Hot Water Expansion Tanks

Do you ever wonder what one of these large green or blue bulbous tanks are hanging upside your heating system all about? I am going to tell you what they are.

Hi! My name is Mark Donovan from homeadditionplus.com. These are expansion tanks designed to relieve the hot water pressure in your hot water heating pipes. They are used in your portable drinking supply or your hot water supply as well as in closed hot water heating systems. And the purpose of them is to ensure a constant pressure within the pipes such that the pipes do not run the risk of becoming damaged due to excess of pressure.

The tank itself is separated by a rubber diaphragm and the upper portion is directly connected into the heating system or hot water system so it is actually filled with water. The bottom half is filled with air setting the pressure of approximately 12 PSI. When the hot water thermally expands or a valve is shut on or off on the hot water system, there is excess of pressure that builds up. When the pressure builds up, the hot water in this tank, expands a little bit down into the air carrier of the tank relieving the pressure in the piping system and maintaining a constant pressure for. This is important so that the pipes will not be damaged.

In the event the tank itself becomes damaged such as the diaphragm failing, water may completely fill this tank. When that occurs, it is defective and not operating. And the relief valve that sits on top of the tank and its purpose is to spill out some of the hot water through the pressure in the system so that again, the pipes are not damaged.

To check see whether or not the expansion tank is working properly, you can tap on it and you will hear two different sounds; a flat sound in the top portion and a hollow sound on the bottom. In addition, you can feel warmth from the top and coolness on the bottom. If for any reason, you feel heat throughout entire tank or it sounds like a sound both top and bottom, then you know you have a failed expansion tank and you should have it repaired by a plumber. So those are basic principles and purpose of an expansion tank.

If you have any other home improvement questions, visit us at homeadditionplus.com today.