High Lockout
Flame on before gas valve on on Ideal Logic Max Heat

Your boiler has detected a flame when there shouldn't be one, which means the internal sensors or ignition parts are sending incorrect signals to the control board.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Internal boiler wiring integrity or electrode deterioration.

What causes this fault?

This fault occurs when the boiler's control system detects an electrical current that mimics a flame, even though the gas hasn't been turned on yet. The most common reason is a buildup of carbon or moisture on the ignition electrode, which causes it to send a false 'fire' signal to the main computer. In some cases, it can also be caused by a fault within the internal wiring or the control board itself misreading the sensor data.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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