Lennox Hearth L20 BF-2 TROUBLESHOOTING Qualified Technicians Only, All Models, Problem, Causes

TROUBLESHOOTING Qualified Technicians Only

(ALL MODELS)

PROBLEM		CAUSE(S)		SOLUTIONS
1) Pilot will not light, and Piezo Igniter does not	a.	Electrode wire (at Piezo Igniter) not pushed	•	Make sure connections are solid.
produce a heavy blue spark.		completely on.	•	Replace piezo igniter.
	b.	Piezo igniter is defective
2) Pilot will not light, but Piezo Igniter produces a	a. Incorrect lighting procedure.		•	Carefully follow the lighting / operating in-
heavy blue spark.	b. No gas to appliance due to shut valves or dis-			structions found in the appliance of this
		connected gas lines.	•	owner's manual.
				Check for multiple gas shut-offs; check gas
				supply lines.
3) Pilot will not stay lit.	a. Thermocouple is not firmly connected to control		•	Ensure thermocouple is fully inserted into pilot
		valve.	•	assembly.
	b. Pilot flame is not directed to top of thermocou-			Replace thermocouple.
		ple.
	c. Thermocouple is defective. Make sure connec-
		tion is solid.
4) Pilot flame stays lit, but main burner will not	a.	Burner control switch (on control panel) is in	•	Position the burner control switch to "ON"; or
light.		"OFF" position; or thermostat (if installed) is		adjust the thermostat. Refer to manufacturer's
		turned off or temperature setting is too low.	•	instructions for thermostat.
	b.	Electrical wiring is damaged or poorly con-		Refer to Control and Safety Wiring Diagram
		nected	•	(page 22) and check electrical connections.
	c.	One of the following components may be de-		Refer to Control and Safety Systems Wiring
		fective: burner control switch, thermostat, vent		Diagram (page 22). Electrically bypass com-
		spill switch, or thermopile.		ponents one at a time and replace defective
				item. See page 24 for Spill Switch trouble-
				shooting.
5) Main burner stays lit for up to 10 minutes and	a.	Flue / vent is blocked; flue gas is "spilling",	•	Examine venting system for blockage. Re-
then shuts off, pilot flame remains lit.		which activates the safety switch and shuts	•	move any blockage.
		down the appliance.		Open a window to see if the problem is cor-
	b.	(B-Vent) The house is negatively pressurized.		rected. See page 24 for Spill Switch trouble-
				shooting.
6) Smell of gas	a. Loose fittings may be allowing gas to leak out.		•	Check all joints for leakage: pilot assembly,
				gas supply system, main burner assembly, pi-
				lot and burner adjustment screws. Use a
				proper leak check solution. WARNING: Never
				use an open flame to check for leaks.
7) A thin coating of black soot forms on the win-	a.	Burner primary air inlet is restricted or	•	Be sure all openings (fresh air inlets) in stove
dow. NOTE: See page 20, Cleaning Glass.		blocked.		are free from dust and debris. Recheck these
	b. Flames make contact with logs or other sur-		•	areas periodically.
		faces.		Make sure ceramic logs are in their correct
	c.	Improper venting.	•	positions.
				Check for flue blockage, disconnected flue,
				improper installation. Make appropriate cor-
				rections.
8) A white coating forms on windows, logs, and /	a. Residues / impurities being burned off.		•	Follow cleaning guidelines outlined in the
or inside walls of firebox.				MAINTENANCE section of this manual.
9) Circulation blower makes a humming sound,	a. Impeller blades in circulation blower are dirty.		•	Disconnect electrical power to circulation
but there is no circulation air.	b. Circulation blower is defective.			blower, access blower and clean impeller
				blades as outlined in the MAINTENANCE sec-
			•	tion of this manual.
				Replace blower.

REFERENCE INFORMATION FOR QUALIFIED TECHNICIAN:

Thermopile / Thermocouple Operation

♦Thermopile: Millivolt production should be a minimum of 325 MV with pilot only.

♦Thermocouple: Millivolt product-ion should be a minimum of 14 MV with pilot only.

Drop out rate

♦TP 50-60 MV

♦TP 1 1/2-2 Min. (3 max.) if longer, replace thermopile.

PAGE 23