Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Here is a simple quick explanation of the issues:
http://www.askthebuilder.com/B192_Wa...n_Tanks_.shtml

Use of expansion tanks on hot water heaters is fairly common.

--
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




"Theo" wrote in message
...
Recently replaced old electric water heater with a 40-gallon
SuperStor running off oil furnace. It now overpressures and
vents several times a week. Feed pressure is about 30 PSI. A
cheap max-indicating pressure gauge confirms that pressure jumps
whenever a lot of hot water is used, though it doesn't always
reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water
expanding from 55F to 140F is going to strain the pipes in this
small house, and that some kind of expansion tank (like the one
in the heating system, right next to the SuperStor) is needed.
They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

On Aug 2, 7:29*am, Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.

On Sat 02 Aug 2008 05:58:29a, ransley told us...

On Aug 2, 7:29*am, Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.


If you run a dishwasher you need 140°F water for optimum operation. If you
wash white cotton fabric in the clothes washer, you need similar
temperatures. Believe it or not.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

On Aug 2, 9:10*am, Wayne Boatwright wrote:
On Sat 02 Aug 2008 05:58:29a, ransley told us...





On Aug 2, 7:29*am, Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.

If you run a dishwasher you need 140°F water for optimum operation. *If you
wash white cotton fabric in the clothes washer, you need similar
temperatures. *Believe it or not.

--
* * * * * * *Wayne Boatwright * * * * * *
-------------------------------------------
* * *Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
* *Don't start an argument with somebody *
* *who has a microphone when you don't; *
* * they'll make you look like chopped * *
* *liver. --Harlan Ellison, on hecklers *
-------------------------------------------- Hide quoted text -

- Show quoted text -

Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.

there should always be an expansion tank. Especially if you are on some
kind of pressure regulator, or if your city meter has an antibackflow valve
in it.

s


"Theo" wrote in message
...
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure gauge
confirms that pressure jumps whenever a lot of hot water is used, though
it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

"Wayne Boatwright" wrote in message
5.250...
On Sat 02 Aug 2008 05:58:29a, ransley told us...

On Aug 2, 7:29 am, Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.


If you run a dishwasher you need 140°F water for optimum operation. If
you
wash white cotton fabric in the clothes washer, you need similar
temperatures. Believe it or not.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

Thats a fact jack. It never makes sense to run HW under about 140 degrees.

s


"Wayne Boatwright" wrote in message
5.250...


If you run a dishwasher you need 140°F water for optimum operation. If
you
wash white cotton fabric in the clothes washer, you need similar
temperatures. Believe it or not.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

ransley wrote:
On Aug 2, 9:10 am, Wayne Boatwright wrote:

On Sat 02 Aug 2008 05:58:29a, ransley told us...






On Aug 2, 7:29 am, Theo wrote:

Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more in summer.

If you run a dishwasher you need 140°F water for optimum operation. If you
wash white cotton fabric in the clothes washer, you need similar
temperatures. Believe it or not.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------- Hide quoted text -

- Show quoted text -


Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.

PO's of my house were like that. I immediately turned the water temp up
so I could take a comfortable shower. Plus if you don't have it at
least 130F you can get nastiness growing in the water. I think before
the hot water was about 110F and I'd take a shower with all hot water
and it'd still feel cold - and then run out halfway.

Oh, and I have a solar tank feeding the gas heater, so I'm only heating
the water from maybe 90F to 130F not 65F to 130F - before you accuse me
of being wasteful.

nate

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

Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo
Water expands when heated. Most water systems tend to be closed
(regulator, backflow check etc) and in a closed system it needs
someplace to expand so it is definitely standard practice to install an
expansion tank. Small house has nothing to do with it.

ransley wrote:

Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.

We use 25% of the world's energy because we generate 25% of the world's
economy.*

You gotta have energy to make Frappachinos.


-------------------
25.4% -- $13.8 trillion out of $54.3 trillion
http://en.wikipedia.org/wiki/List_of...y_GDP_(nominal)

The U.S. is TENTH is energy usage per capita
http://en.wikipedia.org/wiki/List_of...ion_per_capita

The United States is not the villain.

