High
360 on Worcester Bosch Junior 24i

Your boiler's internal computer brain is reporting a compatibility error, meaning it doesn't recognize the plug-in electronic chip that controls its heating functions.

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.

Technical description

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

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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Related fault codes

200View →203View →

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