Watts 0066608 15-Gallon Non-Potable Water Expansion Tank 3/4" MNPT ETX-90

The Watts 0066608 15 Gallon Expansion Tank, model ETX-90, is an essential part in closed loop hydronic cooling and heating system that is meant to provide space for the water to expand and contract as it is heated or cooled. This 15 GTANK has a 3/4” MHNPT inlet connection to deal with the additional amount of water that is produced when it is heated. This part is designed for such expanded water, so the system doesn’t get over-pressurized and run with safe pressure limits only. Internally, the tank normally has a flexible partition or bladder that separates the system water from an initial charge of air.