We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Thanks for any help.

R

you haven't said where the heaters are. if they're next to each other, it's
pretty easy to make some sort of manifold to connect them. if not, you may
have to repipe and tear into quite a few walls to do this.

"Rick" wrote in message
ups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Thanks for any help.

R

"Rick" wrote in message
ups.com...
The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub?

Can be done, but may not be the best idea. Why keep 40 gallons of water hot
for days on end if it is not being used? Consider one of the point of use
heaters that works only on demand.

At least talk to someone that knows about them. If you use the tub daily,
that is one scenario, but if it is a once a week treat, it may pay to go the
instant route.

"Rick" wrote in message
ups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Thanks for any help.

R


Crazy non standard solution would be to plumb a separate hot pipe from the
upstairs tank to the tub downstairs with its own separate faucet (i.e. no
cross connection) You will have the benefit of filling the tub twice as
fast. Pipe the cold for that faucet from anywhere convenient. Nothing in
code I am aware of prohibiting multiple taps in a tub.

Try diagramming the plumbing in your house, this will help you communicate
options to others for advice. Scan and post the diagram on a website and
post a link here. Cross connecting the two hot systems could cause problems
if there is a pressure differential anywhere, you could have water flowing
in an unintended direction. Depends on where/how you do it.

According to PipeDown :

"Rick" wrote in message
ups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Crazy non standard solution would be to plumb a separate hot pipe from the
upstairs tank to the tub downstairs with its own separate faucet (i.e. no
cross connection) You will have the benefit of filling the tub twice as
fast. Pipe the cold for that faucet from anywhere convenient. Nothing in
code I am aware of prohibiting multiple taps in a tub.

This is not a bad idea at all. Filling large tubs take quite
a while, so you get the added advantage of halving the time.

Another approach, assuming they're relatively adjacent, is to
"plumb them in series", and move all your hot plumbing to the
"downstream" tank, so all hot water has to go through both.

Instead you could plumb a line from the output of the tank _not_
feeding the tub into the input to the other tank. Both are in
series for the tub, and only the first tank is used for other things.

The latter two don't fill the tub any faster, but will provide
enough hot water. It's perfectly okay to feed hot water _into_
the input of a HWT.

From the perspective of cost of operation, an "idle" electric HWT consumes
about $3 worth of power a month just to maintain temperature. Short
of bypassing/decommissioning one of the HWTs, that will be your approximate
incremental cost of operating both.

Try diagramming the plumbing in your house, this will help you communicate
options to others for advice. Scan and post the diagram on a website and
post a link here. Cross connecting the two hot systems could cause problems
if there is a pressure differential anywhere, you could have water flowing
in an unintended direction. Depends on where/how you do it.

Cross-connecting - meaning, hooking them in parallel. Depending on how
your plumbing works, it would likely mean that one of the HWTs is effectively
useless.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

"Rick" wrote in message
ups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Thanks for any help.

R

Your spa tub must be huge. I have one that once I made a slight adjustment
with the temp setting my 30 gallon water heater does the trick.

I would try raising the set point before I played plumber, but that just me.

Crazy non standard solution would be to plumb a separate hot pipe from the
upstairs tank to the tub downstairs with its own separate faucet (i.e. no
cross connection) You will have the benefit of filling the tub twice as
fast. Pipe the cold for that faucet from anywhere convenient. Nothing in
code I am aware of prohibiting multiple taps in a tub.

This is not a bad idea at all. Filling large tubs take quite
a while, so you get the added advantage of halving the time.

Maybe. In my house, the limiting factor is how fast
I can get water out of the pressure tank, so having
pipes from two separate water heaters would just get
me anemic flow at both taps.

"Rick" wrote in message
ups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters

Why do you want to heat hot water?

On Wed, 14 Dec 2005 15:29:39 -0700, "SQLit" wrote:


"Rick" wrote in message
oups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters in the attic; one serving
downstairs, and one sserving upstairs. The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub? Would like self-perform the
work, and I am pretty handy. Just don't want to screw something up,
since I am not really that familiar with plumbing. All plumbing piping
in the house is poly.

Thanks for any help.

R

Your spa tub must be huge. I have one that once I made a slight adjustment
with the temp setting my 30 gallon water heater does the trick.

I would try raising the set point before I played plumber, but that just me.

I agree. I have a 52 gallon tank, and a smaller than what I grew up
with bath tub, and It takes me almost the full water heater to fill
the tub. I know, because if I fill it to the top and it's either too
hot or too cold, and I drain some out, there's often not enough hot
water to fill it up again.

I used a measured bucket and ladled the water out of the tub and it
was about 100 gallons, so I'm using about 50% hot water and 50% cold.

