High Lockout
414 on Ideal Response SE

Your boiler’s internal computer has suffered a serious electronic malfunction and is unable to control the heating system safely.

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 failure - electronic

What causes this fault?

This fault occurs when the boiler's main control board suffers a critical hardware failure, meaning it can no longer process data or send signals to other components. It is often caused by a surge in electrical voltage, moisture getting onto the circuit board, or simply the natural degradation of the solder joints and capacitors over time.

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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