BoilerFaultCodesWorcester Bosch G2 Fault Code
The Worcester Bosch G2 fault code means: your boiler has detected an issue with the cold water arriving at the unit, meaning it cannot safely heat water for your taps or shower.. It appears on 1 Worcester Bosch model in our database.
Technical description: Cold water fault inlet pipe
What causes the Worcester Bosch G2 fault?
This fault occurs when the boiler cannot detect a consistent flow or pressure of cold water entering the system. The most common reason is a blockage caused by grit or debris in the inlet filter, or a mechanical failure of the internal turbine that monitors water movement.
DIY fix possible
Check that the main water stopcock in your home is fully open.Ensure any isolation valves on the pipework leading to the boiler are turned to the 'on' position.Check with your local water provider to see if there is a supply outage or burst pipe in your area.
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Gas Safe Register →Worcester Bosch models that show the G2 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch G2 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