On Dec 23, 2:08*pm, "Bob F" wrote:
"Steve" wrote in message

...





Ok guys, pick this one apart..... *I have a wood stove in my
basement. *I just replaced my old 52 gal electric hot water tank with
a new 40 gal model. *I am planning to use my old stripped down tank as
a tempering tank ahead of my new heater and place it as close to my
wood stove as possible (about 6 inches or so away). *I plan to remove
the upper and lower elements on the old tank and replace them with a
1" copper line from the top element threaded opening to the bottom
threaded opening and extend the copper line over my wood stove so that
it will pick up heat from the stove / flue pipe. *I am thinking cool
water from the bottom will naturally be drawn up the copper line as it
is being heated by the wood stove and will circulate back to the top
and will constantly be looping around to warm the water inside the
tempering tank. *I am thinking that possibly overnight, the water in
the tank will eventually warm up to around 100 degrees F. And the new
electric heater will only need to heat that water up to 120 degrees
F. *There are only two people in the house and no automatic
dishwasher, warm water usage for the wash cycle only of the clothes
washer @ 2 loads per week, and maybe two short showers per day. *Do
you think this is a feasable plan? *I am not any kind of engineer, but
just a practical tinkerer trying to save a few bucks on my electrical
bill......... *Thanks for any comments on this!
Steve

A few wraps of soft copper around the bottom of the exhaust stack pipe would
pick up a lot more heat. Or, a loop around the stove, or a coil right on top[ of
the stove. Of course, the copper needs to be sloped so that the heated water
rises to the top of the tank for good flow.

This is pretty much what I was planning to do. I am wondering if 1"
diameter copper is too big? Or would 1/2" diameter be better? Or
does it matter?


Don't overdo heat pickup at the stack. If you cool the stack too much, you will
get excessive creosote build up in the stack.

I don't think, but not sure, this will be that much of a concern as
the copper tubing will not actually be contacting the stack. I
normally keep a good hot fire going with well above creosote making
temp (I use a magnetic stack flue temp guage) unless I'm letting the
fire go out and then it would be just hot coals and embers burning
out.


If you are picking up a lot of heat, the tank insulation might be left on to get
truely hot water, or without insulation, the tank could operated as a heat
buffer, continuing to release heat after fire goes out.

That's more than I could hope for.......


If you want the old tank to last, check/replace the anode.

I just got done scraping and cleaning the old anode. It was in quite
good condition. Nothing was eaten away from it at all. After 30
years I've only took it out and cleaned it once. The last time was
well over ten years ago. We are lucky to have fairly mineral free
water, probably why the old heater lasted so long. I also just
flushed out the bottom of the tank and the crud level was still below
the drain outlet of the tank. We do have a whole house water filter
and water softener.

Thanks again!
Steve