on vent damper connector?
		If LWCO, spill switch or rollout thermal fuse		No			Yes
		element contacts are open, determine cause
		and correct condition. Failure to do so will
		cause severe personal injury, death or			Is vent damper rotated open?
		substantial property damage.
				No			Yes
Check/repair out of round stack section. Does vent damper				Is 24VAC present across gas valve terminals?
rotate open?
	No		Yes	No			Yes
	Replace actuator.
	Retest.					Is main flame on now?
				No			Yes
Open thermostat contacts for 30 seconds. Vent damper will
rotate to closed position. Close thermostat contacts. Vent							Retest
damper will rotate to open position. Is 24VAC present
across gas valve terminals?
				Is gas valve cock turned to ON position?
	No		Yes
				No			Yes

Check continuity of each wire in damper harness. Does continuity exist for each wire? See Table below.

No Yes

Turn gas valve cock to ON position. Retest.

Replace gas valve. Retest.

Replace damper wiring harness. Retest.

Remove damper harness from damper harness plug. TEMPORARILY install jumper between terminal 2 and terminal 5 on damper plug in boiler wiring harness. See figure, right. Does boiler fire?

No Yes

Replace gas valve. Retest.

Replace damper actuator. Retest.

Part Number 550-101-009/0107 51