Lennox EL296UHV Error Code E 241: Flame Sensed Out of Sequence

What Does Code E 241 Mean?

Error code E241 on the Lennox EL296UHV means flame was sensed out of sequence — the flame sensor is reading current at a time when no gas should be flowing and no flame should exist. The SureLight control treats this as a serious safety condition and responds by trying to stop gas flow and flagging the fault, because a flame present out of sequence can mean fuel is reaching the burners when it should not be.

The most concerning cause is a gas valve that leaks past its seat when it is supposed to be closed, allowing gas to reach the burner area and ignite from residual heat, which the flame sensor then detects. Other possibilities include a flame sensor generating a false signal or electrical interference on the flame-sense circuit that the board misreads as flame. Because a leaking gas valve is a genuine hazard, this code must be treated as a possible gas problem until a technician proves otherwise.

E241 is the immediate flame-out-of-sequence fault; when the condition repeats, the board escalates to E275, a soft lockout for flame out of sequence that forces a timed safety wait. It is distinct from E204 (gas valve mis-wired), which is a wiring fault rather than a leak. The alert clears when the fault condition is recovered, but the underlying gas-valve question still needs professional inspection.

What You'll Notice

• The seven-segment display shows E241
• The burners appear to stay lit, or briefly relight, after the heating cycle should have ended
• You see flame through the sight glass when the furnace should be off
• The furnace shuts itself down and may refuse to run a normal cycle
• A gas odor near the furnace (treat this as an emergency — see the guidance below)

Common Causes

How This Is Diagnosed

Because E241 can signal a leaking gas valve, a technician shuts off the gas supply and then checks whether flame or gas is present when the valve is commanded closed. They inspect the gas valve for leak-by past its seat and verify it seals fully, and they confirm the flame sensor and its wiring are not producing a false out-of-sequence signal or picking up electrical interference.

They also check that the valve is correctly wired, since a mis-wired valve is tracked separately as E204, and confirm the control is reading the flame circuit accurately. If the valve is leaking, it is replaced. This is diagnostic information only; shutting off gas and inspecting or replacing the gas valve are technician tasks and must never be attempted as a DIY repair.

When to Call a Professional

This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:

• The display shows E241 — treat it as a possible gas-valve leak and stop using the furnace
• The burners stay lit or relight after the cycle should have ended
• You can see flame through the sight glass when the furnace should be off
• E275 (flame-out-of-sequence soft lockout) appears along with E241
• You smell gas at any time — leave the house immediately and call your gas company before anything else

✓ Verified against manufacturer service manual — March 2026