Medium
3 flashes on Worcester Bosch Greenstar 42CDi

Your boiler is having trouble measuring the temperature of your hot water, which usually means your taps will only provide cold or lukewarm 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

Hot water NTC sensor defective.

Engineer required

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

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