Lennox Furnace Error Code E 241

E 241 means the furnace control board detected a flame signal at a point in the operating cycle when no flame should be present. This is called flame sensed out of sequence and is treated as a safety fault. The most common cause is a gas valve that is not fully shutting off. The furnace locks out to prevent a potentially unsafe condition until the issue is corrected.

The E 241 alert is designed to clear automatically once the fault condition is resolved, not simply from a manual reset. If the underlying cause, such as a leaking gas valve, has not been corrected, the error will return after reset and the furnace will shut down again. Clearing the code without fixing the root cause does not make the system safe to operate.

Repair costs depend on the component that needs to be replaced. Gas valve replacement on a Lennox furnace typically runs in the range of $200 to $600 including parts and labor, depending on the specific valve model and your location. If the issue is only a faulty flame sensor or wiring repair, costs are generally lower, often in the $75 to $200 range. A service call for diagnosis alone usually costs between $75 and $150 before any parts are factored in.

Yes, this error can indicate a gas valve that is leaking or failing to close fully, which is a condition that should be addressed promptly. The furnace shuts itself down as a protective measure when this fault is detected. You should shut off the gas supply to the furnace immediately and avoid operating the unit until the gas valve has been inspected and confirmed to be functioning correctly or replaced.

The first step of shutting off the gas and inspecting for a valve leak is straightforward, but replacing a gas valve involves working with the gas supply line and requires proper tools, knowledge, and in many areas a licensed technician. Flame sensor wiring inspection is more accessible to a knowledgeable DIYer. Any work involving the gas valve itself is strongly recommended to be performed by a qualified HVAC technician.