On Sat 02 Aug 2008 08:01:21a, ransley told us...

On Aug 2, 9:10*am, Wayne Boatwright wrote:
On Sat 02 Aug 2008 05:58:29a, ransley told us...





On Aug 2, 7:29*am, Theo wrote:
Recently replaced old electric water heater with a 40-gallon
SuperStor
running off oil furnace. It now overpressures and vents several times
a week. Feed pressure is about 30 PSI. A cheap max-indicating
pressure
gauge confirms that pressure jumps whenever a lot of hot water is
used
, though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water
expandi
ng from 55F to 140F is going to strain the pipes in this small house,
and that some kind of expansion tank (like the one in the heating
system, right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Dont you mean it runs off your boiler, what vents, the boiler or
heater, On my old pipes I would never let them get over 75, 150Lb ! I
think you are crazy to run it at all. The installer was a hack if it
actualy goes to 150lb. Whay do you even need 140f water, lower it now
to the lowest temp you need to take a hot water shower, with no cold
added. for me thats 95f, it will lower pressure before you break alot
of stuff. Pressure should not be more than incomming. Also you now run
the boiler to heat water in summer, likely that will cost you alot
more
in summer.

If you run a dishwasher you need 140°F water for optimum operation. * If
you wash white cotton fabric in the clothes washer, you need similar
temperatures. *Believe it or not.

--
* * * * * * *Wayne Boatwright * * * * * *
-------------------------------------------
* * *Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
* *Don't start an argument with somebody *
* *who has a microphone when you don't; *
* * they'll make you look like chopped * *
* *liver. --Harlan Ellison, on hecklers *
-------------------------------------------- Hide quoted text -

- Show quoted text -

Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.


Many or most dishwashers have a "heat assist" to help maintain water
tempeature, but will not raise the temperature to correct operating levels.
Only some (usually high end) models have heaters with enough power to heat
(or preheat) the water to the correct operating temperature. Our
dishwasher is one with "heat assist". When we first moved into this house
(it was a new house), the water heater was set much lower than 140°. The
dishwasher was doing a really lousy job. When I increased the setting on
the hot water heater, the dishwasher's performance was superb.

In a prevous house we installed a high end, all bells and whistles
dishwasher which had water pre-heat cycles. We kept the water heater set
at a reasonably low temperature. The dishwasher performed flawlessly, but
because of the water heating cycle, the total operation time for a load of
dishes was well over 2 hours. In part, it depends on where you want to
spend your energy. I'm sure it wasn't exactly cheap for the heating
element in the dishwasher to preheat each batch of water to the correcct
temperature before running that part of the cycle.

We live in AZ where the incoming water is one the warm side most of the
year. Because of this, we also do not need a large water heater, nor are
ever having to raise 35-40° incoming water to proper temperatures. Ours is
only a 30 gallon quick recovery electric tank. I doubt seriously if we are
wasting a lot of energy.

We do have gas or oil service in our area, so electric was the only choice
in town.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

On Sat 02 Aug 2008 09:17:21a, HeyBub told us...

ransley wrote:

Dont all dishwashers have electric heaters to bring the temp to what
is needed, mine does, whites, I use Bleach. No wonder this country
uses 25% of the worlds energy with only 5% of its population, nodody
cares about conservation. 140f is a waste, and if you really think
about where that hot water goes, down the drain. I keep mine around
100f in summer and my gas bill is still high.

We use 25% of the world's energy because we generate 25% of the world's
economy.*

You gotta have energy to make Frappachinos.

And where would we be without those? :-) I just gotta have my morning
"Iced Venti Americano, No Water, Extra Ice, and Half and Half".

-------------------
25.4% -- $13.8 trillion out of $54.3 trillion
http://en.wikipedia.org/wiki/List_of...y_GDP_(nominal)

The U.S. is TENTH is energy usage per capita
http://en.wikipedia.org/wiki/List_of...nsumption_per_
capita

The United States is not the villain.






