How do I know if my expansion tank failed?

Check your relief valve on the water heater. It’s located on the side of the water heater with a tube that goes to the floor. If the relief valve is dripping, this could indicate your expansion tank has failed.

Why is my expansion tank dripping water?





An expansion tank is a small tank that protects closed and domestic water heating systems from excessive pressure. The changes in pressure inside the expansion tank can bring about the degradation of the water heating system and cause leaks.

How do I know if I need a new expansion tank?

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.

What causes boiler expansion tank to leak?

The problem could be a waterlogged expansion tank, over pressure in the system, over temperature in the system, a defective TP valve, or something else. If your tankless coil is leaking into the boiler that’d cause overpressure.

How often should 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 much does it cost to replace an expansion tank?

The job of the thermal expansion tank is to absorb the extra water volume so that the excess pressure does not cause undue wear and tear on the water heater and other fixtures in the home. The cost to install a new Thermal expansion tank can range from $279 to $443.

Should water coming out of expansion tank valve?

It could also indicate that the diaphragm is no longer functional, which means that there is nothing to prevent the water from entering. You can also remove the cover on the underside of the tank and apply pressure to the valve pin. Any water that comes out is a sign that the diaphragm has been damaged.

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.

Does expansion tank affect water pressure?



The expansion tank contains air, which is highly compressible. Expanding water from the water heater can flow into the expansion tank, where the air compresses, making room for the increased volume of water. Water pressure in the system doesn’t increase significantly.

How do you check pressure in an expansion tank?

Check the air pressure in the Expansion Tank using a tire gauge. Adjust the air pressure to equal the maximum water pressure in the home. Use a hand pump – NOT an air compressor – or you may rupture the bladder. turning a hot water faucet on until a steady stream flows.

How much air pressure should be in a hot water 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?



With the required check valves and backflow preventers in place, your water pipes, water heater and even some appliances must deal with the increased pressure caused by thermal expansion. This causes unnecessary wear-and-tear which can result in damage to hot water-use appliances, including your water heater.

What is the difference between an expansion tank and a pressure tank?

The biggest difference between pressure tanks and expansion tanks is in where they’re used. Expansion tanks are installed above a water heater and help to protect it when hot water expands. Pressure tanks are installed near your well pump and help to protect and extend its lifespan.

How do you bleed an expansion tank?

3 Answers

  1. Turn off the valve that auto-fills the system from your cold water line.
  2. If you have one, open a valve or bleeder on the top of your expansion tank. …
  3. Open a drain valve and drain a suitable amount of water.
  4. Close drain valve and re-open valve you closed in step 1.