On Aug 20, 5:49*am, wrote:
On Aug 19, 8:46*pm, fftt wrote:
On Aug 19, 7:26*am, Phisherman wrote:
On Tue, 18 Aug 2009 23:40:17 -0700 (PDT), fftt
wrote:
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
That explains it, thanks. *The tank is charged to 40psi, so when a
faucet is opened the expansion tank is preventing the pipe pressure
from falling below 40 psi. *Before the expansion tank installation, a
faucet would temporarily lose some pressure. *I guess this is a
benefit of the tank, but it's real purpose is to allow water to go
somewhere instead of an increase in pressure on the lines and inside
the water heater tank. *
yes, since ...worst case oyu could have a whole water heater of cold
water (all the hot got used up)
the water is heated and expands by xx%
if NO hot water is used during the heating process....than depending
on the "cold" to "hot" temperature delta, on a 40 gal W/H you get
about 1 galllon of expansison.
I think that a lot installs use a tank that is too small & probably
are under pressurized as well.
I discussed my install with my plumber & I opted for an adjustable
relief valve set to ~80psi instead of an expansion tank.
The system dumps a less then a few quarts per day into a flower bed
Sounds like a poor solution to me. * Here in NJ, expansion tanks are
generally not used on systems with municipal water and they pass
inspection and cause no problems. * * If the pressure in the system is
spiking to over 80PSI, I'd put in a pressure regulator to fix the
problem the right way, which would allow the pressure to be set at a
more normal 50-60 PSI for the house.
here;s a link to a sizing discussion
http://wwwboard.masterplumbers.com/p.../Boyleslaw.asp
Sounds like a poor solution to me.
what exactly are refering to with your comment "Sounds like a poor
solution to me" ?
In NJ, is some sort of posiive backflow preventor required on
residential water services?
If back flow prevention is installed without a properly sized
expansion tank or a relief valve set below T&P valve's activation
pressure, how is eventual system over pressure caused by thermal
expansion handled?
cheers
Bob