High
F20 on Saunier Duval Thema F 30 E Plus

Your boiler's control panel and its internal brain are not talking to each other correctly, which means the system cannot safely operate.

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

User interface incompatible with Main PCB

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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