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Need help hooking up indoor wood boiler

I recently purchased and moved into an old house. Sounds fun already right? So there is an oil boiler and a "homemade" indoor wood boiler in the boiler room. "Homemade" is in quotes because it was made by a local welder who is something of a small town legend. There are dozens of boilers made by this guy in the northern NY area according to a local heating professional. That being said, there is no manual or reference for this boiler.

Now, when the late owner of this house passed, his widow cut out EVERYTHING connecting the wood boiler to anything, and had a professional re-plumb the boiler room for the oil boiler only. Now, remember i said old house? The oil boiler consumed ~130 gallons of fuel oil in 2 weeks of weather in the teens. I NEED to get this wood boiler hooked back up, as i have plenty of standing deadwood on my 21 acre lot.

I want to set this up with the wood boiler as primary fuel, but so the oil boiler kicks on if the fire goes out at night or when we're out of the house. I have 3 circulators kicking around, the wood boiler with a blower attached to it (NO wiring remaining), and what appears to be an old standard (no diaphram) expansion tank in the rafters above the wood boiler. have the stove pipe to connect the wood boiler to the same chimney as the oil boiler for the winter, and will install its own stack per code in the summer.

Everything else required for this install i will have to purchase. Not being able to afford 3 more tanks of fuel for this winter, neither can i afford professional labor or expensive components. After extensive research and reading through a hydronic heating textbook, i think i have a solid plan down. But im unsure on a few things.
  • What type of aquastat do i use for the wood boiler? A triple aquastat would work for the blower and circ but i want it to turn the blower off if the fire goes out...
  • Will wiring the two thermostats in parallel to the relay for the distribution loop circ work?
  • Is there anything im missing in this design?
  • im confident in my ability to solder copper tube, have done wiring before but never with 24v switches, anything special i should know?
Im going to the local heating supply store next week to talk to a gentlmen there who can help me but im trying to get as much information as i can first. Thanks in advance for any help.

Also, please dont mind the junk in the picture, i obvioulsy know to clear everything out before starting any workl! :-P






Comments

  • Also, it should be noted that there is only one zone. I intend to keep it that way for now, I just want each boiler to have it's own loop that inject into the distribution loop using the closely spaced tees. I do not want to run the boilers in series for a number of reasons that any heating professional can cite... Trying to balance efficiency with cost here.
  • IronmanIronman Posts: 4,971Member
    edited December 2018
    One properly sized expansion tank in the common loop is all that you should have, not two. And definitely not two different types. The water content of the wood boiler will dictate the size.

    Forget about two thermostats; one is all that's necessary. Use an ETC that's senses the temperature in the wood boiler to select which one receives the call from the thermostat. Run the "W" wire from the stat to the "C" terminal of the ETC. Run the "NC" terminal to activate the oil boiler and the "NO" terminal to activate a relay for the wood boiler circulator.

    When you fire the wood boiler and it gets hot (at least 160*), the ETC will sense it and send the thermostat signal to activate the circulator for the wood boiler. When the water temp in the wood boiler drops below the setting of the ETC, the call will go to the oil boiler.

    ****IDK what controls or safeties are on that wood boiler, but I must caution you about how dangerous an indoor wood boiler can be. I wouldn't have that thing in my house! I sell and install OUTDOOR wood boilers, but an untested, unapproved one is a potential bomb! ****

    At the very least, it should have an operating aquastat, and a high limit aquastat controlling the blower. And a properly sized relief valve.

    Additionally, it should have an emergency dump zone should it over-heat because of too little connected load on a mild day or if the door is somehow not latched tight and there's a runaway fire.

    There are better and safer ways to save on fuel.

    I wouldn't use that thing!
    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • STEVEusaPASTEVEusaPA Posts: 2,830Member
    Neither one of those units look safe to operate. The oil fired boiler's flue pipe in incorrect, for starters.
    The wood boiler may have been disconnected because it failed or is dangerous. It looks like a fire hazard and appears to be way too close to combustibles.
    Hope you don't burn your house down, or die from CO...not being sarcastic but serious.
    steve
  • EastmanEastman Posts: 927Member
    What about just a wood stove with an outside air intake? Wouldn't that be a lot simpler and less expensive? It wouldn't be a primary heat source, but it could seriously cut down the fuel bills.
  • The wood boiler was used by the late owner of the house religiously until the day he passed ( at 80 from unrelated causes). It was disconnected because the widow who had been separated and didn't live here let the fuel oil tank run empty, and the system froze. The boilers had an artful network of manual valves the old man had to switch between boilers. The widow saw no sense in reconnecting the wood boiler when she wasn't living here and didn't want to pay the professional who thawed and repaired the system. Didn't want to pay him any more than she had to anyway.

