High
Lockout lamp (red) on on Biasi Gaia

Your boiler is trying to light but cannot successfully create or detect a flame, 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

The boiler starts the ignition cycle and remains in lockout. Possible causes: no gas, ignition/flame detection electrode failure, or gas valve failure.

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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