BoilerFaultCodesTechnical description
Fan unit waiting period
What causes this fault?
This fault occurs when the boiler's internal computer detects that the fan isn't spinning at the correct speed required to safely clear exhaust gases before ignition. The most common reasons are a buildup of dust or debris within the fan assembly, or a communication error between the fan and the main control board. If the fan cannot reach its target speed, the boiler will temporarily pause as a safety precaution.
This issue can occasionally surface during very windy weather, as extreme gusts can create back-pressure in the flue that interferes with the fan's startup speed.
DIY fix possible
Wait for the boiler to complete its automatic retry attempt.Restart the boiler by turning the power off and back on at the fused spur.Check that the flue terminal outside is not obstructed by debris or plants.Contact a Gas Safe engineer if the code persists or appears frequently.