Don Y wrote in :

On 11/22/2015 11:51 AM, Doug Miller wrote:
Don Y wrote in :

On 11/22/2015 7:06 AM, Doug Miller wrote:
Don Y wrote in :

On 11/21/2015 5:20 PM, Doug Miller wrote:
Don Y wrote in news:n2qc5h$41c$1@dont-
email.me:

On 11/21/2015 10:55 AM, Doug Miller wrote:
Micky wrote in
news:n3605btdvs9avi246kpt1j8vvfrfptkeas@
4ax.com:

How did we get along without these tanks for so many years?

Because for many years, municipalities allowed the sort of behavior described
by
Don
Y -- if
the pressure in the residential system rises above the supply pressure, water will
be
forced
out of the residence and into the supply.

This is now prohibited in many locations, and homes are required to have
backflow
preventers to insure that this cannot happen.

Heated water has to expand somewhere, and if it can't expand into the municipal
supply,
you'd better have an expansion tank.

You can find lots of videos "exploding water heaters". There's a lot
of pent-up pressure in those systems and the heater is often the weakest
link.

And that has absolutely nothing to do with expansion tanks. Water heaters explode
due
to a
combination of runaway heating *and* a failed temperature-pressure relief valve. If
*that*
happens, no expansion tank is going to contain the enormous increase in pressure
that
precedes a catastrophic steam explosion.

Water heaters explode due to the fact that water EXPANDS when heated.

False. Water heaters explode due to the fact that water expands by several orders of
magnitude when it is BOILED. Simple thermal expansion of water due to heating in
normal
operation does not cause water heaters to explode.

Do you know how to boil water *without* HEATING it? (bring the tank into
the vacuum of space??)

Are you aware that water can be heated WITHOUT boiling it?

And, does it NOT expand??

Of course it expands -- but not nearly enough to cause an explosion, unless it boils.

On Monday, November 23, 2015 at 10:05:24 PM UTC-5, Doug Miller wrote:
Don Y wrote in :

On 11/22/2015 11:51 AM, Doug Miller wrote:
Don Y wrote in :

On 11/22/2015 7:06 AM, Doug Miller wrote:
Don Y wrote in :

On 11/21/2015 5:20 PM, Doug Miller wrote:
Don Y wrote in news:n2qc5h$41c$1@dont-
email.me:

On 11/21/2015 10:55 AM, Doug Miller wrote:
Micky wrote in
news:n3605btdvs9avi246kpt1j8vvfrfptkeas@
4ax.com:

How did we get along without these tanks for so many years?

Because for many years, municipalities allowed the sort of behavior described
by
Don
Y -- if
the pressure in the residential system rises above the supply pressure, water will
be
forced
out of the residence and into the supply.

This is now prohibited in many locations, and homes are required to have
backflow
preventers to insure that this cannot happen.

Heated water has to expand somewhere, and if it can't expand into the municipal
supply,
you'd better have an expansion tank.

You can find lots of videos "exploding water heaters". There's a lot
of pent-up pressure in those systems and the heater is often the weakest
link.

And that has absolutely nothing to do with expansion tanks. Water heaters explode
due
to a
combination of runaway heating *and* a failed temperature-pressure relief valve. If
*that*
happens, no expansion tank is going to contain the enormous increase in pressure
that
precedes a catastrophic steam explosion.

Water heaters explode due to the fact that water EXPANDS when heated.

False. Water heaters explode due to the fact that water expands by several orders of
magnitude when it is BOILED. Simple thermal expansion of water due to heating in
normal
operation does not cause water heaters to explode.

Do you know how to boil water *without* HEATING it? (bring the tank into
the vacuum of space??)

Are you aware that water can be heated WITHOUT boiling it?

And, does it NOT expand??

Of course it expands -- but not nearly enough to cause an explosion, unless it boils.

Also, as I pointed out previously, water isn't the only thing that
expands when heated. The steel tank does too, increasing it's volume.

On 11/20/2015 4:48 PM, Walter E. wrote:

I installed a pressure regulation valve in my city water supply because
city pressure is 120 psi. This turned my house piping system into a
"closed system" with no place for the pressure and added volume to go.
This results in water pressure of 150 lbs, which damages my appliances.
Turns out that I now need an expansion tank to absorb the volume and
pressure created by the water being heated. The plumbers I talked to
cannot agree on what I should do:

I have one water HEATER each to supply water to the front and rear of
our home (2 heaters). Both water HEATERS seem to be connected by pipes
to ONE water SOFTENER that supplies both areas (front and back of the
house) with hot, soft water.

