High
9A 362 on Worcester Bosch Junior 28i

Your boiler’s internal computer chip is giving an error message because it thinks it has been fitted with the wrong component or cannot communicate with it.

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

error – incorrect HCM fitted

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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