BoilerFaultCodesWhat the manual says
Manufacturer manualAppliance is in Air purge mode, see service function 2.C.
What causes this fault?
This occurs when air becomes trapped within the boiler's heat exchanger or pump, often following a recent repair or system refill. The boiler automatically detects this air and triggers a programmed sequence to pulse the pump and vent the bubbles safely to ensure efficient operation. It isn't a mechanical failure, but rather a protective routine to prevent the system from overheating.
This code is more common in autumn when homeowners first switch their heating back on or bleed their radiators after a long period of disuse.
DIY fix possible
Wait for the timer to count down; the process usually takes 2 to 10 minutes.Ensure your radiator valves are open to help move air through the system.Check the pressure gauge is between 1 and 1.5 bar; top up if it has dropped.
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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Related fault codes
All 365 fault codes on the Greenstar CDi Compact
Seeing a different code? Every code this model can display, in one place.