Monday, March 29, 2010

Expansion Tank

What's an expansion tank? Why do I need one? How can I tell if it needs to be replaced?
These are just a few of the questions you might have about expansion tanks. They serve a great purpose. They are installed at your water heater location to allow for expansion of the heated water. Most homes have a dual check valve at the meter shut-off that will not allow water to re-enter the city's water supply once it has passed by your water meter. So if there is a pressure spike or thermal expansion, the expansion tank is able to absorb the expansion. If not, the Temperature and Pressure relief valve (T&P) located on the water heater will open up and relieve the excess pressure.
If the expansion tank is leaking, it needs to be replaced. It should be replaced by a professional plumber to ensure that it is pumped up to the proper pressure. Otherwise, it will not be able to perform properly. Be sure to inspect it periodically. Check for rust and leaks. If it is full of water, it needs to be replaced. Knock on the tank and if it sounds hollow, it is still functional.
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  1. Expansion tanks are used in closed loop water heating and home heating systems, while they are not mandatory on the open systems.

  2. Expansion tank is used in closed water heating systems and domestic hot water systems to absorb excess water pressure.In some other way,it is also used in the cooling system of most internal combustion engines to allow the antifreeze.

  3. Expansion tanks are required to avoid voiding your water heater warranty. They need to be pressurized to the home's water pressure but no higher than the tank's specifications (usually 80psi).