Low
305 on Worcester Bosch Greenstar 8000 Life Combi

Your boiler is temporarily pausing the hot water production to prevent itself from overheating or cycling on and off too frequently.

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.

What the manual says

Manufacturer manual

Boiler in hot water anti-cycle mode

From this model's manual
Verified against the Worcester Bosch Greenstar 8000 Life Style installation & service manual, page 77.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This code appears when the boiler has reached its maximum internal temperature for hot water and needs to briefly shut down the burner to cool down. It is often caused by a lack of water flow through the heat exchanger, or because the taps have been turned on and off very quickly several times. By entering this mode, the boiler is simply protecting its internal components from excessive heat and wear.

This can be slightly more common in summer, as the incoming mains water is naturally warmer and the boiler reaches its target temperature much faster than in the winter.

DIY fix possible

Wait up to 15 minutes for the anti-cycle timer to expireEnsure hot water taps are fully closedCheck that the hot water temperature setting on the control panel is not set excessively high

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