Water Expansion Tank Air Pressure

Size the tank so that the pressure at the system s pressure relief valve is 5 psi below that valves rated opening.

Water expansion tank air pressure. In some tanks there is no barrier between the air and water which means the tank must be charged periodically. Pressurizing the air side of the tank to equal the static pressure of the water at the expansion tank location and. The red cap atop the expansion tank shown at left covers the air valve through which the expansion tank s air pressure is pre set at the factory. Use a bicycle pump or compressor to fill the tank to match the system pressure you noted earlier.

It is important to check it every so often to ensure the system is functioning proper. Most of the time your tank is half water and half air. If the pressure is less than 12 psi you will need to add some air s. The water heater expansion tank serves as an overflow receptacle by absorbing excess water volume that occurs when water is heated as well as absorbing fluctuations in the incoming water supply pressure.

Start by removing the protective cover from the air valve on the tank. Shut off the cold water valve that feeds your water heater it should be just upstream of your expansion tank. Typical factory air pre charge settings is 12 psi the same as the automatic water feed valve boiler set pressure when the boiler is cold. Since water expands when it is heated due to thermal expansion the water heater creates extra water volume every time it heats water.

Check your manual for the precise rating for your expansion tank. Most expansion tanks come pressurized to 12 40 psi but before you install the tank you have to match the system pressure. Turn on a hot water fixture that s closest to your. According to well x trol bladder type well tank air precharge.

Water is incompressible so the tank must contain some air. Well x trol water pressure tanks are shipped from the factory with a standard precharge of 18 psig for models wx 101 and wx 102. If you are on a private water system you probably have a pressure tank. Use a tire gauge to check the pressure.

The key concepts are. It is used to absorb excess water pressure. Some models may come with different pressure settings however. When water is heated or a hot water faucet is turned off abruptly pressure builds from expanding water molecules.

Read the pressure setting. From there the water passes into the pressure tank which is a second holding tank connected to a jet pump that keeps the water pressurized. Most expansion tanks require a psi reading of about 12 psi. When pressure increases the diaphragm is pushed upward.