I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

On Jul 19, 9:16*pm, blueman wrote:
I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

My understanding & experience is that an expansion tank is only needed
when your house is isolated from city supply by some sort of backflow
prevention device.

With such a device installed, cold water coming into your system to
replace hot water consumed & being heated by the water heater can
generate enough pressure to pop your water heater T&P valve.

The only signifant "give" in your systems is back flow into the city
main. If you have a back flow prevention device then you need a
relief valve (set higher than citty pressure plus hammer spikes &
lower than water heater Y&P valve) or an expansion tank.

If oyu have an open system (backk flow into main) forget the expansion
tank....not gonna do much.


cheers
Bob

"blueman" wrote in message
...


Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve in
the water meter? If yes, then you must have an expansion tank otherwise the
T&P valve on the water heater will get a lot of use. Water expands when it's
heated, it has to go somewhere.

If there's no anti-backflow valve in the system, don't bother with an
expansion tank.

blueman wrote:
I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

it's required only if you have a backflow preventer or check valve on
your water supply. A pressure reducing valve usually acts as a BFP as
well, so that counts.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Jul 20, 7:41�pm, Nate Nagel wrote:
blueman wrote:
I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

it's required only if you have a backflow preventer or check valve on
your water supply. �A pressure reducing valve usually acts as a BFP as
well, so that counts.

nate

--
replace "roosters" with "cox" to reply.http://members.cox.net/njnagel- Hide quoted text -

- Show quoted text -

Allegheny county in pittsburgh PA added pressure tank as mandatory
with all new water heater installs

They are also trying to require anti backflow valves be installed
espically at home resale time

On Mon, 20 Jul 2009 00:16:32 -0400, blueman wrote:

I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

Many jurisdictions are putting in backflow prevention at the meter.
If yours has such you will need an expansion tank. We didn't have one
for a few years, and it was definitely hard on fixtures.

"Bob M." writes:

"blueman" wrote in message
...


Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.

If yes, then you must have an expansion tank
otherwise the T&P valve on the water heater will get a lot of
use. Water expands when it's heated, it has to go somewhere.

If there's no anti-backflow valve in the system, don't bother with an
expansion tank.

Makes sense...

Nate Nagel writes:

blueman wrote:
I was just reading an article about the "importance" of a thermal
expansion tank to extend the lifetime of water heaters, T&P release
valves, hot water fixtures, etc.

On the other hand, we have never had one in our house or where I grew
up and I haven't "noticed" any problems.

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Alternatively, is there enough "give" either forward through the hot
water plumbing or backward through the cold water plumbing (and
ultimately maybe even back into the city mains) to allow sufficient
room for expansion?

If a thermal expansion tank is recommended, any suggestions on brands,
models and sizes?

it's required only if you have a backflow preventer or check valve on
your water supply. A pressure reducing valve usually acts as a BFP as
well, so that counts.


Which is one reason why I am not crazy in getting a pressure reducing
valve even though our static pressure is 85-90 psi.

blueman wrote:
"Bob M." writes:

"blueman" wrote in message
...

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.
85 PSI is pretty high, you may want to invest in a pressure reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?
Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.

If yes, then you must have an expansion tank
otherwise the T&P valve on the water heater will get a lot of
use. Water expands when it's heated, it has to go somewhere.

If there's no anti-backflow valve in the system, don't bother with an
expansion tank.

Makes sense...

With the exception that 85 psi is already on the high side. Do you know
what it is at say 4 AM when city wide usage is light? Ours creeps up to
120+ psi around then. I installed a regulator and a thermal expansion
tank. Both are inexpensive and easy to install. The other think you
notice is the expansion tank buffers little surges nicely.

"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...


Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure reducing
valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.


If your T&P valve on the water heater hasn't sprayed scalding-hot water all
over by now, then you don't have an anti-backflow valve (or DO have
one, -and- an expansion tank). You would know by now.

"Bob M." writes:

"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...


Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure
reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.


If your T&P valve on the water heater hasn't sprayed scalding-hot
water all over by now, then you don't have an anti-backflow valve (or
DO have one, -and- an expansion tank). You would know by now.

Well the water heater is 5 years old and not a drop has come out of
the T&P valve and we definitely don't have an expansion tank... so I
guess e don't have an anti-backflow valve then. Thanks

Bob M. wrote:
"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...


Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure reducing
valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.


If your T&P valve on the water heater hasn't sprayed scalding-hot water
all over by now, then you don't have an anti-backflow valve (or DO have
one, -and- an expansion tank). You would know by now.

I would say that it would indicate a definite maybe or not...

