Diaphragms

Also known as a membrane, it is a boiler part that is normally located within the diverter valve or hydraulic section of the combination boiler. Its main purpose is to move a pin that then operates a microswitch which in turn sends a signal to the printed circuit board. The signal is normally to indicate the pump is running or there is a demand for hot water. They are sometimes also referred to as the pump proving – flow diaphragm or the domestic hot water DHW diaphragm, having this feature is what makes a combi boiler so popular due to the fact the boiler can provide hot water and heating without the need for a cylinder.