Medium
Ad on Worcester Bosch ZB 7 27 HE

Your boiler has lost its connection to the sensor that measures how hot your stored hot water is, so it may stop heating your hot water cylinder.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

What the manual says

Manufacturer manual

Loose or broken contact on heat store NTC sensor

From this model's manual
Verified against the Worcester Bosch Greenstar 25i Zwb 7 25 installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

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

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