Medium
1021 on Worcester Bosch Greenstar 4000

Your boiler is struggling to detect the temperature of the water in your hot water tank, which means it may struggle to provide consistent hot water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Cylinder charging or hot water temperature sensor faulty

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

1022View →1023View →

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