High Lockout
410 on Ideal Response SE

Your boiler’s internal computer has encountered a critical error and needs a professional to reset or replace the main control board.

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 experiences a software crash or a hardware failure within its internal circuitry. It is often caused by a voltage spike in the electrical supply or simply due to components on the board wearing out over time. Because the 'brain' of the boiler can no longer safely monitor operations, it shuts the system down as a precaution.

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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