How much pressure should be in a boiler expansion tank?

Expansion tanks are pre-charged with a 40 PSI air charge. If the inlet water pressure is higher than 40 PSI,the expansion tank’s air pressure must be adjusted to match that pressure but must not be higher than 80 PSI.

What happens if expansion tank pressure is too high?





If the pressure is too high, it can wreck even a new expansion tank. Too low of psi, and the bladder will never “squish” to take up expansion. The psi on the in line psi after the PRV, and the precharge on the expansion tank should be the same.

Should you drain expansion tank?

Draining the expansion tank should be done periodically, usually once or twice a year. We recommend doing this maintenance before the cool season so you don’t have to work with hot water and risk getting burned. Turn off the boiler and close the water supply valve.

Why does my expansion tank keep failing?

This can occur as a result of mineral deposits or other debris. Some older expansion tanks lack the internal bladders used in newer models. This component is what separates the water and air pressure. As a result, air can escape the tank and enter your system’s water, which increases the risk of damage.

Can PEX be used for expansion tank?

Cut a piece of PEX to run between the expansion tank and the tee-fitting that you inserted in the hot water tank cold water supply line. If you have other fittings between the two, you will need to cut pieces of PEX to connect those as well.

Can you install expansion tank upside down?





Expansion tanks can be installed in any direction. Whether oriented uprightly, horizontally, or even upside down, the expansion tank will function properly without any adverse effects.

How often should an expansion tank be replaced?

Between five and 10 years

Between five and 10 years is the average lifespan of your tank. If your home’s water pressure matches the air pressure in your expansion tank, you can extend the life of your tank. You’ll need to replace it in some cases.

How do you know when an expansion tank is bad?

If your Thermal Expansion Tank is hanging from a pipe, you would push the Schrader Valve (air valve), located on the bottom of the tank, if the air is released then the tank is working properly. If nothing or water comes out your tank is bad and needs to be replaced.

How do I stop my expansion tank from leaking?



The only way to fix this type of leak is by opening the pipe joints and dry any water around the joints. With a cleaning agent and a scratcher pad, preferably plastic, carefully clean the threads on the pipe and joints. Cover the threads of the pipe with plumber’s putty and screw into the joint.

Why is my expansion tank leaking water?

And sometimes, as water expands after being heated, it outgrows the space within the tank. When this happens, excess water is immediately sent to the expansion tank to lower pressure levels inside the water heater. But sometimes, due to wear and tear, your expansion tank may start leaking.

Why is my expansion vessel leaking?

The expansion vessel acts as a buffer for the boiler when the pressure gets too much. So, if the expansion vessel has stopped working, the pressure is forced elsewhere, and this is what causes the leak. As mentioned, this pressure is usually transferred to the auto air vent.

How long does an expansion tank last?



Between five and 10 years

Expansion tanks can wear out. Between five and 10 years is the average life of your tank. If your home’s water pressure matches the air pressure in your expansion tank, you can extend its life. You will need to replace it in some cases.

What water line does an expansion tank go on?

Although expansion tanks can be installed on the hot side, we strongly recommend they be installed on the cold line, downstream of the shutoff valve.

How do you maintain an expansion tank?

Is There Maintenance on Expansion Tanks? A hydronic system should be completely closed. There should be no leaks and the cold fill pressure should remain constant at room temperature. The PRV should not need to be adjusted.

How much does it cost to replace a water heater expansion tank?



FAQs About Hot Water Heater Expansion Tanks

You may be able to go six to 12 years or more before needing to replace your expansion tank. At $90 to $350, hot water heater expansion tanks are usually much more affordable than the cost of hot water tanks themselves, which average about $1,190.

What does an expansion tank cost?

Expect to pay anywhere from $40 to $200, or about $120 on average, for a water heater expansion tank. The price varies based on the tank size. What is this? On average, residential homes with 40- to 50-gallon water heaters use a 2-gallon water heater expansion tank.

How long does it take to install an expansion tank?

Your new tank should be installed by a licensed plumbing professional within 2 hours.