On Jul 21, 10:05*pm, blueman wrote:
"Bob M." writes:
"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure
reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.

If your T&P valve on the water heater hasn't sprayed scalding-hot
water all over by now, then you don't have an anti-backflow valve (or
DO have one, -and- an expansion tank). *You would know by now.

Well the water heater is 5 years old and not a drop has come out of
the T&P valve and we definitely don't have an expansion tank... so I
guess e don't have an anti-backflow valve then. Thanks

Buy this gauge http://www.watts.com/pro/_productsFu...?pid=647&ref=1
at Home Depot
for about $12.

Put it on the drain of your water heater and open the drain valve. If
the tattletale needle indicates
over 90lbs the next day you have a closed plumbing system and need a
thermal expansion tank.

More info on thermal expansion here...
http://www.watts.com/pro/divisions/w...n.asp?catId=64

justalurker justalurker writes:
On Jul 21, 10:05*pm, blueman wrote:
"Bob M." writes:
"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure
reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.

If your T&P valve on the water heater hasn't sprayed scalding-hot
water all over by now, then you don't have an anti-backflow valve (or
DO have one, -and- an expansion tank). *You would know by now.

Well the water heater is 5 years old and not a drop has come out of
the T&P valve and we definitely don't have an expansion tank... so I
guess e don't have an anti-backflow valve then. Thanks

Buy this gauge http://www.watts.com/pro/_productsFu...?pid=647&ref=1
at Home Depot
for about $12.

Put it on the drain of your water heater and open the drain valve. If
the tattletale needle indicates
over 90lbs the next day you have a closed plumbing system and need a
thermal expansion tank.

That's a great idea and I already have one of those gauges anyway
screwed into a garden hose fitting right off my main cold supply so
shouldn't be too hard to move it to the hot supply.

Though based on my understanding, it should be sufficient to keep the
gauge on the cold supply since the piping between the cold inlet
(after the valve) and the water heater is an open system (without
intervening valves) with relatively large caliber pipe (1" and 3/4")
so the pressure on the hot water tank should be pretty close to the
pressure on the T&P valve. In fact, the whole danger of thermal
expansion is presumably that the pressure (and associated wear & tear)
is transmitted to all the fixtures on your system and if the pressure
can be transmitted forward from the hot water tank 50-100 feet to
faucets then the same pressure should certainly be transmitted
backwards 10-20 feet to the pressure gauge on my main water line.

So in summary, I am assuming that if the pressure on my main line
doesn't spike up much beyond the baseline then I probably don't need a
thermal expansion tank.

Does this make sense or am I missing something...

Also, now that I think of it, even if I did have a backflow preventer
without an expansion tank, there probably is a fair bit of reserve
"capacitance" in the overall system given that the house is relatively
large (bathrooms on the 3 floors plus basement) and also there is an
attached in-ground sprinkler system with probably couple of hundred
feet of 1" poly distribution piping (even with all the valves closed)
-- also the poly piping is more flexible/expansible than copper. Of
course during the winter with the irrigation system shut off there is
less reserve capacitance since you only have the rigid copper piping
inside the house.

More info on thermal expansion here...
http://www.watts.com/pro/divisions/w...n.asp?catId=64

blueman wrote:
justalurker justalurker writes:
On Jul 21, 10:05 pm, blueman wrote:
"Bob M." writes:
"blueman" wrote in message
...
"Bob M." writes:
"blueman" wrote in message
...
Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.
85 PSI is pretty high, you may want to invest in a pressure
reducing valve.
How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?
Depends on your city water system. Do they have an anti-backflow valve
in the water meter?
I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.
If your T&P valve on the water heater hasn't sprayed scalding-hot
water all over by now, then you don't have an anti-backflow valve (or
DO have one, -and- an expansion tank). You would know by now.
Well the water heater is 5 years old and not a drop has come out of
the T&P valve and we definitely don't have an expansion tank... so I
guess e don't have an anti-backflow valve then. Thanks
Buy this gauge http://www.watts.com/pro/_productsFu...?pid=647&ref=1
at Home Depot
for about $12.

Put it on the drain of your water heater and open the drain valve. If
the tattletale needle indicates
over 90lbs the next day you have a closed plumbing system and need a
thermal expansion tank.

That's a great idea and I already have one of those gauges anyway
screwed into a garden hose fitting right off my main cold supply so
shouldn't be too hard to move it to the hot supply.

don't bother then. in fact, unless you're one of those people who flush
your water heater tank every year, and/or you have a high end water
heater with a real "boiler drain" or ball valve for a drain valve, that
might cause more problems than it's worth.

