High
1021 B on Worcester Bosch Heatslave

Your boiler is unable to tell how hot your water is because a internal sensor is either unplugged or has failed, meaning you likely have no hot water.

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

Hot water temperature sensor is defective – the plug to the hot water temperature sensor may not be connected

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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