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In flue heat exchanger?

ChrisJ
ChrisJ Member Posts: 11,561
I've seen this mentioned a few times on the wall and am curious if these things still exist?

I can't remember the last post, but someone mentioned, I think it was in the 1970s, adding a coil into the flue to pull heat from the flue gasses.

If they can still be found, my objective would be to add some heat to my kitchen floor over a cold crawlspace. Last winter I measured 38F with my IR thermometer on a cold and windy night. Obviously I need to fix some drafts but adding some heat wouldn't hurt either and this would be 100% free heat aside from the pump running.

If an off the shelf solution is not available, would a home made one be viable?

This would be set up to run the pump whenever the burner is on for obvious reasons.
Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment

Comments

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    I wouldn't recommend it based on pictures of your venting system. You will rob so much heat out of the flue gas that they are guaranteed to condense, and the WILL take out your chimney and connected venting system from the acidic condensation.

    There is a reason they are no longer available. People died from them. Industrially, where you have total and complete control, they make good sense. Residentially, they are a death trap.

    Try some caulk and insulation to increase comfort AND reduce energy consumption.

    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
    ChrisJBob Bona_4Charlie from wmass
  • ChrisJ
    ChrisJ Member Posts: 11,561
    Hi Mark,

    I don't care for death traps. They tend to interrupt the flow of my day. :/

    Thank you for commenting. I didn't know if they were still available or not.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JUGHNE
    JUGHNE Member Posts: 8,312
    There were many "add on" products from that era. As Mark said people died from them. But probably many more heat exchangers, venting systems and chimneys died also.
    SWEIChrisJ
  • Bob Bona_4
    Bob Bona_4 Member Posts: 2,083
    I remember removing them on OIL boilers 25 plus years ago. Flair made them? I can't even fathom them on a gas application!
  • vaporvac
    vaporvac Member Posts: 1,520
    I guess a small HW loop is out of the question?
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
    Bob Bona_4
  • ChrisJ
    ChrisJ Member Posts: 11,561
    vaporvac said:

    I guess a small HW loop is out of the question?

    Yeah,
    That's what I got out of the responses. :)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • JUGHNE
    JUGHNE Member Posts: 8,312
    You could do a HW loop with steam condensate from the bottom of boiler.
    ChrisJ
  • ChrisJ
    ChrisJ Member Posts: 11,561
    JUGHNE said:

    You could do a HW loop with steam condensate from the bottom of boiler.

    I was hoping to do something to gain efficiency. I'll need to pay to run that hot water loop. ;)
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • FranklinD
    FranklinD Member Posts: 399
    I remember Dan making reference to them in his blog post about visiting the Starbuck family shop...it's one of my favorite posts so I have it bookmarked. Here's the quote:

    "They put a "fuel saver" coil in the breeching a long time ago to transfer some of the heat from the flue gasses into the system water. Naturally, it made the gasses condense and it's long since rotted out, but it's still hanging there as a good lesson in basic science."

    - See more at: https://heatinghelp.com/blog/remembering-the-starbuck-family/#sthash.N7xZbsYw.dpuf

    I see what you're driving at, though...a condensing steam/hot water combo boiler.
    Ford Master Technician, "Tinkerer of Terror"
    Police & Fire Equipment Lead Mechanic, NW WI
    Lover of Old Homes & Gravity Hot Water Systems
    ChrisJ
  • Tim McElwain
    Tim McElwain Member Posts: 4,466
    Most of these devices are no longer allowed on gas or oil systems. They are Carbon monoxide waiting to happen. There were incidents in the past concerning the use of these and all heat activated vent dampers. Electric vent dampers are all that is allowed. Even then I would still add a spill switch (blocked vent switch).
  • ChrisJ
    ChrisJ Member Posts: 11,561

    Most of these devices are no longer allowed on gas or oil systems. They are Carbon monoxide waiting to happen. There were incidents in the past concerning the use of these and all heat activated vent dampers. Electric vent dampers are all that is allowed. Even then I would still add a spill switch (blocked vent switch).

    Tim, unrelated but is it possible to add a spill switch to the outerjacket of the B vent? I don't know what temperature that actually reaches under normal operation.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • jumper
    jumper Member Posts: 1,618
    Like everything it depends.An engineered add on can recover energy from an inefficient device. In the seventies gas converted boilers had available waste heat.But what to do with it?
  • RobG
    RobG Member Posts: 1,850
    What about a stainless coil in the exhaust of a mod-con as a hot water preheater? The mod-cons exhaust doesn't get hot enough to create steam and it would simply cause more flue gas condensation? It would of course have to be manufacturer approved but I cant see why it wouldn't work.
    SWEI
  • ChrisJ
    ChrisJ Member Posts: 11,561
    RobG said:

    What about a stainless coil in the exhaust of a mod-con as a hot water preheater? The mod-cons exhaust doesn't get hot enough to create steam and it would simply cause more flue gas condensation? It would of course have to be manufacturer approved but I cant see why it wouldn't work.

    How about taking a cast iron steam boiler, installing a heat exchanger and converting it to using an inducer and direct vent?

