High
F20 on Saunier Duval Semia Condens F30 E

Your boiler's computer components are not communicating correctly, meaning the system cannot run because it does not recognize its own internal hardware configuration.

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

Software incompatibility. Incorrect user interface or main board. Incorrect product code

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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