Custom Made Coil Need Advice

The pipes go outside the stove. I'll look for the solder you suggested. Any ides what temps the water would see coming out of the coil with a good size coal fire?

Thanks in advance

Yanche wrote:You should use tin/antimony (95/5) solder. It's lead free as required by most plumbing codes and has a melting temperature of 455 deg F.

Believe it or not- lead free solder has lead in it, oddly enough (maybe they should call it "low lead"). It is a very small amount to be sure, but it is in there. I think it has something to do with making the stuff actually usable, because it won't stick without it.

The water temp coming out of the stove will probably not be more than 220-240* if it is higher than that, then you will be blowing off the PRV all the time.

As for leaded solder, unless you have a new home, built in the last decade or so, we are drinking from water pipe systems that have leaded solder in the joints. I know for a fact that ALL the homes I've lived in used leaded solder, since my father and myself were who installed the plumbing. No PVC except for waste plumbing.


The new 'low lead' solder works pretty good, expecially when using the 'self tinning' flux. That flux works amazingly well. It's what I use now, mainly because that's all that is available.

greg L

I'm still waiting on my coil. I'll have about 40 feet of surface area in the stove. That should make some decent hot water. The more I think about the design the more I'm inclined to put in a storage tank to keep 30 gallons of hot water ready to run through my heating system. It's nice to know I can use regular solder since using copper will make the plumbing much quicker then trying to use threaded pipe which is a nightmare if you get leaks.

Hi,

I finally received my 316 .065 S.S. coil. I was hoping I could clarify a few things. The coil is about 20" long and about 8" wide. It fits nicely in the upper section of my Alaska stove. The two threaded nipples off the ends of the coil will come out the side of the stove. I don't think that the female connections that will screw onto the ends of the coil will be enough support to hold up the coil. I was thinking of using a threaded rod and screwing it in from side to side and using it to support the underside of the coil. Any thoughts on this of better idea. Unfortuately I don't own a welder??

Also, this coil will be used for hotwater baseboard heat and not domestic. I want to run the water through the coil, a holding tank and then into the boiler. Can I use the drain and releif valve outlet on my boiler for an in/out to circulate the water?

Also, I'm still wondering if I'm better off using galvanized pipe off the stove and then run copper from there. I'm just a little nervous about using copper directly off the coil and having a solder joint that is right up against the side wall of the stove? Any comments?

Also, am I better off with a 30, 40 or a 50 gallon tempering tank? The coil is about 40' of SS pipe coiled so it should put out some decent heat. I'm trying to heat my basement and to take the chill out of the 2nd floor. Worst case scenario is that I'll produce enough heat to do the basement and take most of the load off the boiler. Thanks in advance

traderfjp wrote:The two threaded nipples off the ends of the coil will come out the side of the stove. I don't think that the female connections that will screw onto the ends of the coil will be enough support to hold up the coil. I was thinking of using a threaded rod and screwing it in from side to side and using it to support the underside of the coil. Any thoughts on this of better idea. Unfortuately I don't own a welder??

Can I use the drain and releif valve outlet on my boiler for an in/out to circulate the water?

Also, I'm still wondering if I'm better off using galvanized pipe off the stove and then run copper from there.

Also, am I better off with a 30, 40 or a 50 gallon tempering tank?

A bulkhead fitting where it goes through the stove wall. I would bend a strap iron support in an upside down U and place it in the front. It can sit on the firebrick, I would not weld on the unit if you don't have to.

You can use the outlet for the PRV with a TEE, not ideal but it works.

No galvinized anywhere. Copper only.

Bigger is better.

You wrote: A bulkhead fitting where it goes through the stove wall. So I guess I shouldn't worry about soldering my L copper into the bulkhead? There is no chance of a solder joint failing from the heat of the stove?

Your wrote: I would bend a strap iron support in an upside down U and place it in the front. It can sit on the firebrick, I would not weld on the unit if you don't have to.

I don't have a welder so that is not an option. I also have a stoker so there is no firebrick just an ash pan and grate so the upside you joint wouldn't work. I was thinking of getting a 3" wide piece of steel and running under neath the coil and then screwing on l brackets to the ends and then srewing this into the sides of the stove. It would keep the direct heat off the coil, help keep some of the fly ash off the coil and support the weight of the coil. I could go with a 1" wide pice of steel of even make an air gap and try to seal the coil from the fire completely. I have one shot at this so... Any thoughts??



You can use the outlet for the PRV with a TEE, not ideal but it works.

I doubt the solder could fail when full of water in any case. Solder will hold up to 375* @ 115# steam very well.
Any way you can keep it out of the fire, coil and support (a couple of inches minimum). Find a lip, door bulkhead, anything that's away from the burning coal. Anything in the fire will go bye-bye quick.

Don't sheild the coil, you will lose heat input.

I think a piece of threaded rod with a sleeve over the threads will support the coil just fine. I'd use a piece of 3/8" or 1/2" 'all thread' [it's cheap] and slip it inside a piece of 1/2" or 3/4" pipe. the pipe will provide more stiffness, and will protect the coil from the sharp threads of the 'all thread'.

I don't think you need a big bracket, and I wouldn't use one that will act as a shelf to collect fly ash.

As for the PRV, just make sure that you have it at the high point of the water loop, this way it is self purging [removes steam bubbles] and make sure you have water pressure supplied to the loop through a pressure reducer valve to provide make-up water if the PRV opens.

