BoilerFaultCodesWorcester Bosch A1 281 Fault Code
Also written as A1281 — same fault.
The Worcester Bosch A1 281 fault code means: your boiler has detected that water is not circulating properly, likely because the system pressure is too low or there is trapped air preventing the pump from working correctly.. It appears on 5 Worcester Bosch models in our database.
Technical description: Pump stuck or running in air Little or no water in the system.
DIY fix possible
Check the pressure gauge on the front of the boiler; if it is below 1 bar, you need to top it up using the filling loop.Once the pressure is between 1 and 1.5 bar, switch the boiler off at the fused spur for 30 seconds and then turn it back on to reset.If the error persists after repressurizing, ensure all radiator valves are fully open to allow water to circulate.
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Worcester Bosch models that show the A1 281 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Worcester Bosch A1 281 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.
- Worcester Bosch Greenstar 12i System manual (PDF)
- Worcester Bosch Greenstar CDi Compact manual (PDF)
- Worcester Bosch Greenstar i manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026