Product Information: The air pressure switch enacts safety protocols to check the fan is working correctly. It ensures that, if the fan fails within the boiler, there would not be a build up of noxious gases with no means of venting them. The PCB closely monitors the air pressure switch to make sure it is fully functional before the unit is fired up, preventing the appliance from starting without one of its key safety mechanisms.
We only have this part as fitting one appliance, The Potterton SUPRIMA 80 HE .