Potable Expansion Tank squirting water !!

I have a electric water heater that has a blue 2 gal expansion tank installed vertically on top of the water heater. I believe its connected to cold water line.

It is rusted on the bottom and has sprung a steady leak via some pin sized holes.

So, I purchased a new tank from Lowes for $50 but need help with install.

Can I simply turn off water heater, turn off water supply, then unscrew old one and screw on new one? or, are there additional steps?

The tank is pre-charged to 25 PSI - do i need to change this to match my water heater pressure? how do i measure this and where ?

#1 check house water pressure and fill new tank with air until it is equal to or 1-2 pounds lower than your house water pressure.

#2 turn off water to home.

#3 open hot and cold on lowest and highest faucet and let out all water until it stops.

#4 close both faucets

#5 Unscrew old tank and install new tank...use Teflon tape and pipe dope on threads..

#6 Turn water back on.,...

Cass said:

#3 open hot and cold on lowest and highest faucet and let out all water until it stops.
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Click to expand...

What is the "lowest and highest faucet" mean? Is this in terms of height level in relation to the ground ? (ie. upstairs bedroom is highest, and downstairs is lowest)

Thanks for the step by step!

Yes, the objective is to drain the water from the line so when you effectively put a hole in it by removing the tank, you don't get soaked from the water trapped in the lines. By opening a high and low faucet in the building, you let air in from the top and drain water out from the bottom. You don't have to, but unless you need a cold shower, this will help. The tank, if it is leaking, will be nearly full of water and quite heavy, so be careful unscrewing it so you don't drop it or damage the threads of the fitting.

thanks guys - I was able to put it in with your instructions !