Hot Water Coil Project

This year, I'm putting the screws to the electric company. I'm installing two 24 inch stainless steel water coils in my Clayton 1537G. One coil will heat my DHW with a 40 gallon tempering tank (thermo siphon) in series with my 50 gallon electric hot water tank. The other coil will keep my outside hot tub heated with an independent thermostat and circulation pump. I expect this to cut my electric bill at least $100 per month for 6 months. I wanted to start a thread to document my progress. I installed the coils so far

Nice work!

Not to rain on your parade .... but ... I just hope you didn't buy those from Hilkoil. When they corrode away to nothing your "lifetime" warranty will suddenly become a "50%" warranty, and you'll be called a liar to boot. Not a very ethical operation they're running over there.

Regardless, make sure you remove, clean, and oil them at the end of the season. That will completely avoid the debacle that I endured.

Thanks Smitty!! In my efforts to research the subject, I ran across your posts about the HilKoil problem. I bought these coils from someone on Ebay. Actually, I think he makes them. I got both of them for $255 including shipping, which was the best price I could find.

I'll definately take care of them My plan is to leave them in the furnace since they were quite challenging to install with the air jacket in the equation. I'm going to have on/off valves in place so I can bypass and drain the tempering tank and coils in the summer so they aren't full of cold water (which would promote condensation). And I'll coat them with something, along with keeping a 100 watt light bulb in the firebox... Hopefully, thats enough to keep them in good condition

Fun project!

Lightning wrote: I'm going to have on/off valves in place

If the on-off valves segregate the coils, make darn sure each one has a blow off valve. If by chance the coil was closed off with no relief valve and some future user lit the fire....ka-boom!

Freddy, your absolutely correct!! I'm thinking a pressure relief valve right near the bottom of the temper tank outlet. This would put it inside the loop that would be between the bypass valves And I could also drain the coil and temper tank thru it too

My opinion, NO VALVES, you never want to risk tapping water/steam, even with relief valves.
With a hot fire and no water in the coils I'm concerend they might deform.
I had a cast water side in the stove I used to heat this place, and when we only had water seasonally we removed it, and that was with a cast heat exchanger area.

Short Bus wrote:My opinion, NO VALVES, you never want to risk tapping water/steam, even with relief valves.
With a hot fire and no water in the coils I'm concerend they might deform.
I had a cast water side in the stove I used to heat this place, and when we only had water seasonally we removed it, and that was with a cast heat exchanger area.

I wouldn't run the furnace without water in the coils The valves would be in place so I could drain the temper tank and the coil during the OFF season

Well, been busy with the hot water project I got the temper tank plumbed to the hot water coil and got it tied into the house plumbing. All I gotta do now is fire it up!! I hope It ain't pretty but it only needs to work, right??

In the picture of the 3 valves, the bottom valve blocks flow thru. The upper two valves are routed to and from the temper tank. IN summer mode when the furace ISN"T fired I can close the two upper valves and open the flow thru valve. With this situation, I can drain the temper tank and water coil with the valves over by the temper tank and run the electric tank for hot water.. In winter mode when the furnace is fired, I close the flow thru valve on the bottom and open the upper valves to and from the temper tank. This routes the cold water to the temper tank and the preheated water back.. Thats the plan anyways lol....
..
On the temper tank, you will see a drain valve on the bottom and my pressure temp relief valve pointing downward on the return from the coil. I mounted it downward to prevent an unnecessary blow offs from the relief valve. Thats my thinking anyways lol...

I do have one tiny leak.. Its on the bottom of the coil where I mounted the copper with teflon tape. I re did this joint once and slowed it down. I feel I tightened it pretty good, I don't wanna tighten it further. Its dripping at a rate of 1 drop every 5 seconds at 60 psi. I'm gonna give it a few days under pressure to see if it stops on it's own. I've seen them stop on their own in the past. I think its because if the leak is small enough, minerals will clog it up like plateletts clog a bleeding wound. But time will tell on that.. Any suggestions?

I fixed the leak finally. Its a pain to drain and heat pipes back up!! I replaced the female adapter over the stainless and wrapped more teflon tape and tightened it even harder. All set to heat water now! Just need some cold weather to fire it up

I have leaks every damn season because of my custom elbow I made, which required sawing the ends off a 90° elbow & soldering the mess together. Well, whenever I bolt the coils back together every fall, they end up in a different position which stresses the joints ... and they leak. Then I take it off, heat it up, reset it, then it ends up not lining up. It's a pain in the ass but lucky for me this should be the last season I have to deal with this bullshit (got a stoker boiler to hook up). I'll probably sell the coils at that point.

I gave up fussing with them this year, and they sealed themselves after a 260° boiler water night .... but now the boiler itself is leaking. Probably cracked it from all the 300°- to - 130° temp swings using those coils, no doubt ... Always something around here!

Oh wow, yeah I see your dilemma with that I don't know what the problem was with that female adapter joint at the bottom side of the coil. I tried at least 3 times heating the pipes, taking it all apart, redoing teflon tape, soldering it all back together. The toughest part is getting all the water out of the system first or you can't solder nothin!! I eventually replaced that female adapter and its water tight now thank God.. I was ready to chuck the whole mess out of the basement lol, but its usually at that point when the progress is made

Now that its done and water tight I'll leave it alone. I'll drain it with the valve system I have in place and not disconnect anything. In the off season I'll clean the coils good and coat them and keep a light bulb in the fire box.

Oh believe me - been there what seems like a million times with this project.

If the copper isn't 100% CLEAN, spot free, and dry ... AND doesn't have the right amount ... or contaminated flux, it'll never seal. I went through hell at the beginning of this one. Everything I soldered leaked. Turned out to be the crap flux I bought 10 years prior. Bought some new flux & I was back in business. That one threw me for a bit ....

SMITTY wrote:Oh believe me - been there what seems like a million times with this project.

If the copper isn't 100% CLEAN, spot free, and dry ... AND doesn't have the right amount ... or contaminated flux, it'll never seal. I went through hell at the beginning of this one. Everything I soldered leaked. Turned out to be the crap flux I bought 10 years prior. Bought some new flux & I was back in business. That one threw me for a bit ....

Yeah man! Its amazing how nicely they solder up when everything is just right though. Clean new copper, fux and solder.. I use steel wool to shine the copper, then flux it, heat it and that silver solder gets sucked right into the joint. But second time around after everything had water in it? Oh man, not fun... Might as well chuck what ya loosened and start over sometimes

Lightning wrote:The toughest part is getting all the water out of the system first or you can't solder nothin!!

Know that well from so many times. There's an old plumber's trick: wad up regular white Wonder Bread and stuff it in the pipe to block the water just long enough to solder your joint Then you have to let the water pressure rinse it all out somehow. Also seen gelatin capsule-like little plugs for the same purpose. They dissolve quickly and rinse out too.

Great work Lightning!

I saw an old Sears 1940's DHW coal boiler on Ebay recently, was so tempted but it was local pick up only I think, far away. Really tempting to try and get a coal fired baseboard heat system going here.

Thanks Dann! Yeah man, that bread trick sounds good. Ironically, I'm a bread salesman, maybe I should display a few loaves in some hardware stores hahaha Here have a sandwich while yer soldering pipes, oh by the way it works for a water stop if ya need to redo something!

Sorry, got a little silly there

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