Are pressure relief tanks on the cold water inlet line of a gas hot water heater necessary? How do they work?

Hi Tony

Are you asking if EXPANSION tanks are necessary? If you are asking about expansion tanks then the answer is yes, but only if you have a closed water system such as one that has a check valve, a backflow preventer or a pressure reducing valve. Otherwise, expansion tanks are not usually needed on a water heater as thermal expansion is handled by the water expanding back into the water system of the city/town/well, etc.

You can read more at this link:

Thermal Expansion - Learn About - Watts

Scroll down the page for the article on expansion tanks.

Mark