    I appreciate everybody's concern, but I am going to use it(after a good cleaning), so advice on how to would be appreciated (thx ironman), not simply telling me it looks like a deathtrap.
    My house is currently being heated by the oil boiler as is. Is that barometric damper unnecessary, or plain dangerous?
    And as for a dump zone, I'm assuming that is something more than an expansion tank with a pressure relief valve?
    What is the benefit of the etc control as opposed to two thermostats?
    And ironman are you saying I should have two aquastats on the wood, one for circ and one for blower? The wood boiler has 6 ports coming out of it, the access you see to clean the heat exchanger, the blower and the 2 doors on front. Fire box and heat exchanger walls are solid, needs new gaskets, but other than that it's a simple machine, I just need to make sure proper safeties are integrated. That's why I'm here

    Thanks guys
  • And thanks Eastman but I don't have any wood stove that'll heat a 1700 sq ft house. Nor can I afford one currently
  • And thanks Eastman but I don't have any good spot for a wood stove inside the house without serious changes or renovations. I have a fireplace which I used when I ran out of fuel oil.. it's worked great with 5 electric heaters and 1 cord of wood for 4 days...not sustainable obviously
  • EastmanEastman Posts: 927Member
    I was feeling left out...
  • > @STEVEusaPA said:
    > Neither one of those units look safe to operate. The oil fired boiler's flue pipe in incorrect, for starters.
    > The wood boiler may have been disconnected because it failed or is dangerous. It looks like a fire hazard and appears to be way too close to combustibles.
    > Hope you don't burn your house down, or die from CO...not being sarcastic but serious.

    I have a CO detector in the doorway between boiler room and the main house. As for the combustibles..... Like I said in the initial post in have a lot of junk in the boiler room currently which I will be moving out this weekend before I work on ANYTHING. It's hard to see in the pic, but the wall is lined with 2" thick granite slabs all around the wood boiler.
  • hot_rodhot_rod Posts: 11,272Member
    Yeah, it certainly looks like it has widowmaking potential :) Clearance to combustibles looks questionable, also?

    We want you to be safe and not just economically comfortable.

    It is a challenge to fire a wood boiler to the load without constant stoking and adjusting, buffer tanks are often used to give you some "flywheel".

    They should be piped parallel so either or can add to the load. You never want the back up boiler heating the wood boiler as the heat will go up the wood fired boiler chimney.

    I prefer differential controls so the wood goes off line when it no longer has heat to give, based on two temperature reading sensors. Backup comes on until wood gets back to preset differential and takes over dropping off the backup. It becomes automatic and very adjustable. It is a more complex control to wire, however. I'm not sure how versed you are with line voltage wiring and programing digital controls.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Not very well versed at all @hot rod_7 but I am an extremely quick learner when given the proper information. Could you point me in the direction of some literature regarding differential controls used in such a way? The main limiting factor for me is price of supplies. Control systems can easily reach, I'd like to be around $300 for relays and control devices. Also I have researched dump zones and will include one using a cast iron radiator.
  • hot_rodhot_rod Posts: 11,272Member
    Download and read this trainer. Towards the back are piping and wiring schematic.

    https://www.google.com/search?client=safari&rls=en&q=nyserda+biomass+boiler+training+siegenthaler&ie=UTF-8&oe=UTF-8


    This is close to what you want, delete the outdoor reset control. 156 is a Tekmar brand differential controller, you can find less expensive models at www.alphathermalsystems.com
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • STEVEusaPASTEVEusaPA Posts: 2,830Member
    You’re not going to do it for $300
    steve
  • IronmanIronman Posts: 4,971Member

    You’re not going to do it for $300

    Or anywhere close.

