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Error code reference
Lennox Furnace Error Code 1+3
Flame sensed out of sequence: flame still present. Flame sensed without gas valve energized.
SourceLennox SL280UHV(X) Furnace - Service Manualp. 9
Diagnostic procedure
The full 1+3 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check supply voltage; control will not respond to heating call until voltage rises above 75 volts.
SourceLennox EL180DFE - Service Manual: Mid-Efficiency Gas Furnacep. 8
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
9 manuals in the MyPros+ library document this code for Lennox furnace.
Models covered by the manuals that document this code
- C33-18A-2F
- C33-24A-2F
- C33-30A-2F
- C33-36A-2F
- EL180DF045E36A
- EL180DF070E36B
- EL180DF090E48B
- EL180DF110E60C
- EL180DFE
- EL180UH045E36A
- EL180UH045XE36A
- EL180UH070E36B
- EL180UH070XE36B
- EL180UH090E60C
- EL180UH110E60C
- EL180UH110XE60C
- EL180UHE(X)
- EL280UH070P24A
- EL280UH070P36A
- EL280UH070XP36A
- EL280UH090P36B
- G60UH-1
- G60UH-24A-045
- G60UH-24A-045X
More models are covered than are listed here.
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