High
2 flashes green on Main Insul 7

Your boiler has detected that an external safety control, such as a heating programmer or a smart thermostat, is not communicating with or is disconnected from the unit.

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

Shutdown input: BL terminals on User Interaction Controller are open circuit

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

E125View →

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