High
b7 on Worcester Bosch CDi Highflow

Your boiler's computer has detected an internal communication failure, meaning it cannot safely ignite or operate your heating system.

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

Burner control 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

b1View →b2View →

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