I have been collecting parts for a boiler I want to build for several years. I'm not quite ready to build my big boiler and have been trying to get by with an old wood boiler that is basically just a 30 gal round tank with 9 fire tubes running through it. The boiler tank just sit on top of a fire box that is roughly 2' X 3' on the inside with a firebrick lining.
I know an updraft system like this is not the best way to heat water but I had it so I figured I might as well try and make due until I got my shop finished and could start on my new SS boiler. I had it set up as an open system that took the water out of the boiler and it ran over to a hundred or so gallon plastic tank and from there I pumped that water to my manifold and through the 7 loops that are buried in my concrete floor. That was working fairly well until I discovered that one or two of the tubes has started leaking and for the rest of the winter I got by but it was a lot of work keeping the creosote it was making at bay and throwing enough wood in the firebox to keep it hot enough to keep things from freezing up.
Before the next season I took the top and bottom of the tank off and welded in new, 2" schedule 40 black iron pipes and put new plate on the top and bottom. I figured this would get me by until I could build a whole new one. I think that would have worked good for a few years if I had not screwed up and fired it up with the new air system I had also added to get a little hotter burn and didn't come back soon enough to start my pump to the manifold.
When I rebuilt the boiler I moved the stove to another part of the shop that didn't have enough room for the buffer tank and I just had the system piped into and out of the boiler in one loop through the floor. Actually I wasn't trying to heat the building but just keep enough heat in the floor to keep it from freezing. The way It was would have worked well enough to get by until I could do better. That is if I had not started it up and forgot to come back and start up the pump to circulate new water through the boiler before it was already overheated. When I came in it was really hot and when I turned on the pump water went everywhere from out of the pump housing and I didn't know if it was circulating at all so the only thing I could think of next was to turn on the fill valve to let in some cold water and when I did that there was a clunk and a clang from within the boiler and as it did cool back down it also broke something inside and for the rest of that winter I had to deal with leaking tubes again.
I know this is a long way around to get to the question I had about heat exchangers but I wanted to explain a little about what I had going on. This year as usual time has sneaked up on me and here it is time for heat again and I still haven't gotten around to building my new boiler.
I ditched the old boiler because I didn't want to mess with that anymore and I have put together a new SS top for the stove that I made out of 4X6, 316L stainless box tube that is 1/4" thick. I welded them in so that the water would have an in and a out and the flu would exit in the center of the configuration and out through a schedule 40 flu pipe I welded up.
After reading page after page on this site I figured out that my water going back into the boiler was too cold and was partly the reason for the stove making so much creosote so I decided to go back to some kind of buffer tank. I have a 40 gal water heater I was going to add to the system later on and I thought I would just use this as a buffer tank and pull water from it to put some hot water into the floor.
I also have a large heat exchanger I got from where my son works that was used to cool refrigerant and I thought it would work for what I want to do just as well. It's I guess what you would call a shell heat exchanger. It has copper tubes on the inside and a steel schedule 80 shell around the tubes. The shell part holds 17 gals of water and the tube section has 22 gal capacity. The way it worked was that the refrigerant traveled through the shell side and water flowed through the tubes.
What I was wondering was what would be the best way to plum this thing into the system. I mean which side would I use for the supply from the buffer tank? The tubes or the shell?
Hear again I know this is not going to be a perfect setup and just a means to hopefully keep the floor from freezing as the heat from the stove puts out enough heat to heat the back part of the building that don't have tubes in the floor.
I know an updraft system like this is not the best way to heat water but I had it so I figured I might as well try and make due until I got my shop finished and could start on my new SS boiler. I had it set up as an open system that took the water out of the boiler and it ran over to a hundred or so gallon plastic tank and from there I pumped that water to my manifold and through the 7 loops that are buried in my concrete floor. That was working fairly well until I discovered that one or two of the tubes has started leaking and for the rest of the winter I got by but it was a lot of work keeping the creosote it was making at bay and throwing enough wood in the firebox to keep it hot enough to keep things from freezing up.
Before the next season I took the top and bottom of the tank off and welded in new, 2" schedule 40 black iron pipes and put new plate on the top and bottom. I figured this would get me by until I could build a whole new one. I think that would have worked good for a few years if I had not screwed up and fired it up with the new air system I had also added to get a little hotter burn and didn't come back soon enough to start my pump to the manifold.
When I rebuilt the boiler I moved the stove to another part of the shop that didn't have enough room for the buffer tank and I just had the system piped into and out of the boiler in one loop through the floor. Actually I wasn't trying to heat the building but just keep enough heat in the floor to keep it from freezing. The way It was would have worked well enough to get by until I could do better. That is if I had not started it up and forgot to come back and start up the pump to circulate new water through the boiler before it was already overheated. When I came in it was really hot and when I turned on the pump water went everywhere from out of the pump housing and I didn't know if it was circulating at all so the only thing I could think of next was to turn on the fill valve to let in some cold water and when I did that there was a clunk and a clang from within the boiler and as it did cool back down it also broke something inside and for the rest of that winter I had to deal with leaking tubes again.
I know this is a long way around to get to the question I had about heat exchangers but I wanted to explain a little about what I had going on. This year as usual time has sneaked up on me and here it is time for heat again and I still haven't gotten around to building my new boiler.
I ditched the old boiler because I didn't want to mess with that anymore and I have put together a new SS top for the stove that I made out of 4X6, 316L stainless box tube that is 1/4" thick. I welded them in so that the water would have an in and a out and the flu would exit in the center of the configuration and out through a schedule 40 flu pipe I welded up.
After reading page after page on this site I figured out that my water going back into the boiler was too cold and was partly the reason for the stove making so much creosote so I decided to go back to some kind of buffer tank. I have a 40 gal water heater I was going to add to the system later on and I thought I would just use this as a buffer tank and pull water from it to put some hot water into the floor.
I also have a large heat exchanger I got from where my son works that was used to cool refrigerant and I thought it would work for what I want to do just as well. It's I guess what you would call a shell heat exchanger. It has copper tubes on the inside and a steel schedule 80 shell around the tubes. The shell part holds 17 gals of water and the tube section has 22 gal capacity. The way it worked was that the refrigerant traveled through the shell side and water flowed through the tubes.
What I was wondering was what would be the best way to plum this thing into the system. I mean which side would I use for the supply from the buffer tank? The tubes or the shell?
Hear again I know this is not going to be a perfect setup and just a means to hopefully keep the floor from freezing as the heat from the stove puts out enough heat to heat the back part of the building that don't have tubes in the floor.
