Water heater pressure

[Jadnashua]

I'd put the nominal 60# of pressure in the tank. TO check and adjust that, you need to release the water pressure (i.e., shut off the water and open a valve somewhere), otherwise, when measuring with a gauge, it will read the same as the water pressure. By putting in less than your normal pressure, you're causing it to store some water all of the time, and decreasing it's ability to store the execess caused by expansion.

 

[dmax56]

Jim,

Thanks again. On the pressure...

When my faucet is open, I read 52 psi from gauge in water heater drain valve. I put that in the expansion tank.

Now, the highest pressure I read is 60 psi, even when the heater is on. Before, I'd had 112.

So, should I match the pressure of the hot water heater...i.e. pump it up a few pounds more?

I'm not sure whether the psi when the system is flowing is the same as when it's closed or not, and not sure which pressure to match...though I'm very close to being done with this project!

Doug

 

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[Jadnashua]

Measure the static pressure...no flow. Set it to that.

 

[SteveW]

One thing I did when I put mine in was to add a boiler valve and a quarter-turn ball valve. The ball valve lets me isolate the expansion tank (so I can easily replace it when it eventually fails) and the boiler valve gives me a place to screw in a pressure gauge. It is also kind of interesting to isolate the tank, then run some hot water for a couple minutes, then shut off the faucet and watch the pressure gauge creep up ... up ... up as the water heater heats the slug of cold water.

Once it gets as high as it's going to get, you can then open the ball valve to bring the expansion tank back online, and watch the pressure go down immediately.

As HJ and others have said on this site before, the actually movement of water in and out of the tank is a very small volume - probably less than a cup - but what a difference it makes!