Your boiler has paused its operation because it has detected an issue with the air flow or fan stability while trying to prevent internal freezing.

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.