How do I install the water heater expansion tank(s)?

Do I install one small expansion tank at one of the heaters, based on
the specs for that heater only (40 gal and 40 lbs pressure), or should I
install a larger expansion tank at the first water heater to allow for
the second and more remote heater, or should I get two small expansion
tanks, one at each heater?

Both heaters are 40 gal and the house pressure is set for 40 psi.

I don't think it matters, one large one or two small ones. I'd probably
opt for two small ones.

On Sat, 21 Nov 2015 14:46:48 -0800 (PST), bob haller
wrote:

On Saturday, November 21, 2015 at 2:08:07 PM UTC-5, Micky wrote:
On Sat, 21 Nov 2015 17:55:45 -0000 (UTC), Doug Miller
wrote:

Micky wrote in news:n3605btdvs9avi246kpt1j8vvfrfptkeas@
4ax.com:

How did we get along without these tanks for so many years?

For the record, I'm not talking about the pressure valve. I can see
that that's a good thing, and the house was built with one, which
hasn't required a bit of maintenance in 36 years.

Because for many years, municipalities allowed the sort of behavior described by Don Y -- if
the pressure in the residential system rises above the supply pressure, water will be forced
out of the residence and into the supply.

This is now prohibited in many locations, and homes are required to have backflow
preventers to insure that this cannot happen.

Heated water has to expand somewhere, and if it can't expand into the municipal supply,
you'd better have an expansion tank.

But what's wrong with my water going into the city supply. It's the
same water they gave me in the first place. If it was good enough
for me, why isn't it good enough for them again? Do they think I
squeezed into the pipes and poisoned it?

And even if it does back up, is it going to back up all the way
through my basement, under the front yard to the water main? Seems
to me it will back up no more than 20 feet, and when I use the water
again, the backed up water will come back into my own house.

the reason for anti backflow prevention.....

lets say you have a garden hose filling your swimming pool. the main fails and the input pressure is now zero.

your icky pool water now siphons into the main all the way to your neighbors, they drink it and can get very ill

That would be terrible.

But I have nothing like that. I have a garden hose I use for less
than 2 hours a year, and when i use it, it just has a nozzle and no
container to siphon from.

Micky wrote:
On Sat, 21 Nov 2015 14:46:48 -0800 (PST), bob haller
wrote:

On Saturday, November 21, 2015 at 2:08:07 PM UTC-5, Micky wrote:
On Sat, 21 Nov 2015 17:55:45 -0000 (UTC), Doug Miller
wrote:

Micky wrote in news:n3605btdvs9avi246kpt1j8vvfrfptkeas@
4ax.com:

How did we get along without these tanks for so many years?

For the record, I'm not talking about the pressure valve. I can see
that that's a good thing, and the house was built with one, which
hasn't required a bit of maintenance in 36 years.

Because for many years, municipalities allowed the sort of behavior
described by Don Y -- if
the pressure in the residential system rises above the supply
pressure, water will be forced
out of the residence and into the supply.

This is now prohibited in many locations, and homes are required to have backflow
preventers to insure that this cannot happen.

Heated water has to expand somewhere, and if it can't expand into the municipal supply,
you'd better have an expansion tank.

But what's wrong with my water going into the city supply. It's the
same water they gave me in the first place. If it was good enough
for me, why isn't it good enough for them again? Do they think I
squeezed into the pipes and poisoned it?

And even if it does back up, is it going to back up all the way
through my basement, under the front yard to the water main? Seems
to me it will back up no more than 20 feet, and when I use the water
again, the backed up water will come back into my own house.

the reason for anti backflow prevention.....

lets say you have a garden hose filling your swimming pool. the main
fails and the input pressure is now zero.

your icky pool water now siphons into the main all the way to your
neighbors, they drink it and can get very ill

That would be terrible.

But I have nothing like that. I have a garden hose I use for less
than 2 hours a year, and when i use it, it just has a nozzle and no
container to siphon from.

Water was off one day for 3 hours working on line own street. Told us to
open big sink cold water spigots to clear the air out of the lines. The
water was nasty brown. I guess that normal for old lines.

Greg