High
235 on Worcester Bosch Greenstar 12i System

Your boiler's computer components are not talking to each other correctly because one part is running outdated software, preventing the system from starting.

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

Incompatible HCM software version Revised HCM software requires latest version of control box to operate correctly

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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