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Newmac BC160 feedback

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by cricco, Mar 25, 2008.

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  1. cricco

    cricco New Member

    Joined:
    Mar 25, 2008
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    Loc:
    Western, Ma
    Greetiings everyone. I'm new here, and this is my first post. My wife and I have just installed a Newmac BC160 combination oil/wood boiler in our new construction home. I wish that I had found this site before getting myself in so deep. We have approximately 2800 sq ft including our heated garage. I am hoping to tell you all about my experience, and hopefully get some advice/tips from people with more experience. I'll start by saying that I got the idea of using a combo boiler with our baseboard hot water heat and indirect DHW because of the rising cost of oil, and the fact that we have acess to many acres of woods for cord wood. I initially purchased the boiler, 35 feet of Selkirk metalbestos 8" chimmney, and most of the hardware to install it for about $16,000. I then had to pay a plumber $5,500 to install it including the hot water heater (56 gallon Weil Mclean gold) and the garage heat (18,000 btu sterling heater). My electrician robbed me of $1,700 to wire the boiler. All of this and a few other expenses have me totaling about $24,000 for this system. I can't help but feel that I've made a mistake. Now, I have been using wood to heat the home (we haven't moved in yet). I am finding that this thing uses a LOT of wood. We have used about 3/4 cord in a month. When run on oil, it is burning 1 gph. this is a huge oil hog in my opinion. My biggest problem is creosote. I am using wood that is about a year seasoned. I have found that if I load up the stove, it will burn at about 425 degrees (magnetic flu thermometer between the boiler and flue) for about 10 minutes, and then it reaches temp (170 deg.) and shuts down the draft fan. This causes the fire to smolder until the system temp drops to about 155 degrees. The smoke is causing a huge creosote problem. The inside of the firebox is coated in a glassy glaze of creosote. I tried cleaning the heat transfer tubes with the supplied brush, but the creosote is too thick. is there a way to clean this stuff? Also, can anyone give me any ideas on how to make this system run more efficiently? Is there a way to get it to burn hotter and burn off some of the creosote? I have tried smaller hotter fires, but man, that stuff just won't burn off. Thanks for any help.

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  2. steam man

    steam man Minister of Fire

    Joined:
    Jan 19, 2008
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    While you wait for the official webmaster greeting I'll give you my thoughts. Don't panic yet. 3/4 of a cord of wood/month doesn't sound too over the top for the coldest months. A heat exchanger that is full of crud will hurt your efficiency. Go to www.rutland.com. They make a range of chemical removers/maintenance products for wood burning. Their site has some good educational info on creasote problems. A 1gph burner isn't bad uness it is running 24/7. You should have an idea of your heat loss. That will tell you how you actually stand. I have a 1.2 gph rating and mine runs about 1 hour/day (1.2 gallons) when I supplement with wood to only heat DHW. I will be out of wood by tomorrow and I don't want to think about that. I think your 170 deg temp is too low. I would set it at least 180 (if not higher) to run it a little hotter to keep the creasote from building. I will say that a wood boiler, especially a non gassifier will need storage. The mantra on this site seems to be run it hot and hard and don't smolder. You should think about thermal storage when wood burning so you don't off-cycle and smolder.

    Start reading all the past post you can on this site. You'll get some good advise to help fine tune your situation. There's a number of people on here that have had growing pains learning how to efficiently burn wood.
  3. webbie

    webbie Seasoned Moderator Staff Member

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    Western Mass.
    Creosote will always form on relatively cold surfaces. A more important measure is the creosote in the chimney itself as well as the amount of smoke coming out.

    I concur with steam man that the ultimate solution would be adding storage to the system. This would allow you to blow through the wood at a higher rate - and use that more efficient burn to charge up the storage - then your house would work off the storage for many hours.

    Another little secret is to use 4-way mixing valves on large zones which need some heat most of the time. That effectively adds those zones to the heat storage capacity of the system, so that the unit does not operate on a purely "on-off" type of control.
  4. Eric Johnson

    Eric Johnson Mod Emeritus

    Joined:
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    Welcome to the Boiler Room, Newmac. Sorry to hear about your problems and deep investment.

    I would concur that it's too early to panic. Any woodburning appliance takes at least a year to get good at operating, and a conventional combination boiler like yours will produce creosote until you figure out the best way to run the thing. Hotter is usually better. Dry wood is always better.

    I ran a conventional combination boiler for about 9 years (Marathon Logwood), and I burned a lot more wood the first year than I did after that. I got a lot of creosote, too, but not always, though I never really figured that one out.

    I'll give your comments some thought and let you know if anything comes to mind.
  5. cricco

    cricco New Member

    Joined:
    Mar 25, 2008
    Messages:
    49
    Loc:
    Western, Ma
    Thank you all for the input. I do have a mixing valve for the 2 main zones to the house (1st and second floor) but this was purely done to prevent the PEX tubing from melting down. I am getting a little better at burning wood. I have figured out that if I load up the boiler at night, I can get a really roaring fire going first thing in the morning which helps to burn off some of the creosote. I have been reading a little about this "storage" system. I don't really understand it. Could anyone send me some detailed info on how I could add this to my system? Diagrams would be helpful. Also, a thorough explanation of how it is suppose to work would help too. Thanks again.
  6. Eric Johnson

    Eric Johnson Mod Emeritus

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    I think it's been pretty thoroughly discussed in various threads. I would do a title search for words like "Storage" "Tank" "Storage Tank" "Buffer" etc.

    Basically, hot water storage is like a battery--you stash heat in the tank when it's not being used to heat the house, and then you recover it later (usually through a heat exchanger) to extend the time between firings. In your case, it would allow you to fire your boiler hard for greatest efficiency, especially on warmer days when it would otherwise idle and create creosote.
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