High
E35 on Johnson Starley Comet 80

Your boiler's temperature sensor is reporting an error, meaning the system can't accurately measure how hot the water is as it leaves 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

Flow thermistor 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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