High
9.3 on Worcester Bosch Greenstar 25i (ZWB 7-25)

Your boiler's main computer control panel is failing to process instructions correctly, which has caused it to stop working for safety reasons.

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

GFA-Asic-error (00h - FFh)

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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