Worcester Bosch part is located within the air pressure switch section. The air pressure switch is a safety device which checks the fan is in full working order. It ensures that if the fan fails, there would not be a build up of toxic gasses 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 features.

Brand Name	Worcester Bosch