fftt wrote:
On May 29, 6:51 am, The Daring Dufas
wrote:
fftt wrote:
On May 28, 3:53 pm, The Daring Dufas
wrote:
bob haller wrote:
:
A truly excellent idea. For the moments when the WH is in
the cellar of a frame home.
actually any home, its easier to work without water draining back on
you,
and nearly impossible to solder copper lines with water in them.
2 valves elminate all this.
and what difference does a frame home make?
mine is brick but the water system is the same.
the only time both valves are closed is during tank replacement.....
You are aware of "The Dumb Ass Effect"? You will
know better than to shut off both valves while
the heater is in operation but "some dumb ass"
will come along and turn the damn things off
when they're not supposed to.
TDD
TDD-
What's the big deal if BOTH valves are turned off while the water
heater is in place?
How is that any different than when all the hot water valves at all
the fixtures are off?
The water heater will heat the water to the temperature set by the
thermostat & shut off.......just like it always does.
cheers
Bob
EXPANSION! I've had to install expansion tanks on water
heaters where the plumbing system wasn't large enough to
accommodate the increase in volume when the water is
heated. The T&P valve will pop open all the time until
it starts leaking. I wish I could get my friend who is
a master plumber with many years experience to chime in
to this group. When you've worked in the construction
and service industry for several decades like I have,
you will tend to absorb a lot of knowledge by observing
and asking questions of other people who work in many
different fields and trades. Been there, done that, seen
that applies to anyone who's been around long enough,
unless they're in a coma. "The Dumb Ass Effect" is why
I put locks on valves, safety switches, electrical panels
and a myriad of other devices. Warning signs encourage
dumb asses to play with things. Understanding dumb asses
has provided me with a lot of entertainment. I once hooked
a fire horn to a latching switch that was marked "DO NOT
TOUCH THIS SWITCH". I can't count the number of times I
laughed at some poor moron who just could not resist the
temptation to fiddle with it.

TDD

TDD-

You are correct.....

IF the water heater is cold (ie not at operating temp) WHEN BOTH
valves are closed.....

YES the T/P valve will relieve the pressure due expansion IF BOTH
both remained closed during this "procedure"

and if IF the pressure exceeds the limit of the T/P

btw water heater tanks are not infinitely rigid......I'm too lazy to
calc the volume change from 75 psi to 150


btw this would a one time event unless your "example dumb ass" keep
opening & closing the valve and letting the water.


my condolences for your pain of having to work & interact with dumb
asses

I have fun trying to make things more idiot resistant and since there
are a lot of idiots, I dont run out of fun.

one way to make the two valve installation more idiot
resistant.....remove the handle from the outlet ball valve

cheers
Bob




The problem with removing the handle of a gate valve
is that the dumb asses have discovered vice grips. I
like ball valves with a lock around them. There are
locking enclosures that wrap around valves but the
drain bamaged know how to use chisels and hack saws.
More work for me.

TDD