Technical description
Water circulation volume self-test. The self-test for the water circulation volume is activated.
What causes this fault?
This status code appears when the boiler is performing a routine check to ensure the internal pump is moving water through the heat exchanger correctly. It is a protective measure to ensure the system doesn't overheat before the burner fires up fully. This is usually part of the boiler's normal start-up cycle rather than a component failure.
DIY fix possible
Wait for 5 to 10 minutes as this is often a temporary status code and not a permanent fault.Check that your radiator valves are open to allow water to circulate properly.Ensure the boiler pressure is in the green zone, typically between 1.0 and 1.5 bar.