    Bob Boan


    You can choose to do what you want, but you cannot choose the consequences.
  • HEATthis08HEATthis08 Posts: 4Member
    I know the homeowner has the right to work on his own house but that doesn't mean you should!! I urge you to find a real wood burning boiler and stay away from this one you have I am sure you can find one very reasonable in your local swap sites best of luck and stay safe..
  • cuttercutter Posts: 252Member
    I have been heating my house for the last 30 years with an improperly plumbed and wired wood boiler. With the help of heating professionals on this site I have re-plumbed and wired my boilers. The wiring is my own design because I want to run one or the other, not both at the same time. My other boiler is oil fired.

    The cost of materials to re-plumb and wire was over $5,000.00. It was not an easy task. It is longer than a weekend job. Wood is dirty and burning wood is dirty. A dry place to store your winters supply of wood is needed. I bought this boiler from a guy that could not heat his house with it. He was trying to burn wet wood, that does not work. I have included one picture showing part of my system.

  • leonzleonz Posts: 324Member

    I recently purchased and moved into an old house. Sounds fun already right? So there is an oil boiler and a "homemade" indoor wood boiler in the boiler room. "Homemade" is in quotes because it was made by a local welder who is something of a small town legend. There are dozens of boilers made by this guy in the northern NY area according to a local heating professional. That being said, there is no manual or reference for this boiler.

    Now, when the late owner of this house passed, his widow cut out EVERYTHING connecting the wood boiler to anything, and had a professional re-plumb the boiler room for the oil boiler only. Now, remember i said old house? The oil boiler consumed ~130 gallons of fuel oil in 2 weeks of weather in the teens. I NEED to get this wood boiler hooked back up, as i have plenty of standing deadwood on my 21 acre lot.

    I want to set this up with the wood boiler as primary fuel, but so the oil boiler kicks on if the fire goes out at night or when we're out of the house. I have 3 circulators kicking around, the wood boiler with a blower attached to it (NO wiring remaining), and what appears to be an old standard (no diaphram) expansion tank in the rafters above the wood boiler. have the stove pipe to connect the wood boiler to the same chimney as the oil boiler for the winter, and will install its own stack per code in the summer.

    Everything else required for this install i will have to purchase. Not being able to afford 3 more tanks of fuel for this winter, neither can i afford professional labor or expensive components. After extensive research and reading through a hydronic heating textbook, i think i have a solid plan down. But im unsure on a few things.

    • What type of aquastat do i use for the wood boiler? A triple aquastat would work for the blower and circ but i want it to turn the blower off if the fire goes out...
    • Will wiring the two thermostats in parallel to the relay for the distribution loop circ work?
    • Is there anything im missing in this design?
    • im confident in my ability to solder copper tube, have done wiring before but never with 24v switches, anything special i should know?
    Im going to the local heating supply store next week to talk to a gentlmen there who can help me but im trying to get as much information as i can first. Thanks in advance for any help.

    Also, please dont mind the junk in the picture, i obvioulsy know to clear everything out before starting any workl! :-P






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    As an owner of a hand fired wood and coal boiler when I heated with 33 years I will give you plenty of advice as it is earned from experience.

    The wood boiler you have there needs a domestic coil to seal the steam chest and it appears that the gentleman that welded these boilers together used an Axeman Anderson trombone type domestic hot water coil for making hot water.

    The coil you need would be the larger model for an Axeman Anderson S260 coal stoker and for the money you need to spend for that domestic coil to replace the missing one you would be much better off with a new coal stoker boiler.

    The oil boiler installation, the wood boiler and the existing plumbing for both units needs to be ripped out and scrapped as it will not pass the National Plumbing Code minimums for clearances for oil or wood burning appliances.

    You can leave the steel compression tank in the ceiling and add an airtrol valve to upgrade it as it is all you need to regulate the water pressure in your hot water seating system.

    Your system needs a lot of work and candidly installing an AHS S130 coal stoker to burn pea coal to make all your domestic hot water the year round and heat your home with much less coal.
    You could also install a Leisureline WL110 coal stoker boiler to make all your domestic water and heat the home as well.

    Both the old boilers would be red tagged by a plumbing inspector and you would not be able to continue using the oil boiler.
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