Lennox · Furnace / HVAC
E241 Flame sensed out of sequence
What this code means
The board is detecting a flame signal at a point in the cycle when it shouldn't be present — a safety-critical fault.
Most likely causes
- Faulty gas valve
- Cracked flame sensor giving a false reading
- Control board relay failure
What to try first
Do not attempt to bypass this fault. Shut off gas to the unit and have it inspected before further use.
Safety first: stop using the appliance and shut off its gas or power until it has been inspected — this fault category is associated with fire or gas risk.
FAQ
What does Lennox error code E241 mean?
Flame sensed out of sequence. The board is detecting a flame signal at a point in the cycle when it shouldn't be present — a safety-critical fault.
Can I fix Lennox code E241 myself?
No — stop using the appliance and shut off its gas or power until it has been inspected. This fault category is associated with fire or gas risk.
What causes Lennox code E241?
The most common causes are: faulty gas valve; cracked flame sensor giving a false reading; control board relay failure.
Other Lennox furnace codes
All Lennox furnace error codes →
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This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.