High Lockout
LED 4 lit on Ideal Mexico Super 40ff - 80ff

Your boiler is receiving power correctly, but it has failed to ignite or stay lit, causing it to shut down for safety.

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

Indicates that the fuse on PCB 37 is OK.

What causes this fault?

This fault occurs when the boiler's control system attempts to start the heating process but cannot detect a stable flame. The most common reasons are a worn-out component that creates the spark, a failure in the valve that delivers gas to the burner, or a fault within the main control board that manages the ignition sequence.

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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Related fault codes

LED 2View →LED 3View →

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