High
E 37 on Keston C40

Your boiler's temperature-sensing system has lost its connection, preventing the unit from accurately reading the water temperature and safely managing your heating.

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

Return thermistor open circuit - check/replace connections/thermistor

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

E 36View →

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