High
EH 258 on Worcester Bosch Heatslave

Your boiler’s internal computer system has detected a hardware failure or a loose connection, meaning it cannot communicate with the parts that manage heat.

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 – HCM or 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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Related fault codes

202View →204View →

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