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Wood boiler with LP boiler

Mal74
Mal74 Member Posts: 3
My outdoor boiler is a Heatmaster SS 4000 hooked up to my home and poleshed. The shed has infloor heat and seems to work fine. My issue is in the home. My indoor boiler is a Lennox Conservator 75,000 BTU.When the wood boiler is used the gas boiler calls for gas and stays on while circulating. It is a radiant baseboard heating system and it only heats half of the house. Any help will be appreciated and thanks for the info.

Comments

  • Zman
    Zman Member Posts: 7,435
    You are going to have to give us more to work from. There are dozens of ways to pipe wood boilers.
    Pictures and/or drawings would be a good start.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    kcopp
  • Mal74
    Mal74 Member Posts: 3
    Turns out a bypass valve was left open, the house now has heat but does not explain why the gas still kicks on. Will keep posted.
  • Ironman
    Ironman Member Posts: 7,088
    One of the most common (but not correct) ways is to connect the wood boiler to the house system and then simply lower the setting on the boiler's aquastat to 140*. If the wood boiler supplies water temps above that, the gas boiler should remain off.

    The problem with this is that if the wood boiler is not fired, 140* from the gas boiler is not hot enough to heat the house in colder weather. Then the aquastat gets turned back up to 180*. Maybe that's your scenario?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • hot_rod
    hot_rod Member Posts: 18,281
    They tend to get piped in series often, which makes them compromised and less efficient as they heat the fuel fired boiler aka a cooling tower🤪
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GroundUp
    GroundUp Member Posts: 1,496
    Put an aquastat on your incoming OWB supply line to keep the Lennox from firing until supply water drops below 130 or 140 or whatever, then the gas boiler aquastat would take over and heat back up to 180 or whatever you're running.

    Is this unit fed via a plate exchanger from the OWB or are you running the Lennox atmospheric like the Heatmaster?
  • Mal74
    Mal74 Member Posts: 3
    None of this sounds like an easy fix. