High
RETURN THERMISTOR FAULT on Johnson Starley J32 System ET

Your boiler has detected an issue with the sensor that monitors the temperature of the water returning to the unit, causing it to shut down to prevent damage.

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

Check the resistance using a suitable multi-meter connected across the thermistor’s terminal pins

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

FLOW THERMISTOR FAULTView →

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