High Lockout
neon4 on Glow-worm Space Saver

Your boiler is unable to light the pilot flame, which means it cannot fire up to provide heating or hot water.

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

Is there 240V~ between pilot gas valve solenoid blue and brown connections? Isolate supply, test harness continuity. If satisfactory replace printed circuit board.

What causes this fault?

This fault occurs when the boiler's control system attempts to light the pilot flame but fails to receive the electrical signal or gas flow required to start the ignition process. The most common reason is an electrical failure in the main circuit board or a faulty solenoid preventing the gas valve from opening, meaning the boiler cannot safely begin the heating process.

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

Neon 1View →Neon 2View →Neon 3View →

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