Defective Thermal Expansion Tank

[DUNBAR PLUMBING]

How many years do you "think" a thermal expansion tank should last?

I give people the idea of 5-8 years tops. This is based on the factoid I've installed a pressure reducing valve to control the water pressure, spikes, extreme pressure at night time.


It's common for these tanks to go bad without the property owner never realizing it. That's why it is necessary when the opportunity strikes when the plumber is in the home to check/identify this situation and realize the dangers.

Dangers as in potable water losing its protective qualities, slowly leeching into the water system. In the majority of cases, the abundance of chlorine in the potable water system protects the end user from large amounts of exposure.

It's roughly 2 gallons on the small tank, 4 gallons on the larger tank designed to provide thermal expansion protection on water heaters 50 gallons and larger.


Thermal expansion tanks must be used on closed systems in the state of Kentucky. Closed systems are created by check valves, double check valves, any type of backflow device, pressure reducing valve, or any valve that is shut off for periods of time that does not allow water to travel back out to the main water supply.