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Jack
    Jack Member Posts: 1,045
    I made a bunch of these back in the 70's for wood stoves. They teach you a lot about creosote production...in retrospect.
    I took a 7" wooden post. Took a wrap around and laid out a spiral. Took a router with a round cove bit to the spiral. Took a coil of 3/4 soft copper and nailed an end off. Pulled it straight with a come along. Filled the tubing with fine sand and blocked the ends. Nailed one end to the wood form and with the attached handle turned the tubing into a spiral. The wooden form would collapse into the center leaving a nice 3/4 copper spiral that would wrap around a piece of 6" stove pipe. A piece of 7" would form the outer piece and the stubs of copper would stick out of that. Install it in the stovepipe and the water was hot
    I was living in a yurt in upstate NY at the time heating with wood. Water out of a creek, 1propane light. Outhouse. There was a non pressurized tank above the stove so the hot water thermosiphoned to the tank. Had to be careful of boiling water coming out of the shower, but in the middle of winter a couple miles from the nearest road it was nice having hot water. Did I mention creosote?
    SWEIChrisJvaporvac
  • vaporvac
    vaporvac Member Posts: 1,520
    I think we need to explore this further: I was living in a yurt in upstate NY...
    Those are words one doesn't hear much these days! :} Everyone seems to have headed off in the opposite direction.
    Two-pipe Trane vaporvacuum system; 1466 edr
    Twinned, staged Slantfin TR50s piped into 4" header with Riello G400 burners; 240K lead, 200K lag Btus. Controlled by Taco Relay and Honeywell RTH6580WF
  • Dan Foley
    Dan Foley Member Posts: 1,235
    I've taken a few of these out over the years. Tim is right, these are an accident waiting to happen. CO, rotted out chimneys, combustion gas leakage into the living space....

    - DF
  • Jamie Hall
    Jamie Hall Member Posts: 15,819
    OK, Colleen -- I'll date myself... let's just say that Woodstock was one heck of a party. In upstate (sort of) New York...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    vaporvacZman
  • JUGHNE
    JUGHNE Member Posts: 8,312
    If you consistently burn wood for your main heat source then you must be vigilant and aware the entire time the fire is burning. (That is if you want to wake up on the green side of the grass every morning.)

    There were and still are many devices like the "Magic Heet" in use, some even come with the stove/furnace. Some had a creosote scrapper device built in and you are to operate that occasionally to clean the heat exchanger.

    Responsible wood burning owners know that creosote is a constant threat and take actions to maintain safety. For me it was like sub-consciously driving a car, just knew that there was something there to tend to.

    But to put add on devices on a system that is started with a flip of a switch upstairs and never the basement never visited is asking for problems.
  • Jack
    Jack Member Posts: 1,045
    As to the yurt, and Dan I must ask for your forbearance, I was an apprentice in local 109 in Ithaca, NY. 109, unfortunately, has been merged into Syracuse to gain more pension funds for the UA. In my opinion, the pension funds are all that drives unions today. I spent almost two of my five year apprenticeship on the bench. I learned the trade on the road. The day I turned out of my time I put my travel card in and never worked at home again. Texas, Ontario, Washington, Colorado, Nebraska, Alberta, California, Arizona, Kansas, NY and others, proving the axiom that the rolling stone gathers no moss. In those days I could pass any welding test anywhere. The two best jobs I have had working with the tools were shutdowns on nuclear plants. I picked up some "zoomies" (radiation) and now have a half life of my own, but they were great jobs with great, highly skilled guys.

    Apprentices didn't make a lot of dough, and less when you were on the bench, and the yurt and the experience of living in it was terrific and rent free. I'd go into town twice a week for UA classes. The classes were miserable, you can only read the UPC out loud with no discussion or explanation of it so many times and as soon as I could I went to the welding classes. They were good and I became good at it. It is my primary hobby still. I have never, before or since I lived in the yurt read as much as I did then. Being kinda sorta semi-retired, I'm trying to catch up with my yurt reading level. So much to learn. So little time; and that becomes more apparent as you age;)

    Today, with the communication compression, it is almost impossible to shut it down. That said, if you can get a couple weeks and find a camp someplace where you can shut it down (no radio, tv, phone, pad, computer...print only), you will not regret the experience. I would recommend doing it in the winter where it snows a lot. Idyllic, really! Try it, you will not be disappointed. Cold and wet maybe, but good overall.

    And Woodstock was a great time. I wish I remembered more of it, but that was the life I was living.

    Reading this over, in spite of what it sounds like my experiences in the Union part of the trade were really great. Some really fine men helped me out, although I was to young and dense to realize it at the time. I was the first hippy (1970) to work in the union trades in that area. It was interesting, to say the least! I was also the last all white apprenticeship class. Affirmative Action, which imho was a good idea, was so very poorly handled. It ended up unfair to everyone, perhaps most of all the black kids who got into it.

    In fairness, I must say that it was my experience in the trade that gave me the background and experience to be successful, well, reasonably successful, in the Rep business. More of you should try it! The barriers to entry are higher today, but it is a good career and agencies need people who can talk the talk and walk the walk. Technical Sales is a gas! And you get to tell stories!
    SWEIRobGvaporvac
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