--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

{snip}
I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.


I presume you DON'T have anti-pipe knocking "water hammer" arresters on
your hot water piping.

Many DIY home improvement books show you how to make your own with copper
piping. Fun DIY project for long rainy weekend. Good training for
sweating copper.

Commercial versions just for visual demo:
(click on link in write up for Water Hammer.
http://www.factsfacts.com/MyHomeRepair/PipeNoises.htm

should be available at local BORG.

Phil

In article , "Steve Barker DLT" wrote:
there should always be an expansion tank.

Not if you're on a well, in which case the pressure tank serves the same
purpose.

On Aug 2, 10:54*am, "Steve Barker DLT"
wrote:
Thats a fact jack. *It never makes sense to run HW under about 140 degrees.

s

"Wayne Boatwright" wrote in message

5.250...





If you run a dishwasher you need 140°F water for optimum operation. *If
you
wash white cotton fabric in the clothes washer, you need similar
temperatures. *Believe it or not.

--
* * * * * * Wayne Boatwright
-------------------------------------------
* * Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
* Don't start an argument with somebody
* who has a microphone when you don't;
* *they'll make you look like chopped
* liver. --Harlan Ellison, on hecklers
-------------------------------------------- Hide quoted text -

- Show quoted text -

Thaere is no purpose unless you are rich and can afford to **** it
down the drain, which is exactly where HW goes

On Aug 2, 12:46*pm, (Doug Miller) wrote:
In article , "Steve Barker DLT" wrote:

there should always be an expansion tank.

Not if you're on a well, in which case the pressure tank serves the same
purpose.

Im on city water I and no neighbors have an expansion tank on the WH,
I do on a boiler that heats the house not not the WH,

On Sat 02 Aug 2008 11:03:23a, ransley told us...

On Aug 2, 10:54*am, "Steve Barker DLT"
wrote:
Thats a fact jack. *It never makes sense to run HW under about 140 degr
ees.

s

"Wayne Boatwright" wrote in message

5.250...





If you run a dishwasher you need 140°F water for optimum operation.
*If you wash white cotton fabric in the clothes washer, you need
similar temperatures. *Believe it or not.

--
* * * * * * Wayne Boatwright
-------------------------------------------
* * Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
* Don't start an argument with somebody
* who has a microphone when you don't;
* *they'll make you look like chopped
* liver. --Harlan Ellison, on hecklers
-------------------------------------------- Hide quoted text -

- Show quoted text -

Thaere is no purpose unless you are rich and can afford to **** it
down the drain, which is exactly where HW goes


There is definitely a purpose, whether you think so or not. Obviously I
can afford to **** it down the drain whil using it as neceessary, and you
obviously cannot. So **** off!

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

On Sat, 02 Aug 2008 16:29:09 GMT, Wayne Boatwright wrote:

We live in AZ where the incoming water is one the warm side most of the
year. Because of this, we also do not need a large water heater, nor are
ever having to raise 35-40° incoming water to proper temperatures. Ours is
only a 30 gallon quick recovery electric tank. I doubt seriously if we are
wasting a lot of energy.

Here in Scottsdale, I was once able to take a shower with just the
"cold" tap water. It had heated to 110 during a brief circuit around
an outside wall.

Theo wrote:

Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

Are you on city water, with a check valve? A well pressure tank could
handle the hot water expansion, if the water heater has no check valve.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house,

Water's density at temp T (F) is about 62.46-0.01(T-68) lb/ft^3.
Copper pipes can expand a little. A larger house with more pipes
would have a smaller pressure increase.

and that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed.

If so, put it on the cold water side. Hot water may ruin it.

Nick

On Sat 02 Aug 2008 11:36:33a, AZ Nomad told us...

