0-A1 Low

Worcester Bosch 0-A1 Fault Code

Also written as 0A1 — same fault.

The Worcester Bosch 0-A1 fault code means: your boiler has been manually switched off or into a service mode and simply needs to be restarted or reset to resume normal operation.. It appears on 1 Worcester Bosch model in our database.

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: Manual operation: OFF/ON.
Typical repair cost £0-80 (including labour)

DIY fix possible

Locate the main Power/Reset button on the boiler control panel.Press and hold the Reset button for 3 to 5 seconds.Wait for the boiler to complete its startup sequence and return to the home screen.

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Worcester Bosch models that show the 0-A1 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Worcester Bosch 0-A1 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