High
F0 242 on Worcester Bosch Junior 24i

Your boiler’s internal computer has developed a fault and can no longer communicate with the main control system, preventing the boiler from heating.

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

Control box or the heat control module (HCM) is defective – the HCM and control box connections need to be checked

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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