On Thu, 28 May 2009 22:41:27 -0700 (PDT), fftt
wrote:

On May 28, 7:38Â*pm, John wrote:
The Daring Dufas wrote:
John wrote:
Tom Horne wrote:
Putting a valve on the output line of a hot water heater can lead to
tank damage from water hammer. Â*

How could a valve on the output line possibly cause tank damage? Â*
Maybe if I were to close that valve fast for some reason, but that
would be the case if I closed another hot valve fast.

Many water pressure regulators for homes have check valves
that prevent water from going back to the water meter and
water heaters have check valves in the short pipe nipples
you may see on top of a tank type water heater. The check
valves allow water to flow only in one direction. Water in
the heater expands and the typical home plumbing has enough
room for the expanding water. If not, an expansion tank is
called for. If you were close valves on both hot and cold
connections to the water heater, the T&P safety would open
and flood the floor if it's not piped to a drain. Many water
heaters have a pipe connected to the T&P valve that stops
just above the floor next to the heater. Look at this website
and read the paragraph titled "Thermal expansion". The site
has some good information about water heaters that is easy to understand.

I understand that *operating* a water heater with the valves closed
would be unwise, but one doesn't install a valve on a water heater so
that it can be operated while closed. Â* The valve is for closing when
the water heater is offline to be serviced or replaced. Â*This is like
having a drain plug on a boat, you don't have a drain for when you use
the boat, it is for when the boat is offline/out of the water!

....... I understand that *operating* a water heater with the valves
closed would be unwise......

How is that unwise & more importantly how is that any different than
having all the hot water valves off at the fixtures (normal operating
state)?

cheers
Bob
Opertating the heater with the INLET valve turned off and taps closed
is dangerous.

If the hot water was just used (before closing valves) then
the water in the tank is cold. Water expands as it's heated.
The expansion will force a few drops of water out the TP
valve.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"fftt" wrote in message
...
Possibly damaging the T&P valve. It's a safety valve not
meant to open over and over again. When the valves are
popped open more than a few times, they will tend to start
leaking. Besides, if the valve doesn't go outside or to a
drain, you will wind up with a very wet floor to mop.

TDD

Why is the T/P valve going to open?

It will only open (when both inlet & outlet valves are
closed) IF the
water heater over heats due to a failed thermostat.

T/P valves only open when T or P exceeds limits.......

cheers
Bob

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. Ben 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

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

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

On May 29, 1:16*pm, The Daring Dufas
wrote:
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

My further condolences.....

the breed of "dumb asses" that have access to you & your
installations are way dumber and more persistent than my SoCal "lazy
dumb asses"

I will continue to do my installations per my designs since all my
installations seem to be inaccessible to your types of dumb asses. I
have never suffered from the efforts of your types of dumb asses.
Although I have see some majorly dumb things done .......... not in
the league you describe.

Luck or design? Who knows.......

btw I never mentioned removing the handle on a gate valve.

cheers
Bob

I was in an old country shop, one time. They had a nice neat
wooden plaque that said "in case of fire, lift flap". I did.
Under it, nicely painted, said "I said, IN CASE OF FIRE,
stupid!"

I like you one with the fire horn.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"The Daring Dufas" wrote in
message ...

"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

Loosen nut. Use handle from other side after closing first
side.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"The Daring Dufas" wrote in
message ...

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

fftt wrote:
On May 29, 1:16 pm, The Daring Dufas
wrote:
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

My further condolences.....

the breed of "dumb asses" that have access to you & your
installations are way dumber and more persistent than my SoCal "lazy
dumb asses"

I will continue to do my installations per my designs since all my
installations seem to be inaccessible to your types of dumb asses. I
have never suffered from the efforts of your types of dumb asses.
Although I have see some majorly dumb things done .......... not in
the league you describe.

Luck or design? Who knows.......

btw I never mentioned removing the handle on a gate valve.

cheers
Bob

I know you wrote ball valve, that's easy to turn with
an adjustable wrench but any valve with a relatively
smooth shaft won't stay that way. If you're familiar
with refrigeration valves, you know that some jerk
without a square drive wrench will put vice grips,
pliers or an adjustable wrench on the damn thing and
ruin it.

TDD