BoilerFaultCodesTechnical description
Winter anti-freeze protection in operation
What causes this fault?
This code appears when the boiler's internal sensor detects that the water temperature has dropped below a safe threshold, typically around 8°C. To protect itself from frost damage, the boiler automatically fires the burner or runs the pump to circulate warm water until the temperature rises. This is a normal safety feature rather than a breakdown of any specific part.
This status code is most common during the winter months when outdoor temperatures drop low enough to affect the water held within the boiler casing.
DIY fix possible
No action is required as this is a normal safety function.Ensure the condensate pipe outside is not frozen or blocked.Check that your oil supply is sufficient to allow the boiler to run its cycle.