Expansion Tanks

Expansion tanks may be required as part of your system because of thermal expansion. When water is heated, it expands, when cooled, it contracts. As that water is heated, the pressure may go from 60 psi to as high as 150 psi. Any pressure over 80 psi is considered to be excessive and can cause damage to piping, fixtures and any appliances connected to the water system. Expansion tanks have rubber bladders inside and since air can be compressed, the rubber bladder inside the tank is filled with air. As the water gets heated it increases its volume and displaces into the thermal expansion tank. When the water pressure is relieved (i.e. through a faucet being opened) the air bladder pushes the water back out of the expansion tank, making it ready for another cycle. This greatly reduces the stress on the entire water system and everything connected to it.