5
Abnormal flame-proving signal; flame proved while gas valve is de-energized
This code typically points to
- Leaky gas valve
- Stuck-open gas valve
Next checks to confirm
- Verify no flame with gas valve de-energized
- Inspect valve leakage
Escalation
Gas valve safety fault, not just a sensor nuisance.
Reset behavior
Inducer runs until fault clears.
Safety Critical
Immediate concern