Lennox Hearth 875022M Indoor Fireplace User Manual


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31
TROUBLESHOOTING THE ELECTRONIC IGNITION SYSTEM
SYMPTOM POSSIBLE CAUSES CORRECTIVE ACTION
See Below.
Disconnect the two black wires from the wire nuts. Test switch(s) for continu-
ity 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.
Check main burner orifice(s) for stoppage. Clean or replace.
Check vent system for obstructions.
A. Faulty Valve System.
B. “OFF/ON” or wall switch
defective.
A. Burner orifice plugged.
B. Obstructed vent system.
1. Burner will not light.
2. Burners come “ON” but
go “OFF.”
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.
•Turn Off Gas Supply
•AssureValve Switch Is In ON Position
•DisconnectControlHarness
•SetThermostatTo Call For Heat
•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.
•LineVoltage Power
•LowVoltage Transformer
•LimitController
•Thermostat
•Wiring
2
CHECK
START
NO
•PlugControlHarnessIntoValve. Wait For
Internal Check Delay.
YES
•IgniterWarms Up And Glows Red.
•WithPilotBurnerCableConnected,Measure
Voltage At Valve HSI Element Output. 24V
Nominal. (See Insert B)
NO
•ReplaceIgniter/FlameRodAssembly.
YES
•ReplaceValve.
NO
•Turn On Gas Supply.•PilotBurnerLights.
•CheckThatPilotGasIsFlowing.Wait To
Assure Plot Gas Tubing Is Purged. Recycle
Call For Heat If Necessary.
NO
YES
NO
YES
YES
1
•MeasureVoltage Between 24V Hot And 24V Common
Leads To Valve Control. Must Measure At Least 19.5
VAC With Igniter Powered (See Insert A). To Identify
Proper Lead, This Check Must Be Done With The
Valve Control Connected And Igniter Powered.
•CheckTransformer And
Line Volt Supply.
NO
•ReplacePilotAssembly.
YES
•CheckThatPilotFlameMakesGoodContactWith
Pilot Burner Flame Rod.
•CheckForGoodElectricalConnectionThroughThe
Pilot Tubing.
•IfBothOfTheAboveAreGood,ReplaceIgniter/Flame
Rod Assembly.
•CycleThermostatOffAndBackOn.
YES
•MainValve Opens And Main Burner Lights.
NO
YES
•SystemIsOkay.
YES
•MainBurnerLights.
NO
2
1
Igniter Will Cycle Off And Back On Once During
The 90 Second Ignition Trial. All Voltage
Measurements Must Be Taken While The Igniter
Is Powered.
When Measured Voltage At Connections, Use
Care To Assure Terminals Are Not Damaged.
•ReplaceValve.
•ReplaceValve.
24 Volt Hot
End View Of
Control Harness
Connector
24 Volt
Common
24 Volt
Switched
Check For Damaged Or Missing Terminals
In Connector
Insert A
Igniter Terminals
Insert B
2
1
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