I have replaced all the water heater drain valves at my house (there's
three...) with dielectric nipples, 3/4" threaded ball valves, and a 3/4"
MIP to garden hose thread adapter (with a brass cap on the end for
safety) due to having had problems with every blame one of them when I
attempted to do my first annual flush after moving in.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

On Jul 22, 4:27*pm, blueman wrote:
justalurker justalurker writes:
On Jul 21, 10:05*pm, blueman wrote:
"Bob M." writes:
"blueman" wrote in message
...
"Bob M." writes:

"blueman" wrote in message
...

Specifically, we have a 40 gallon gas-fired water heater on city water
with 3/4" inlet and outlet to the water heater and copper plumbing
throughout the house. We have 4 bathrooms and a kitchen. The city
water pressure comes in at about 85 PSI.

85 PSI is pretty high, you may want to invest in a pressure
reducing valve.

How important is it to add a thermal expansion tank or is this one of
those "if it ain't broke, don't fix it" kind of things?

Depends on your city water system. Do they have an anti-backflow valve
in the water meter?

I am not aware that there is an anti-backflow valve though I imagine
it could be built into the meter (which is one of those electronic
ones that they then broadcast wirelessly). Is there any easy way to
check by looking or would I need to call the city and/or try to find
and look up a model number.

If your T&P valve on the water heater hasn't sprayed scalding-hot
water all over by now, then you don't have an anti-backflow valve (or
DO have one, -and- an expansion tank). *You would know by now.

Well the water heater is 5 years old and not a drop has come out of
the T&P valve and we definitely don't have an expansion tank... so I
guess e don't have an anti-backflow valve then. Thanks

Buy this gaugehttp://www.watts.com/pro/_productsFull.asp?pid=647&ref=1
at Home Depot
for about $12.

Put it on the drain of your water heater and open the drain valve. If
the tattletale needle indicates
over 90lbs the next day you have a closed plumbing system and need a
thermal expansion tank.

That's a great idea and I already have one of those gauges anyway
screwed into a garden hose fitting right off my main cold supply so
shouldn't be too hard to move it to the hot supply.

Though based on my understanding, it should be sufficient to keep the
gauge on the cold supply since the piping between the cold inlet
(after the valve) and the water heater is an open system (without
intervening valves) with relatively large caliber pipe (1" and 3/4")
so the pressure on the hot water tank should be pretty close to the
pressure on the T&P valve. In fact, the whole danger of thermal
expansion is presumably that the pressure (and associated wear & tear)
is transmitted to all the fixtures on your system and if the pressure
can be transmitted forward from the hot water tank 50-100 feet to
faucets then the same pressure should certainly be transmitted
backwards 10-20 feet to the pressure gauge on my main water line.

So in summary, I am assuming that if the pressure on my main line
doesn't spike up much beyond the baseline then I probably don't need a
thermal expansion tank.

Does this make sense or am I missing something...

Also, now that I think of it, even if I did have a backflow preventer
without an expansion tank, there probably is a fair bit of reserve
"capacitance" in the overall system given that the house is relatively
large (bathrooms on the 3 floors plus basement) and also there is an
attached in-ground sprinkler system with probably couple of hundred
feet of 1" poly distribution piping (even with all the valves closed)
-- also the poly piping is more flexible/expansible than copper. Of
course during the winter with the irrigation system shut off there is
less reserve capacitance since you only have the rigid copper piping
inside the house.

More info on thermal expansion here...
http://www.watts.com/pro/divisions/w...rol/learnabout...

You can leave that gauge on the cold side as long as that bib has
service pressure on it.
Take a bath or shower before you go to bed. The water heater will
fire and as long as you don't open a
faucet or flush the toilet and relieve the pressure you'll get a
surprise on that gauge in the morning (or just stand there and watch
it till the WH shuts off.

If you have a closed plumbing system you'll see pressures up around
130-140psi on the tattletale needle.

If that is the case you need a thermal expansion tank.

BTW, that excessive pressure of thermal expansion is at every pipe,
fitting, appliance, and valve in your system and most pluming fixtures
are rated to only 80psi... just a thought.

There is NOT sufficient "reserve capacitance" in any plumbing system
to absorb water expansion @ 140psi.
Well, there's some "reserve capacitance"... it's leaking faucets,
running toilets, blown pipes, leaking fittings, and a T&P valve. Water
is not progressively compressible as air is. Double the pressure and
water will go somewhere...
and most of the somewheres waste money or cost lots of money to fix.

