Viessmann Air Pressure Switch (Aps)

The air pressure switch enables safety protocols that check the fan is in full working order. It ensures that, if the fan fails within the boiler, there would not be a build up of toxic fumes with no means of venting them. The PCB closely monitors the air pressure switch to make sure it is completely operational before the unit is fired up, preventing the appliance from starting without one of its key safety instruments.