Copper water coils - Why not ??

JJLL wrote:Also, solder melts at roughly 300 °F. Water boils at 212°F In short, your pressure relief valves would blow before the soldering failed.

The solder won't fail if the tube is full of water. I run 375* steam through soldered joints and they don't fail. It melts at 300* the first time, it takes more to remelt it. I'm not sure how much more.
I would not recommend copper for a coil however.

Coal burns considerable hotter then wood, I'm hesitant about copper coils in a coal appliance.

I've burned lots of scrap lumber, nails and all, in my wood stoves, the nails were always there in the ash. I've also used scrap lumber to start the Harman, I have yet to find an intact nail in the ashpan. I did find the remnants of a few, they crumbled under slight pressure.

I'd stick to stainless steel.

gambler wrote:Keystoker uses copper water coils! But it looks like it is not in direct contact with the flue gas.

http://www.keystoker.com/coaloilboilers.html

That coil is immersed in the water jacket of the boiler.

50/50 solder melts at 361f-420f. Axeman Anderson uses finned copper coils immersed in the boiler water.

Yeah but that's immersed in water too.I think they call thoes fins perco or something like that.
DON

Always thought copper would be OK to use, may give it a try this winter to put some heat into the basment. Can anyone jog my memory on how gravity feed works.
Ray

See here

http://nepacrossroads.com/kb/Hot_Water_Coil

Chris

I realize this is an old thread but I'm curious about making a copper hot water coil for DHW in my hand fed coal furnace. I would be very interested in hearing your opinion on what type copper to use and what size. There seems to be mixed opinions in this thread. I would love to hear from someone that has done it

OR why not black iron pipe with a thick coat of high temp stove paint? Seems like the paint would survive since the pipe is full of water and shouldn't even get near the temp the high temp paint could handle..

$250.00 for a good Stainless steel water coil seems like alot..

Any thoughts appreciated

Well, first off, I have never tried any coil...so take this for what it is worth.

Give the copper a try, but use a thicker walled version as opposed to the thinner types.

Black iron would need to be bent into a coil, as adding many fittings inside the fire box would create many areas for possible leaks due to extreme temperature swings...expansion & contraction.

Other members here have bought stainless steel straight lengths of pipe and used a hand conduit bender to form their coils.

I would prefer a copper tank mounted as tight as possible to the side or back of the stove on the outside. Maybe 2 to 2.5 inches width by the size of the mounting area on the stove.

Thanks for the great suggestions fellas

I found this site that sells SS pipe -

http://www.onlinemetals.com/merchant.cf ... &top_cat=0

Less than $25.00 for a 5 foot section of 3/4 inch!
Would this pipe be good for a DHW coil?

The problem with copper and especially soldered joints in the firebox isn't that they will melt or corrode if everything is working properly and you have proper flow and cooling capacity, the problem is that IF something doesn't work right, if the circulation fails or your water temp through the coil gets too high or the pressure is removed from the domestic water system, then you will have a rapid failure with serious consequences. Stainless will maintain its strength and integrity well over twice the temperature copper will, and many times that of a soldered joint; if there is a problem, with stainless (or even other steels), and a steam bubble forms, the rapid heating that will occur won't lead to a catastrophic and potentially deadly failure of the system.

My neighbor had a system like Big Beam's with similar results. 6 kids (4 females) and never ran out of hot water. Wood also though.

Given my terrible experience with Hilkoil's CRAP customer service, if my stainless coils were to fail again I wouldn't hesitate to replace them with copper. Would end up a tenth of what I paid those jerks in NY. Being that my setup is tied into the boiler, any catastrophic failure of my system would be prevented by the safety devices already on the boiler.

Just got to remember to OPEN THE VALVES!! I've forgotten that once. The severe water hammer gets your attention REAL quick!

I'm wondering why you would want to use copper in the firebox.
If you had a panel mounted on the outside of the stove i would think it to be safe and reliable.

In the firebox is going to produce a million times the amount of heat you'd get from the outside. Less trouble outside, but less heat output also. I'd throw them in there & just deal with the issues as they come.

One thing is for certain - whether you have a basement like mine (swamp) or not, they would HAVE to come out every spring. If you left them in there covered in flyash, I don't think there would be anything left to clean in the fall!