On Sat, 02 Aug 2008 16:29:09 GMT, Wayne Boatwright
wrote:

We live in AZ where the incoming water is one the warm side most of the
year. Because of this, we also do not need a large water heater, nor
are ever having to raise 35-40° incoming water to proper temperatures.
Ours is only a 30 gallon quick recovery electric tank. I doubt
seriously if we are wasting a lot of energy.

Here in Scottsdale, I was once able to take a shower with just the
"cold" tap water. It had heated to 110 during a brief circuit around
an outside wall.


Yes, that's sometimes possible. I remember in a previous house during the
summer, running out of hot water from the tank, and the incoming water was
nicely warm for showers.

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

WHAT WAYNE SAID! jEEEEEZE... I'm glad i filtered out that fukin pin head.

s


"Wayne Boatwright" wrote in message
5.247...


Thaere is no purpose unless you are rich and can afford to **** it
down the drain, which is exactly where HW goes


There is definitely a purpose, whether you think so or not. Obviously I
can afford to **** it down the drain whil using it as neceessary, and you
obviously cannot. So **** off!

--
Wayne Boatwright
-------------------------------------------
Saturday, 08(VIII)/02(II)/08(MMVIII)
-------------------------------------------
-------------------------------------------
Don't start an argument with somebody
who has a microphone when you don't;
they'll make you look like chopped
liver. --Harlan Ellison, on hecklers
-------------------------------------------

Theo wrote:
Recently replaced old electric water heater with a 40-gallon SuperStor
running off oil furnace. It now overpressures and vents several times a
week. Feed pressure is about 30 PSI. A cheap max-indicating pressure
gauge confirms that pressure jumps whenever a lot of hot water is used,
though it doesn't always reach the 150 PSI needed to vent.

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house, and
that some kind of expansion tank (like the one in the heating system,
right next to the SuperStor) is needed. They think I'm nuts.

Can anyone here offer relevant experience or practice?

Thx-

Theo

Well, there are already plenty of replies, but Internet bits are cheap.
I'll try to make this sound educated.

If there is an inlet supplying pressure at 30psi, the pressure rise due
to expansion of heated water will just push a tiny amount of water back
up the pipe, and the pressure will stay at 30 psi. There seem to be just
two things that might cause pressure to exceed 150psi (the setpoint of
your relief valve) -- boiling and water hammer.

Water hammer in a home system happens when a valve or faucet is closed
suddenly, causing a shock wave to travel backward through the pipe until
it hits something, like an elbow. Just possibly, if your tank is
actually filled solid with no trapped air, the pressure wave might
exceed 150psi at the relief valve, causing it to open very briefly. The
cure for this problem is an air chamber installed, usually, near the
valve. The air will allow the shock wave to dissipate into the trapped
air, eliminating it.

Far more likely is the possibility that the water is overheating, and
occasionally exceeding the boiling temperature of water (at 30psi, that
is about 250F). I don't know just how the temperature is sensed and
controlled, but that is where I would look for the problem. That or just
turn the thermostat down to 120F. That should be hot enough for normal
purposes, dishwashing included. Oh by the way, boiling in the water
heater could be very disastrous if the relief valve should stick shut,
of if the boiling is rapid enough to overwhelm the relief. There is an
impressive video somewhere on the Internet of a water heater launching
itself a good distance into the air, powered by steam.
** Posted from http://www.teranews.com **

Tony wrote:

Theo wrote:

I've tried to convince the installers that 40 gallons of water expanding
from 55F to 140F is going to strain the pipes in this small house...

With a density 62.46-0.01(T-68) lb/ft^3 at T (F), 40 gallons at 55 F weighs
62.59 pounds per ft^3, ie 62.59x40/7.48 = 334.7 pounds. Heating it to 140 F
raises the volume from 5.348 to 5.421 ft^3, an increase of 0.073 ft^3, or
0.55 gallons. In a large house with a working check valve on a city water
supply, those 2 quarts might expand the pipes elastically with no damage at
say, 60 psi, but that seems unlikely, since copper doesn't stretch much
at that pressure.

