RWC 18 Litre AR18 Aquasystem Potable Expansion Vessel 3.5 Bar XVES050051

The RWC 18 Litre AR18 Aquasystem Potable Expansion Vessel 3.5 Bar XVES050051 is normally spherical in shape and contains a membrane or bladder. It will have a thread, normally 12.7 mm or 19.05 mm MBSP, on one end, and on the other end there will be a Schrader valve, which can be used for testing pressure or to re-instate the designated pressure required for the vessel. Potable expansion vessels are built from different materials than heating expansion vessels to ensure that the water is contaminant free and safe for human consumption. When fitted to an unvented cylinder, the internal pressure of the vessel is set to match that of the pressure reducing valve, which is determined by the set working pressure recommended by the cylinder manufacturer.