High
208 on Worcester Bosch Greenstar CDi Compact

Your boiler is currently locked in a testing mode used by engineers to check the flue system, which prevents it from heating your home normally.

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

Test mode active due chimney switch

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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