On Wed, 22 Jul 2009 18:27:33 -0400, blueman wrote
Re Thermal Expansion tank for water heater - is it necessary?:

So in summary, I am assuming that if the pressure on my main line
doesn't spike up much beyond the baseline then I probably don't need a
thermal expansion tank.

Correct.
--
I filter all messages from google groups.

replying to fftt, dp3 wrote:
Even if the system is closed I would ask of the expansion of the steel tank
itself somewhat matches any water expansion? additionally if there is a
anti-water-hammer device (i.e., shock absorber) anywhere in the system (often
found at washing machine or shower or sometimes whole house - simply a
vertical pipe filled with air) then I wuold think a thermal expansion tank is
not actually needed.

--
for full context, visit https://www.homeownershub.com/mainte...ry-384734-.htm

replying to Chris Hill, Bobby wrote:
No hard and fast rules. I have one in this house, never did in my old one.
My water pressure is 70 psi. When the water heats and is not running, pressure
will go up to 100 psi. At that point the PRV will weep a bit. It would leak
about a pint to a quart in a day depending on use. If you have any leak,
put in the expansion tank. If no leak, not to worry,

--
for full context, visit https://www.homeownershub.com/mainte...ry-384734-.htm

The guy ffft from a decade ago hit it.

replying to blueman, tony wrote:
I do not see any benefits on the hot water heater. However if that was heater
for house that would be different story. No expansion thank for water heater
is unnecessary it will do nothing for you, 40 gallon water heater is little
small for that size of house.

--
for full context, visit https://www.homeownershub.com/mainte...ry-384734-.htm

On Sunday, February 5, 2017 at 2:44:15 PM UTC-5, dp3 wrote:
replying to fftt, dp3 wrote:
Even if the system is closed I would ask of the expansion of the steel tank
itself somewhat matches any water expansion? additionally if there is a
anti-water-hammer device (i.e., shock absorber) anywhere in the system (often
found at washing machine or shower or sometimes whole house - simply a
vertical pipe filled with air) then I wuold think a thermal expansion tank is
not actually needed.

A vertical pipe filled with air isn't going to stay filled with air
for long. The air winds up dissolving into the water under pressure.
That's why water storage tanks on pumps need either a mechanism to
inject air as needed or a plastic bladder to separate the air and
water.

On Sunday, February 5, 2017 at 9:44:05 PM UTC-5, tony wrote:
replying to blueman, tony wrote:
I do not see any benefits on the hot water heater.

He just said that without an expansion tank, the pressure goes
up to 100 PSI and the TPR valve starts leaking.




However if that was heater
for house that would be different story. No expansion thank for water heater
is unnecessary it will do nothing for you,

See above.

On 2/5/2017 3:14 PM, Bobby wrote:
replying to Chris Hill, Bobby wrote: No hard and fast rules. I have
one in this house, never did in my old one. My water pressure is 70
psi. When the water heats and is not running, pressure will go up to
100 psi. At that point the PRV will weep a bit. It would leak
about a pint to a quart in a day depending on use. If you have
any leak, put in the expansion tank. If no leak, not to worry,

When I moved into my house there was an expansion tank. When I
had the hot water heater replaced recently the guy removed the expansion
tank. When I questioned this he said the new water heater was designed
to not need one. He was apparently right since the pressure does remain
constant throughout the cycle.

BTW I'm late to the thread so please excuse if already covered.

On 2/6/2017 8:29 AM, trader_4 wrote:
On Sunday, February 5, 2017 at 9:44:05 PM UTC-5, tony wrote:
replying to blueman, tony wrote:
I do not see any benefits on the hot water heater.

He just said that without an expansion tank, the pressure goes
up to 100 PSI and the TPR valve starts leaking.

I solved that issue by removing my TPR Valve.

trader_4 wrote:
On Sunday, February 5, 2017 at 2:44:15 PM UTC-5, dp3 wrote:
replying to fftt, dp3 wrote:
Even if the system is closed I would ask of the expansion of the steel tank
itself somewhat matches any water expansion? additionally if there is a
anti-water-hammer device (i.e., shock absorber) anywhere in the system (often
found at washing machine or shower or sometimes whole house - simply a
vertical pipe filled with air) then I wuold think a thermal expansion tank is
not actually needed.

A vertical pipe filled with air isn't going to stay filled with air
for long. The air winds up dissolving into the water under pressure.
That's why water storage tanks on pumps need either a mechanism to
inject air as needed or a plastic bladder to separate the air and
water.

Took me a while to figure that out. I installed one since my pressure
relief valve kept popping. Thats too many pounds. Don't like the projected
life of only 6 years.

Greg