High
Blue light: On / Lockout: Off on Worcester Bosch Greenstar 15i System

Your boiler is receiving a request for heating but cannot start the sequence, even though your hot water is still working perfectly.

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

Boiler not operating during central heating demand (HW ok)

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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