High
F12 on Saunier Duval Thema F 30 E Plus

Your boiler's electronic control panel and internal circuit board are struggling to talk to each other, preventing the boiler from starting.

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/Main PCB communication fault

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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Related fault codes

F11View →F13View →

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