The Worcester Bosch air pressure switch is a safety instrument which ensures the fan is fully operational. It ensures that, if the fan fails within the boiler, there will not be a build up of toxic fumes with no means of venting them. The printed circuit board 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 instruments.

Brand Name	Worcester Bosch