If there is an inlet supplying pressure at 30psi, the pressure rise due
to expansion of heated water will just push a tiny amount of water back
up the pipe,

"Tiny" as in 2 quarts :-) But we can't push water back through a check
valve, which is often a safety requirement with city water supplies...

This could be a non-problem if the water heater were a more elastic $60
1"x300' 13-gallon black plastic HDPE pipe coil in 140 F solar-heated water
in a 4'x8'x3' deep plywood box tank with a folded 10'x14' EPDM rubber liner.

Nick

Theo wrote:
Recently replaced old electric water heater with a 40-gallon
SuperStor running off oil furnace. It now overpressures and vents
several times a week. Feed pressure is about 30 PSI. A cheap
max-indicating pressure gauge confirms that pressure jumps whenever
a lot of hot water is used, though it doesn't always reach the 150
PSI needed to vent. I've tried to convince the installers that 40
gallons of water
expanding from 55F to 140F is going to strain the pipes in this
small house, and that some kind of expansion tank (like the one in
the heating system, right next to the SuperStor) is needed. They
think I'm nuts. Can anyone here offer relevant experience or
practice?

Thx-

Theo

Well, there are already plenty of replies, but Internet bits are
cheap. I'll try to make this sound educated.

If there is an inlet supplying pressure at 30psi, the pressure rise
due to expansion of heated water will just push a tiny amount of
water back up the pipe, and the pressure will stay at 30 psi. There
seem to be just two things that might cause pressure to exceed 150psi
(the setpoint of your relief valve) -- boiling and water hammer.

Water hammer in a home system happens when a valve or faucet is closed
suddenly, causing a shock wave to travel backward through the pipe
until it hits something, like an elbow. Just possibly, if your tank is
actually filled solid with no trapped air, the pressure wave might
exceed 150psi at the relief valve, causing it to open very briefly.
The cure for this problem is an air chamber installed, usually, near
the valve. The air will allow the shock wave to dissipate into the
trapped air, eliminating it.

Far more likely is the possibility that the water is overheating, and
occasionally exceeding the boiling temperature of water (at 30psi,
that is about 250F). I don't know just how the temperature is sensed
and controlled, but that is where I would look for the problem. That
or just turn the thermostat down to 120F. That should be hot enough
for normal purposes, dishwashing included. Oh by the way, boiling in
the water heater could be very disastrous if the relief valve should
stick shut, of if the boiling is rapid enough to overwhelm the
relief. There is an impressive video somewhere on the Internet of a
water heater launching itself a good distance into the air, powered
by steam. ** Posted from http://www.teranews.com **

Or as the next poster points our eventually, there is a check valve that
prevents water expansion from going back into the water supply system.
The expanding water has nowhere to expand to. Usually that is handled
by adding a small air tank similar to the bladder types that well users
have.
I doubt it's water hammer, though.
Yeah! I've seen that water heater video! It's impressive! Shot
right through the roof of the enclosure they build over it! Forget how
far it went, but it was impressive!

If I can't convince you I may as well join you.

Get a threading browser or get ignored.

"David Williams" wrote in message
...
- I doubt most of us want to drag trailers full of uncompressed hydrogen
- around just to get to the corner store and back. Hydrogen contains very
- little convertible energy per volume size.

You could get to the corner store and back on much less than a cubic
metre of hydrogen. Put a bag on the roof of your car. For longer
journeys, yes, a trailer would be a good idea. So... WOuld you rather
walk?

dow

In article ,
"Solar Flare" wrote:

If I can't convince you I may as well join you.

Get a threading browser or get ignored.


Hey Solar Fart, you just figured dow out? Most of the rest of us
have been ignoring him for months, now.....

I can't read your post. Must be my defective killfilter.

"You" wrote in message
...
In article ,
"Solar Flare" wrote:

If I can't convince you I may as well join you.

Get a threading browser or get ignored.


Hy Sold Fat, you judt figed dw out? ost d the rest od us
hade beedn ignding himdmonths, now.....