Extrol Expansion Tank

No.15, 2 gallon expansion tank

Expansion tanks are required on systems which are closed and recirculate the same fluid over and over. Solar heating systems using glycol/oil loops for freeze protection are required to have an expansion tank. The expansion tank uses an air cushion to allow for the natural expansion of liquids as temperature rises. As liquids heat up in closed loop systems, the liquid needs room to expand. Expansion tanks can be as simple as a cylindrical tank with the inlet and outlet below the lowest liquid level expected. Expansion tanks in smaller systems can have a pressurized bladder to allow for expansion. This unit has the available volume of 2 gallons. Expansion varies depending on amount and type of liquid.