High
323 / A8 on Worcester Bosch Greenstar CDi Compact

Your boiler's internal control computer has lost its connection, preventing it from processing commands and operating your heating or hot water correctly.

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

EMS communication error

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

A8View →

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