Thermosiphon Question for Coil

efo141 wrote:Is there a way of using the aquastat in my elect. water heater to control a bronze pump? So instead of the elect elements it would control a pump that would cicul. water through my coal boiler coil

Can anyone answer this question?

You're going to want water circulating through the coils at all times. If not the water will boil in the coil and open up the PRV. You're better off putting in a mixing valve to assure that no one gets scalded.

I will have a Keystoker kaa2 boiler. I dont think the water in the coil should be any hotter than the water in the boiler. I think they have a seperate aquastat for a over heat dump zone that will be hooked to a hanging heater or my hot water heater. I wanted to know if i could wire the aquastat in the water heater to a pump and circul the water through the water heater from the coil on the Keystoker using the PRV and the drain valve. Any info would be great Thanks
Ed

traderfjp wrote:You're going to want water circulating through the coils at all times. If not the water will boil in the coil and open up the PRV. You're better off putting in a mixing valve to assure that no one gets scalded.

If the coil is in a home heating appliance running at below the boiling point of the pressure in the system -- how would the water in the coil boil at city water pressure

efo141 wrote:

efo141 wrote:Is there a way of using the aquastat in my elect. water heater to control a bronze pump? So instead of the elect elements it would control a pump that would cicul. water through my coal boiler coil

Can anyone answer this question?

sure!

Clamp on a surface contact Honeywell control to the output of you current domestic hot water heater - wire it to close on temperature drop and open when it reaches 125 degrees - code set for domestic hot water out. then you won't need an anti scald valve and you won't need to change the PRV and the heater will run as it always did if you don't burn coal in the off season.

Pictures??? I posted some someplace of this! PM me if you want a copy! pump from the boiler coil into the bottom of the hot water heater and from the top (port out) of the tank back to the boiler DHW leg and thats your loop.


Check back to page one of this thread -- its already there!

I read it wrong. I thought he was running the water through coils in a coal stove and then into a water heater. My mistake.

The first pic is the correct way to do it.Keep in mind that most tankless coils have a flow restrictor built into them.This should be drilled out as large as posible for flow reasons.Do a search for range boilers and you will see how it was done years ago off of a kitchen stove.I built one years ago in a wood stove and piped it up like the first pic.Worked like a charm.I don't know how big your HW tank is but I would install a gate valve in the loop.The coil I made would heat up a 30 gal.uninsulated tank in about 1 hr. With a insulated tank you WILL have to slow it down a little.
DON

BTW keep the feed line to the relief valve slanting up slightly and the return line from the boiler drain slanting slightly up to the coil.You may be able to keep the gate valve open full bacause of the standby loss in an oil fired water heater.If you run the boiler at 180F the tank will also get that hot so a mixing valve will be needed to drop that.I didn't use a mixing valve in my system,you can mix at the faucet.

One more thing I forgot.You will need unions on the coil as close as posible to the boiler.When you refill the water heater you will need to crack the union that feeds hot water to the top of the tank to purge any air that is in the coil.there will be no presure there because you will open a hot water faucet when filling the tank to let the air out as it fills.crack the union when the tank is about 3/4 full
IF YOU DON'T GET ALL THE AIR OUT OF THE COIL IT WILL NOT SIPHON.
DON

Pumping eliminates all that drama!

Thermosiphon= no maintainance, no electric
maybe acid out the coil every 10 or 20 years!
DON

Hello
A while back I hooked a auxilary tank to my electric hot tank. The aux tank relied on thermo and was plumbed so tank bottom was about a foot off floor. Blowoff valve was on side hotwater entered top at a "T"on top. Street water water pushed "stove heated water" into electric tank giving me double storage . Being my exchanger was mounted outside of stove I never had blowoff work .
Water got to abround 150 so I used to crack open a faucet to keep it circulating thru both tanks.
The one thing I did discover is dont start with a used watertank like i did.....It only lasted a few weeks and sprang a big leak.
I now have a exchanger made from baseboard ready to mount on my new furnace It will also be external. I dont need fast recovery because of the added storage using 2 tanks.
There is a lot of info on a site called "Field lines" or "Other power " dot com with wind solar and water etc.
Word of warning some on this site dont take kindly to coal burning....they think coal is still in the dark ages..Coal helped make this a great nation.