Product Information: The air pressure switch enables safety protocols which 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 gasses with no means of venting them. The PCB closely monitors the air pressure switch to make sure it is in full working order before the unit is fired up, preventing the appliance from starting without one of its key safety features.

This part is listed against 2 boilers on our website, The Glowworm MICRON 30 FF , MICRON 50 FF .