What does the Worcester Bosch b7 257 fault code mean?

Your boiler's main electronic brain has encountered a serious internal error and can no longer safely operate your heating or hot water.

How much does it cost to fix Worcester Bosch error code b7 257?

Typical repair cost for the Worcester Bosch b7 257 fault is £250-450 including labour.

Manufacturer manual

Control box or the HCM is defective.

Shared across the Greenstar range

This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Boiler cover options

A cover plan would handle faults like b7 257: no call-out fees, no surprise bills.

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Seeing a different code? Every code this model can display, in one place.

Almost always a stuck diverter valve on a combi.

7 signs repair isn't worth it anymore.

Break-even maths on monthly cover.