Residential Expansion Tank Pressure

This is usually between 40 and 60 psi.

Residential expansion tank pressure.

If the pressure setting reads less than 12 psi it probably will since you drained water from the tank attach an air compressor or hand air pump to the air fitting connection and pump air into the expansion tank. Read the pressure requirement on the side of the tank. Most expansion tanks are set to a pre charge of 20 psi when they leave the factory while the majority of residential water systems have significantly higher water pressure than that. Use an air gauge to check the pressure inside the tank.

Twelve psi is appropriate for systems where the top of the piping is about 16 feet above the inlet of the expansion tank assuming that 5 psi static pressure is desired at the very top of the system to allow air vents to function properly. The installer may check the air charge using an accurate gauge type pressure gauge and as we explain in this article series for taller buildings requiring a higher cold starting pressure in the boiler the expansion tank may need to be pre charged to that same pressure level a setting above 12 psi in which case your heating service technician may add a bit of air to the pressure tank through its normally sealed air valve. Use a bicycle pump or compressor to fill the tank to match the system pressure you noted earlier. Bleed air pressure out of the water tank or add air pressure into the water tank until the tank pressure is at the desired set pressure.

The air pressure should be 12 psi pounds per square inch. Most expansion tanks come pressurized to 12 40 psi but before you install the tank you have to match the system pressure. Find pressure tanks at lowe s today. Use a tire gauge to check the pressure.

Obtain a suitable thermal expansion tank based on the size of your water heater. If your pump has a pressure gauge add air until the pressure is 12 psi. Start by removing the protective cover from the air valve on the tank. For example if your well pump pressure control switch is set to cut in start pumping water from the well at 30 psi then set the pressure tank to 30 2 28 psi.

You should also have a mechanism in place to check the pressure such as a water pressure gauge that can tell you if the tank is functioning properly or if the diaphragm has been damaged.