Expansion Tank, and other water heater questions..........

[JohnPK]

I have 2 50 Gal Bradford White gas water heaters. each has a 2.1 gal expansion tank on top. One of the expansion tanks started leaking. I know to use an expansion tank you measure the water pressure for your home find the appropriate tank and pressurize to that pressure and put it on the water heater. My question is, if I have two water heaters do I split the measured pressure and put that on the expansion tank or do I still pressurize to the full amount, in this case, I measured the pressure on the external faucet at 80 psi. Also, I am guessing you turn off the water heater and drain (flush) it out before replacing the expansion tank?

 

[Reach4]

My question is, if I have two water heaters do I split the measured pressure and put that on the extension tank or do I still pressurize to the full amount, in this case, I measured the pressure on the external faucet at 80 psi.

Each would be 80 PSI.

Also, I am guessing you turn off the water heater and drain (flush) it out before replacing the extension tank?

It is not necesssary to drain the WH. Turn off the valve. Turn the WH off or to vacation mode. Drain a little water.

However it is good to flush the WH at times, so that would be a good time. To do a simple flush,

1. Turn off the water to the WH.
2. drain the WH. Open a hot water faucet to admit air.
3. When empty, turn on the incoming water quickly for several seconds to spray against any sediment on the bottom.
4. Drain the WH.
5. Repeat #3 and #4 a few times.
6. Close the drain
7. Turn the water back on.
8. When water is freely coming out of that open faucet, close the faucet.
9. Turn the WH back on.

 

[Sponsor]

 

[FullySprinklered]

Expansion tank. (Just a word of advice).

 

[JohnPK]

Thank you very much Reach 4 !! and yes, "Expansion tank" thanks

 

[Master Plumber Mark]

you ought to put a larger expansion tank on the units.. the 2.5 is basically
a small wimpy sized peice of crap that I wont use even on a 40 gallon heater..
They always get water logged in a very short while..

. You should get the larger 5 gallon
big boy and install it on the units if you have the space to do it....

 

[hj]

IF, your tanks are getting "water logged in a short time", you are using defective tanks, because the only way they can get water logged is if the diaphragm breaks so the air is absorbed by the water and the water fills the tank, or the air leaks out and water fills the tank. NEITHER of which can happen with a good, functioning tank. It does not take much expansion to create a big change in pressure, so the size of the tank is somewhat immaterial.

 

[Reach4]

It does not take much expansion to create a big change in pressure, so the size of the tank is somewhat immaterial.

It is going to take a bigger tank in Indianapolis than in Phoenix.

 

[Jadnashua]

There is more than one free on-line ET size calculator tool. One larger than needed will only cost you a bit more, but one too small will fail more often. Not precharging it properly can kill it faster, though.

 

[Master Plumber Mark]

IF, your tanks are getting "water logged in a short time", you are using defective tanks, because the only way they can get water logged is if the diaphragm breaks so the air is absorbed by the water and the water fills the tank, or the air leaks out and water fills the tank. NEITHER of which can happen with a good, functioning tank. It does not take much expansion to create a big change in pressure, so the size of the tank is somewhat immaterial.

Just hold your horses...here hj... I dont know how you determine which brands of thermal expansion
tanks are better than others...?? I do know that the smaller ones seem to get overwhelmed faster than
the larger ones.. I have seen it many times... and I have seen the larger ones get water logged after 10+ years too..
They weigh a ton and will just about take you out when you detach one....

so please go ahead and educate me as to which brand you buy at the supply house that is
a better quality than others.... (this is like choosing condoms in my opinion)