BoilerFaultCodesTechnical description
Antifreeze active – fan speed variation too high – waiting during blocking function
What causes this fault?
This fault occurs when the boiler's internal computer detects that the fan is not spinning at a stable or consistent speed while trying to run a protective cycle. The most common reason is that the fan motor is beginning to fail or there is an electrical communication issue between the fan and the main control board. Because the boiler cannot guarantee the correct amount of air is moving through the system, it pauses operation as a safety precaution.
This fault is more common during the winter months when the boiler's internal anti-frost setting frequently triggers to prevent the heat exchanger from freezing.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.