I can't remember, are you going to isolate the baseboard loop for the basement from the rest of the hot water system?? if not, then the boiler's water mass will absorb a lot of heat, you may not need the storage tank. Just a thought.

Greg L

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I'm not sure what a door bulkhead is?? The bulkhead (adapter) will be outside the stove but right up against the side of the stove. Why are you against galvanized pipe?? So you think I'll be OK with a simple copper female to slip joint adapter?

Ls: The pipe over the threaded pipe is a great idea. However, I hate to cut another 2 holes into my stove. Another option is to use galvanized band iron and attach it to the back of the coil and to the top of the stove. I'll still have to cut a hole but it will not be seen because of the extra cast iron lid that comes with my stove. I could even get a U bolt or something. What do you think?

You wrote: I can't remember, are you going to isolate the baseboard loop for the basement from the rest of the hot water system?? if not, then the boiler's water mass will absorb a lot of heat, you may not need the storage tank. Just a thought.

I was told by utica that there is only about 10 gallons of water in the boiler and I have no idea the amount of water in the actual pipes that make up my heating system (baseboard heat, piping, etc.). I was worried that without the tempering tank the 40' coil would only be circulating 10 gallons of water and blowing off the PRV when temps were more mild and there wasn't a huge need for heat. My thinking is that the tempering tank will keep 30-50 gallons of water (haven't decided on the right size of tank) hot and this will help to bleed the heat coming off the coil. When the house needs heat the water from the tempering tank would circulate through the boiler and into the heating system and to the baseboard heat. If I needed more heat the retention heat would kick on. To complicate things more I also wanted to use the coils inside my boiler to feed my hot water heater and once again if the coils can't keep up the oil retention head would kick on and take up the slack. I'm still not sure if 30 gallons of 50 gallons is the right number for the tempering tank? Also, the boiler has a pressure feed valve on it so if the PRV blows the boiler feed valve will turn on so I think I'm covered there. I also wanted to add another pressure relief valve right at the coil too. I may even need a UPC backup for the Taco circulato incase the power goes out for 10-15 minutes. Any thoughts. I hope I'm not complicating this too much but I want to do this right the first time. When I'm done I'll create a document to help others. With oil at 2.50 a gallon I think more homeowners willbe looking towards coal. Thanks again[/i]

A bulkead fitting is just the threaded fitting that has a jamb-nut on each side of the steel wall you are mounting the coil in.

Galvanized pipe is usually not great quality, the glavanizing ads yet another dissimilar metal to the system which with the water can cause galvanic action [corrosion] there is nothing wrong with all copper. It is the best in my opinion. [take that for what it's worth ]

For the support, I was thinking of only drilling two holes for the all thread, keep the pipe inside. So two 38" or 1/2" holes should not be a big deal, if you don't use them later, just put a bolt and nut in the hole.

As for the boiler's mass, well 10 gallons isn't much, so I guess a bigger tanks is in order. Is the basement a living space, like a bedroom? Or is it an 'occasional use' space?? The reason I ask is if you need to 'dump' excess heat, then just circulate the water in the basement baseboard loop, and let the rooms get toasty warm.

Baseboard needs fairly hot water to be effective, in my house, I can get away with 140-150* water untill the outside temps drop to the teens, then I need to have hotter water in the baseboards. Most gas or oil boilers are rated at 180-200* water. The hotter the water in the baseboard the more BTU's it can tranfer to the fins and air.

What I'm getting at is if your coil in the stove isn't able to create water hotter that 140* or so, then your augmented heat to the baseboards won't be very effective. However, a constantly circulating 110-120* is still going to create a lot of warmth.

I think you may want to plumb this system with a small storage tank, maybe use a used electric hot water heater tank, [usually free]. Just include shut off valves at strategic locations so you can bypass the tank [experiment #1], use the tank as a storage device for baseboard heat [experiment #2] and then plumb it in as preheated water supply for your domestic hot water [experiment #3].

Looking forward the the results of the experiments!!

Greg L

I'm not sure what LS Farm is talking about but in my experience 110-120 degree water piped through baseboards will equal basically no heat or a cold baseboard. I'd strive for 180 or better so it can drop to 140 at the end of a loop and not shock the boiler.

traderfj, is installing a coil in a stove, he doesn't have a boiler. Trying to heat water enough for baseboard heat may be a bit ambitious for a coil. He doesn't have to worry about cold water shocking his boiler, he will be recirculating the water through the coal,

The minimum effective water temperature for a section of baseboard depends on the planned water temp and the number of feet of baseboard used in each room. You can plan the length of baseboard needed when installing a heating system based on 160, 180 or even 200* water, the most common is 180*.

Like you said 180* water is the planned target, but water that hot may not be available from a coil in a stove. He may be lucky to keep the circulating water at 120*

I use lower water temps to keep coal use down. I don't turn up the water temp untill I need hotter water to increase the heat output from my baseboard units.

A constant 110 or 120* baseboard will add a significant amount of heat to a room, but certainly not as much as a 180* unit. The difference is the constant heat.

Greg L

Don't use anything galvanized anywhere, especially inside the firebox.

You guys have me scared. The melting temp for solder is about 210 degrees. The fitting is attached directly to the SS coil that is above the fire. It's going to get mighty hot and is going to be attached to the outside of the stove. Is there anything I can do to make myself sleep better at night or am I just wasting my energy and should just use solder. I love the idea of using copper it's so easy?