Low
H03 on Worcester Bosch Greenstar 12i System

Your boiler is simply reminding you that it is time for its annual safety service to keep it running efficiently and safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

The number of operating hours set for service interval has expired.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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