BoilerFaultCodesTechnical description
Frost protection system has been activated
What causes this fault?
This code appears when the boiler's internal temperature sensors detect that the water inside the unit has dropped to a level where it is at risk of freezing. To protect the heat exchanger and pipes from expanding ice damage, the boiler automatically fires up the burner to warm the water back to a safe temperature. Once the system reaches a secure temperature, the code will clear and the boiler will return to normal operation.
This display is almost exclusively seen during the winter months or during sudden overnight cold snaps when temperatures drop near freezing.
DIY fix possible
Check that your gas and electricity supplies are still activeEnsure any exposed external pipework (condensate pipe) is insulated or not frozenMonitor the boiler; the code should disappear once the water temperature inside the unit rises sufficiently