High Lockout
42 on Remeha Quinta 30

Your boiler's internal computer brain has experienced a critical error and can no longer 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

Control box failure

What causes this fault?

This fault occurs when the boiler's internal computer experiences a catastrophic electronic failure, preventing it from processing safety information or managing the burner. The most common reason is the natural degradation of electrical components on the circuit board, which can sometimes be accelerated by power surges or moisture ingress. Because the brain of the boiler is no longer functioning correctly, it shuts down the system entirely to ensure your home remains safe.

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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