BoilerFaultCodesWorcester Bosch 305 0 Fault Code
Also written as 3050 — same fault.
The Worcester Bosch 305 0 fault code means: your boiler has temporarily stopped heating water to prevent it from overheating and will automatically restart once it has cooled down.. It appears on 10 Worcester Bosch models in our database.
Technical description: Boiler in hot water anti-cycle mode
What causes the Worcester Bosch 305 0 fault?
This happens when the boiler identifies that the water temperature has risen too quickly or is too high for the current demand, triggering a brief pause to protect internal components. It is often caused by a sudden reduction in water flow, such as turning off a hot tap quickly, or by settings being adjusted to a temperature higher than the system can currently dissipate. The boiler is essentially taking a 'breather' to shed excess heat before firing up again.
This code may appear more frequently in summer when the incoming cold water mains temperature is higher, meaning the boiler reaches its target temperature much faster than in winter.
DIY fix possible
Wait up to 15 minutes for the anti-cycle timer to finishEnsure your hot water taps are fully closedCheck that the hot water temperature setting on the boiler display is not set unnecessarily high
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Gas Safe Register →Worcester Bosch models that show the 305 0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch 305 0 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026