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Current Boiler Setup (In Series)- How to change to Parallel piping and is it worth the trouble?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by NewBoiler, Jul 15, 2011.

  1. NewBoiler

    NewBoiler New Member

    Joined:
    Feb 23, 2010
    Messages:
    45
    Loc:
    Canada
    I have a Kerr TW2000 connected to my oil boiler in an in-series arrangement as shown in the attached diagram. The boilers heat three floors with a combination of cast iron and baseboard heaters. The house is about 2700 sq/ft , counting the basement. I ran this setup last winter and used (estimate) between 10- 11 cord.

    I have always read that the parallel piping setup is more efficient in that it doesn't heat the other boiler and you do not lose heat up the chimney. The current in-series setup worked fine last year, my only complaint could be the amount of wood burned. If I were to go through the troubel of re-piping it to a parallel setup, would I potentially burn less wood?

    If Yes, what would be the easiest way to change the existng piping, based on the diagram below?

    Thanks

    Attached Files:

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  2. in hot water

    in hot water New Member

    Joined:
    Jul 31, 2008
    Messages:
    895
    Loc:
    SW Missouri
    Here is one method with a bit of primary secondary to allow multiple temperatures. Also a means to create DHW. photo credit John Siegenthaler

    Attached Files:

  3. sgrenier35

    sgrenier35 Member

    Joined:
    Jan 8, 2010
    Messages:
    46
    "I have always read that the parallel piping setup is more efficient in that it doesn’t heat the other boiler and you do not lose heat up the chimney. The current in-series setup worked fine last year, my only complaint could be the amount of wood burned. If I were to go through the troubel of re-piping it to a parallel setup, would I potentially burn less wood?"

    The simple answer is yes you would burn less wood. How much less maybe half a cord/ year. Will the money saved on wood offset the price of repiping your system? probably not for many years. Also you will burn more oil heating up the oil boiler from cold when your wood fire dies down, than your current system.In my opinion, the smarter approach would be to keep saving oil for a few years with your kerr. Invest in a gassifier in a few years, and re pipe then, as you will have to do some replumbing to make the gassifier work with your system.
  4. willworkforwood

    willworkforwood Feeling the Heat

    Joined:
    Jan 20, 2009
    Messages:
    459
    Loc:
    Central Ma
    I installed my gasser in series with the OB three years ago because it was much faster and easier to just loop the WB into the OB and use the existing OB controls and leave all of the zone piping asis. I had planned on changing the piping to parallel down the road when time allowed, but have decided to not go ahead with that change. There is around a 2 degree water temp differential through the OB, but I believe that most of that is due to standby loses from the OB itself (helping to heat the house), versus heat lost going up the stack. For my situation (no-cost wood), I have no problem cutting the small amount of extra wood needed to offset whatever is going up the OB stack. I just can't justify spending the $$ for the piping redo and new controls. Regarding wood usage, I did see a big drop in usage once everything was fully seasoned (starting with year #2). Was all of your wood seasoned to 20% or less last year? If not, complete seasoning would be an opportunity to cut down your wood usage, maybe significantly.
  5. thehaas

    thehaas Member

    Joined:
    Nov 22, 2009
    Messages:
    10
    Loc:
    north east pa
    series is best if wood boilers top out let goes into original boiloer return heat rises so both will maintain same heat.had mine hooked up tandem did not heat near as good.i saw 3 valve set up on web for when shutting down boiler in summer .my videos are on you tube under bodyshop18336
  6. JrCRXHF

    JrCRXHF Burning Hunk

    Joined:
    Apr 28, 2008
    Messages:
    207
    Loc:
    Mid, Michigan
    I am going to do a plate heat exchanger to keep my two boilers separate from each other. Put the exchanger before the gas boiler and if the water is already warm enough then the gas boiler won't add any heat to it and it will just pump the warmed water from the wood boiler.

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