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Error code reference
Lennox Furnace Error Code E 240
Low flame current during run mode.
SourceLennox SLP98DFV - Service Manual: High-Efficiency Gas Furnacep. 19
Diagnostic procedure
The full E 240 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 micro-amperes of flame sensor using control diagnostics. Clean or replace sensor. Measure voltage of neutral to ground to ensure good unit ground. Alert clears after current heat call has been completed.
SourceLennox EL296UHE - Service Manual: High-Efficiency Gas Furnacep. 12
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
4 manuals in the MyPros+ library document this code for Lennox furnace.
Models covered by the manuals that document this code
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