High Lockout
38 on Ideal Maximiser SE

Your boiler has stopped working because it has lost a secure electrical connection to the valve that controls the gas supply.

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

Check the electrical connections of the gas valve.

What causes this fault?

This fault occurs when the boiler's internal computer can no longer detect or communicate with the gas valve. The most common reason is a loose or damaged wiring connection between these two parts, or an internal electrical failure within the valve itself. Without this secure link, the boiler cannot safely control the fuel supply and must shut down.

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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