On Aug 18, 4:55*pm, Phisherman wrote:
I installed an expansion water tank when GE stated the warranty on the
water heater is void without one. * So, I charge the tank to 40psi as
stated and installed it fairly easily. *I'm on city water at about
70psi. *I noticed now that when the water is turned on anywhere in the
house, that a burst of water comes out the first couple seconds. *I
notice this most on the kitchen vegetable sprayer and both showers. *I
suppose this is supposed to happen, but it does not explain why.
Expansion tanks are supposed to help preserve water appliances.



The "why" is ......... an expansion tank is hydraulic bladder style
accumulator

There is a badder that keeps the water & air separated.

When you buy one it might be pre-charged to 40 to 50 psi. Or you
might have to pressurize to those levels.

When the unit installed & the water turned back on, the water at city
pressure (like 55 to 75psi) will flow into the accumulator driving the
air pressure up to the same as water pressure.'

Now you a pressurized system over air "over" water.


When you turn on a faucet, the water pressure in the system drops
slightly and the accumulator "squeezes" out some water to service the
demand. This will continue until the accumulator is empty.

cheers
Bob