High
neon '12' illuminated on Ideal Classic NF

Your boiler has detected that a vital internal temperature sensor is disconnected or has failed, preventing it from heating your home safely.

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

Sensor (NTC) removed from P.C.B. and thermostat neon '12' is illuminated.

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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