Low
2.C on Worcester Bosch Greenstar CDi Compact

Your boiler is currently running an automated sequence to remove trapped air from the system, which typically occurs after you first turn the power on or restart the unit.

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

Air purge mode

From this model's manual
Verified against the Worcester Bosch Greenstar Cdi Compact installation & service manual.
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 because air has been detected within the boiler's internal heat exchanger or pipework, often following a period of inactivity or after the system has been drained and refilled. To protect the components from overheating, the boiler automatically enters a cycle to vent this trapped air. It is a protective measure rather than a breakdown, ensuring the water can circulate freely and safely through the appliance.

This is most common in autumn when homeowners turn their heating back on for the first time or after radiators have been bled in preparation for winter.

DIY fix possible

Wait for approximately 8 to 15 minutes for the automated cycle to complete naturally.Check that your radiator valves are open to help move air through the system.Monitor the boiler display; once the code disappears, normal operation should resume automatically.

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