I'm a little slow witted, but someone else pointed out to me the
solution, to make the hot water hotter. I haven't done this, but I'm
the only one hear and I can plan my water use without surprises.

How did the previous owners handle this?


Remove NOPSAM to email me. Please let
me know if you have posted also.

"Edwin Pawlowski" wrote in message news:OM%nf.2190$1b.1909@trndny03...

"Rick" wrote in message
ups.com...
The only time the upstairs is
used is when we have guests, which in not often. We have a large
whirlpool tub that my wife likes to use, but the 40 gal heater is
barely enough to get water above the jets. How difficult would it be
to connect the two heaters together to be able to take advantage of the
extra capacity just for use of the tub?

Can be done, but may not be the best idea. Why keep 40 gallons of water hot
for days on end if it is not being used? Consider one of the point of use
heaters that works only on demand.

At least talk to someone that knows about them. If you use the tub daily,
that is one scenario, but if it is a once a week treat, it may pay to go the
instant route.

Actually, I was thinking that what he wants to do is the best choice. Plumb the
heaters in series, then add a way to turn the first one off/on. You can use the
other one normally, and power up the first one when you will be using the tub
a few hours later, or when you are expecting a bunch of guests. Then, you can
add (since they're in the attic) some solar collectors to the first one at a later date
to pre-heat the water.

Bob

Your spa tub must be huge. I have one that once I made a slight adjustment
with the temp setting my 30 gallon water heater does the trick.

I would try raising the set point before I played plumber, but that just
me.

I agree. I have a 52 gallon tank, and a smaller than what I grew up
with bath tub, and It takes me almost the full water heater to fill
the tub. I know, because if I fill it to the top and it's either too
hot or too cold, and I drain some out, there's often not enough hot
water to fill it up again.


I can squeeze enough extra from my 40 gal tank by running the hot water long
enough to get it to the tap then waiting for the tank to finish reheating
before actually filling the tub (10-20 minutes). I get a warm volume of
water right away from the pipe (it is insulated most of the way) and warmer
than normal water (since it just finished burning rather than sitting for a
while) from the tank. This gets me just enough to fill the tub (~70 gal).

I do have two fill taps (one shower head and one spigot) but they are fed
from the same tank. It does speed up filling somewhat but since they share
the same 3/4" pipe, turning one on does reduce the other but not by all that
much.

Bob wrote:
....

Actually, I was thinking that what he wants to do is the best choice.
Plumb the heaters in series, then add a way to turn the first one
off/on. You can use the
other one normally, and power up the first one when you will be using
the tub
a few hours later, or when you are expecting a bunch of guests. Then,
you can
add (since they're in the attic) some solar collectors to the first
one at a later date to pre-heat the water.

Bob

Sam thought I had.


--
Joseph Meehan

Dia duit

Get one Rinnai or Takagi gas tankless you will never run out of HW and
thay are more efficient

They are next to each other in the attic, so no problem getting to
them.

Do not want to go to the expense of a point of use heater at the
moment, but a good wuggestion for the long term.

I like the idea of plumbing them in series, if I understand it
correctly. The cold water input would go to one tank, and the output
of that tank would go to the second tank. Hot water to the fixtures
would come from the second tank. Is this correct? So you are dumping
cold water into one tank, and pre-heated water into the second. I will
make a diagram and study it.
Thanks to all for your input.

According to Rick :
I like the idea of plumbing them in series, if I understand it
correctly. The cold water input would go to one tank, and the output
of that tank would go to the second tank. Hot water to the fixtures
would come from the second tank. Is this correct?

Yes.

The second tank is pretty much only maintaining the temperature.

Some homes do this if there's a _long_ hot run - install a small
2-5 gallon heater at the far end in series with the long run.
It's almost "instant hot water", and doesn't suffer from low flow
rates from all but the more high capacity tankless heaters..

So you are dumping
cold water into one tank, and pre-heated water into the second. I will
make a diagram and study it.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

On Wed, 14 Dec 2005 23:43:16 GMT, "Oscar_Lives"
wrote:


"Rick" wrote in message
oups.com...
We recently moved into a new 3200 sf home, and there are only two of
us. We have two 40 gal hot water heaters

Why do you want to heat hot water?


It costs less than heating cold water.

FWIW, the Journal of Light Construction had an article about the
proper way to connect two water heaters. It was in the october 2004
issue and was titled: "Kitchen & Bath: Adding a Second Water Heater "

View it at www.jlconline.com

I think it's free, but there may be a small charge to view it.

This is a great magazine, by the way.


HTH,

Paul Franklin