High
1021 B on Worcester Bosch 24 RSF

Your boiler is unable to track the temperature of your hot water, meaning you likely have no hot water or it is not heating up correctly.

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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Related fault codes

1022 BView →B1View →

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