Vulcan-Hart service manual Troubleshooting Guide

TROUBLESHOOTING GUIDE

SYMPTOM	CAUSE	REMEDY
Pilot does not light after	Problem with pilot valve	Check operation of pilot valve
igniter has been on
several minutes	Gas supply not purged of air	Purge gas lines
	No gas supply	Check that gas supply is on
	Loose wire connection	Check and repair wire connection
	Obstructed or wrong size pilot orifice	Check for obstruction or wrong size
		orifice
	Problem with alignment of pilot and	Realign pilot and igniter
	igniter
Pilot fails to remain lit	Loose wire connection	Check and repair wire connection
after igniter goes out
(Pilot may cycle on and	Air blowing pilot out	Correct air flow
off normally several times
after cold start-up before	Obstructed or wrong size pilot orifice	Check for obstruction or wrong size
the pilot heats up.)		orifice
	Problem with alignment of pilot and	Realign pilot and igniter
	flame switch
	Problem with flame switch	Check operation of flame switch
Burner does not come on	Thermostat setting too low	Adjust thermostat to a high
(burner light does not		temperature setting
come on)	Problem with thermostat sensor	Replace sensor
	Problem with temperature controller	Check or replace controller
	Problem with thermostat gas valve	Check thermostat gas valve
	Loose wire connection	Check and repair wire connection
Heat does not turn off,	Problem with thermostat gas valve	Check or replace thermostat gas
burner light is off,		valve
temperature is above
thermostat setting
Heat does not turn off,	Problem with temperature controller	Check or replace temperature
burner light is on,		controller
temperature is above
thermostat setting
Temperature varies	Low gas pressure	Check and adjust proper gas
		pressure
	Faulty thermostat sensor	Replace faulty thermostat and sensor

— 19 — F35628 (10-04)