Hot water Boiler Expansion tank

	For the most part Amtrol expansion tank is the most commonly used expansion tank.
	There are other Brands out there and the work much the same. For most Residential Boilers the following 4 tanks are mostly used.The # 30, the # 110, the # 15, and the #109. Some larger homes need the #60
	And they get much larger but this page is for Home owners. So I will not bother with the larger tanks. Replacing An expansion tank can be very easy in most cases, but you are dealing with VERY hot water and you can get scalded. It may be best to have a heating contractor do it. but like the one I did on the Weil McLain boiler, turned out to be a real pain.

Before I get into how to replace it, I should ask, does it really need to be replaced?

If it is leaking, then it's simple, It needs to be replaced. See Boiler relief valve

If it is full of water, it needs to be replaced, Tap the tank the back should sound hollow, if not, it is full. if it is full, that means it will be very heavy, So be careful not to let drop on your fingers when you remove it.

If there is no air pressure in the tank. use an air gauge you should have 12 psi. But remember you let air out every time you test it. If it does not have 12 psi you can pump it up to 12 psi with a pump. But this is just a temporary patch and it will go flat again. so it should be replaced.
Although a water logged Expansion tank will cause a relief valve on a boiler to leak and /or blow off. It is not the only reason the relief valve leaks and or blows off.
See why is my relief valve leaking? by clicking here

Please click on the link below for the rest of the boiler expansion tank instructions.
This website is designed and run by: Thomas Petito Reardon: a Master Plumber.

Troubleshoot your boiler expansion tank.