High
46 on Alpha Intec 28GS

Your boiler has detected an interruption in a safety circuit, likely caused by an external add-on like a frost protection sensor or safety thermostat being triggered or disconnected.

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

Optional external safety sensor intervention - No continuity on external sensor circuit / external safety device has activated

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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