High Lockout
0E25 on Alpha Pro Tec Plus

Your boiler's central control computer is experiencing a critical internal failure and has stopped the system from operating to prevent further damage.

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

Main PCB fault.

What causes this fault?

This fault occurs when the boiler's internal computer has suffered a critical hardware failure or a memory error. The most common reason is age-related wear on the electronic components or a sudden electrical surge that has damaged the delicate circuitry on the board.

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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