High
360 on Worcester Bosch 26 CDi Xtra

Your boiler's computer brains are having a communication problem because an incorrect or faulty internal component has been detected.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

What the manual says

Manufacturer manual

Heat control module (HCM) invalid – the inserted HCM does not correspond with the control box

From this model's manual
Verified against the Worcester Bosch 26 Cdi Xtra 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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