Hot Water Coils

I am new to heating with coal. I used an old wood/coal stove that was in the house when I bought it to heat last winter. This spring I purchased a new Harman Mark I. I am interested in using a hot water coil to heat water this winter but am hesitant to drill holes in a brand new stove that has a 3 year warranty.

I've been to the hilkoil website and done some background research on their coil products. It seems like a good way to go - basically free hot water but any comments, suggestions or ideas that any one has would be helpful especially if you are using a coil to heat your hot water.

Thanks,
wbg

It's unfinished however there is article here describing a thermal siphon loop: https://coalpail.com/coal-heating-encyclopedia/do ... water-coil

If you use the design in that link, make sure to use "swing check", check valves, not "ball check" or "flow check". Also put a relief valve near the coil near the top.
I think he has one line of thought incorrect.... it does not work because heated water expands, it works because heat rises.
I used to have a hand built coil in a wood stove back in the 70's. It heated water in a tank and water from that tank went to my electric water heater. It knocked the crud out of my electric bill.

What do the coal coils do with too much heat? I had to make my coil smaller because it would boil the water.

Density of heated water is less than cold water so it wants to be on top. So yes, hot water does expand ever so slightly until it becomes steam and then you do notice the expansion! Water also expands when it goes solid, less dense so it floats. Most liquid to solid changes get denser, so water is a odd duck!
You need a heat sink, aka heat dump, that can dispose of the extra heat. A large 1000 gallon water tank would do, a Modine or extra baseboard radiator.

I just bought a Liesure Line Pioneer and am thinking about a hot water coil. I have oil fired baseboard hotwater now and was thinking about plumbing it so it ran through the boiler then to the hot water tank. Anyone try this?

Harman doesn't offer a coil that fits the MK1, only the MK II and III. Make sure before you drill that there is enough room to get the coil in and still service the fire. I installed one in a TLC2000 last fall and placed it too close to the fire brick and had to cut them down a tiny bit. We piped it into a 40 gal electric hot water tank by taping into the bottom drain and returning to the outlet side at the top, no check valves. The tank sits about 4 feet away from the stove and made hot water all winter. By all means make sure there is a pressure relief valve piped outside or to a drain, heating water is dangerous. Attached is the Harman manual showing a couple of hookups, look at page 9 and 10.

I put a coil in my Mark III last year and couldn't use all the hot water that was made. Ended up piping it into a toe kick heater in my kitchen where the fan turns on at 140. That way the high temp valve on the top of the water tank stopped opening up.
Tom

diagrams for hooking up domestic hot water coil from coil manufacturer two options.check out meyermfg.com/domesticcoil-install.listed at leisureline stove website with link to meyer mfg.Thanks, Jerry and staff also coil install could be cut in stove with hole saw for steel

Freddy wrote:If you use the design in that link, make sure to use "swing check", check valves, not "ball check" or "flow check". Also put a relief valve near the coil near the top.

Freddy you could add that info, that's the purpose of the KB.

Using the thermal siphon Loop method of heating your domestic water - If you are not using all the hot water you create can you tie a modine in with this method to vent off the extra heat or do you need to use the circulator pump method?

The Modine would have to be at the highest point in the loop and fairly close. The Modine has its own fan and thermostat to kick on the fan but it will probably short cycle due to the lack of a circulator. It would be best to use the circulator to bleed off the extra Btu's.

How would the circulator start and stop? A thermostat of its own or should it always be running?

Thermostat on the tank, high temp dump circuit circulator on @195* off @180*. This will bleed off the extra heat before the PRV goes off usually at 210*.

CapeCoaler,
Wouldn't the thermostat on the water heater work the opposite of what you want? When the thermostat sees 195 degrees it would actually shut power off rather than turn it on. Unless there is something that I don't understand about how they work.
Tom

The Harman diagram shows the coil plumbed into the water heater at the drain on the bottom and the pressure relief at the top. Would I be able to use this same setup on my oil boiler (using the boiler's drain and pressure relief)? It is costing me 100 dollars a month just to run my boiler for my hot water needs. It would be nice to keep the boiler hot using a coil on my stove instead of using gold......er, oil.