Lennox Hearth VIN Troubleshooting, Symptom, Corrective Action, Probable Cause, tors

TROUBLESHOOTING

NOTE: When troubleshooting the gas control system, be sure the external gas shut off valve, located at the gas supply inlet is in the “ON” position.

IMPORTANT: Call your gas supplier or plumber for additional help with any gas control problem. Valve system troubleshooting should only be accomplished by a qualified service technician.

SYMPTOM	PROBABLE CAUSE	CORRECTIVE ACTION
Thin black coating	Improper log or ember	See Log Set and Ember Installation.
(soot) forms on the	placement.
viewing glass, logs, or		Check for obstructions in vent pipe, check for proper restrictor setting. See Flue Restric-
firebox.	Blocked flue.
		tors.
	Improper air shutter	See Air Shutter Adjustment.
	setting.
Humming or whistling	Normal operating noise.	See Quiet Operation. The noise may be reduced by slightly turning the flame down. Turning
coming from fireplace.		the flame down will reduce the heat output of the fireplace.
	Dirt in burner orifice.	Clean orifice.
A change in flame	A change in gas pres-	Have your gas supplier check for correct gas pressure (7” W.C. natural gas; 11” W.C. LP
appearance or burner	sure.	gas).
operation.		See Log Set and Ember Installation.
	Improper ember or log
	placement.
Pilot will not light.	No gas supplied to unit.	Turn on gas.
	Air in line.	To purge, hold in control knob in pilot position for 1-2 minutes and light.
	Defective igniter (no	Check for spark at electrode and pilot, if no spark and electrode wire is properly connected,
	spark at electrode).	replace igniter.
	The valve control knob	See Lighting Instructions.
	is not turned to “pilot”
	and pushed in.
Pilot will not stay lit	Pilot flame is not sur-	Check pilot flame adjustment (see Maintenance and Servicing section).
after carefully following	rounding thermocouple.
lighting instructions.	Thermocouple not	Check the connection between the thermocouple lead and the valve. Turn control knob to
	generating sufficient	“pilot” and push in and light pilot. While lit, take millivolt reading at lead going into valve’s
	voltage.	CPU. Minimum reading should be 17 millivolts. If less, replace thermocouple.
	Air in gas supply line.	Purge air in pilot gas line by holding in control knob at “pilot” and sparking igniter. The air
		in the line may take up to several minutes to purge.
Main burner will not	Pilot has gone out.	See Lighting Instructions.
burn.	Rocker switch or	Disconnect rocker switch and thermostat wires at terminals 1 and 3 on valve. Jumper
	thermostat wires are	across from 1 to 3 with pilot lit. If burner comes on either rocker switch or thermostat wir-
	defective.	ing is not functioning.
	Thermopile may not be	Make sure thermopile is fully engulfed by the pilot flame. Check thermopile with millivolt
		meter. With pilot lit and the rocker switch and thermostat off, the millivolt reading with the
	generating sufficient	meter connected to valve terminals 1 and 2 should be after 2 minutes at least 325. If the
	millivolts.	thermopile lead connections are good at terminals 1 and 2 and readings are less than 325,
		replace faulty thermopile.

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