Product Information: The air pressure switch acts as a safety mechanism which ensures 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 noxious gases with no means of venting them. The PCB closely monitors the air pressure switch to make sure it is fully operational before the unit is fired up, preventing the appliance from starting without one of its key safety features.
This part is present in 10 different boilers in the Saunier Duval range including the Saunier Duval THEMAPLUS F 23 E , THELIA 623 NC , THELIA 623 , THELIA 23 E NC , THELIA 23 .