Medium
A5 on Worcester Bosch CDi Highflow

Your boiler is having difficulty reading the temperature of the water stored in its internal tank, which may cause your hot water to fluctuate or fail to heat up properly.

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

Tank NTC defect

Engineer required

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

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Related fault codes

A7View →

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