Lennox Hearth LBV-4324EN-H, LBV-3824EN Troubleshooting The Electronic Ignition System, Symptom

TROUBLESHOOTING THE ELECTRONIC IGNITION SYSTEM

Note: Before troubleshooting, be sure that the appliance main line gas shut-off valve, the gas control valve and the wall switch are in the “ON” position.

Important: Valve system troubleshooting should only be accomplished by a qualified service technician.

	SYMPTOM	POSSIBLE CAUSES	CORRECTIVE ACTION
1.	Burner will not light.	A. Damper closed or	Ensure damper control lever is locked in the open position, all the way to the
		Damper Switch defective.	right. If the damper control lever is locked in the open position troubleshoot
			through Steps B., C. and D. below. If the main burner will still not light,
			determine if the damper switch is defective and replace if necessary.
		B. Faulty Valve System.	See Below.
		C. Faulty limit switch.	Reset the limit switch button. If still not working, access the leads attached to
			the limit switch and check for continuity. If no continuity, replace limit switch.
		D. “OFF/ON” or wall switch	Disconnect the two black wires from the wire nuts. Test switch(s) for
		defective.	continuity with a multimeter. If continuity is not indicated, switch(s) is
			defective and must be replaced.
			Note: Before replacing “OFF/ON” switch, be sure to check wiring for loose
			connections or broken wires and repair as needed.
2.	Burners come “ON” but	A. Burner orifice plugged.	Check main burner orifice(s) for stoppage. Clean or replace.
	go “OFF.”
		B. Obstructed vent system.	Check vent system for obstructions.

START

•Turn Off Gas Supply

•Assure Valve Switch Is In ON Position

•Disconnect Control Harness

•Set Thermostat To Call For Heat

Insert A	End View Of
	Control Harness
24 Volt Hot	Connector
	24 Volt
	Common

•Check For Proper Voltage At Control Harness (See Insert A). Voltage Should Be 24V Between Thermostat Or Pressure Switch

And 24V Common And 24V Hot. 2

YES

• Plug Control Harness Into Valve. Wait For
Internal Check Delay.
• Igniter Warms Up And Glows Red.
1	YES

	CHECK
NO	• Line Voltage Power
	• Low Voltage Transformer
	• Limit Controller
	• Thermostat
	• Wiring

NO	• With Pilot Burner Cable Connected, Measure
	Voltage At Valve HSI Element Output. 24V
	Nominal. (See Insert B)	2
	1

YES

NO

• Replace Valve.

24 Volt

Switched

Check For Damaged Or Missing Terminals In Connector

Insert B

Igniter Terminals

• Turn On Gas Supply. • Pilot Burner Lights.

YES

•Replace Igniter/Flame Rod Assembly.

YES

NO	• Check That Pilot Gas Is Flowing. Wait To		NO	• Replace Valve.
	Assure Plot Gas Tubing Is Purged. Recycle
	Call For Heat If Necessary.
		YES

•Measure Voltage Between 24V Hot And 24V Common

Leads To Valve Control. Must Measure At Least 19.5		NO	• Check Transformer And
VAC With Igniter Powered (See Insert A). To Identify
			Line Volt Supply.
Proper Lead, This Check Must Be Done With The
Valve Control Connected And Igniter Powered.
	YES

•Replace Pilot Assembly.

			• Check That Pilot Flame Makes Good Contact With
		NO	Pilot Burner Flame Rod.
• Main Valve Opens And Main Burner Lights.			• Check For Good Electrical Connection Through The
			Pilot Tubing.
			• If Both Of The Above Are Good, Replace Igniter/Flame
	YES		Rod Assembly.
					YES
• System Is Okay.				• Cycle Thermostat Off And Back On.

1	Igniter Will Cycle Off And Back On Once During	2	When Measured Voltage At Connections, Use	• Main Burner Lights.	NO		• Replace Valve.
	The 90 Second Ignition Trial. All Voltage		Care To Assure Terminals Are Not Damaged.
	Measurements Must Be Taken While The Igniter
	Is Powered.					15