22mm

A flange is a device that limits the amount of air entering a pump from the hot water cylinder. When water is heated, or replaced within the hot water cylinder, air bubbles are formed and collect around the side or the top of the cylinder. The bubbles then rise up to the top of the vent and expansion pipe. By installing a flange, these air bubbles are prevented from entering the pump, as the flange is able to draw water from deeper within the hot water cylinder. All products within Salamander Pumps’ Right Pump range require a flange, however it is best practice to install a flange on the hot water cylinder to all pumps within our Gravity Fed range to protect your pump from cavitation.