Troubleshooting Guide - Electronic - Lennox EDV4540CPM Care And Operation Instructions Manual

TROUBLESHOOTING THE ELECTRONIC IGNITION SYSTEM
ote: Before troubleshooting, be sure that the appliance main line gas shut-off valve, the gas control valve and the wall switch are in
N
the "ON" position.
Important: Valve system troubleshooting should only be accomplished by a qualified service technician.
SYMPTOM
1. Burner will not light.
2. Burners come "ON" but
go "OFF."
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
Connector
24 Volt Hot
24 Volt
Common
24 Volt
Switched
Check For Damaged Or Missing Terminals
In Connector
Insert B
Igniter Terminals
Igniter Will Cycle Off And Back On Once During
1
The 90 Second Ignition Trial. All Voltage
Measurements Must Be Taken While The Igniter
Is Powered.
Order Parts at: PartsFor.com or 866-607-2787
POSSIBLE CAUSES
A. Faulty Valve System.
B. "OFF/ON" or wall switch
defective.
A. Burner orifice plugged.
B. Obstructed vent system.
• 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.
YES
• Plug Control Harness Into Valve. Wait For
Internal Check Delay.
• Igniter Warms Up And Glows Red.
1 YES
• Turn On Gas Supply. • Pilot Burner Lights.
YES
• Main Valve Opens And Main Burner Lights.
YES
• System Is Okay.
When Measured Voltage At Connections, Use
2
Care To Assure Terminals Are Not Damaged.
Order Parts at: PartsFor.com or 866-607-2787
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.
CHECK
• Line Voltage Power
NO
• Low Voltage Transformer
• Limit Controller
• Thermostat
2
• Wiring
• With Pilot Burner Cable Connected, Measure
NO
Voltage At Valve HSI Element Output. 24V
Nominal. (See Insert B)
YES
• Replace Igniter/Flame Rod Assembly.
YES
NO
• Check That Pilot Gas Is Flowing. Wait To
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
VAC With Igniter Powered (See Insert A). To Identify
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
Pilot Burner Flame Rod.
NO
• Check For Good Electrical Connection Through The
Pilot Tubing.
• If Both Of The Above Are Good, Replace Igniter/Flame
Rod Assembly.
YES
• Cycle Thermostat Off And Back On.
• Main Burner Lights.
NO
• Replace Valve.
1 2
NO
• Replace Valve.
NO
• Check Transformer And
Line Volt Supply.
NO
• Replace Valve.
27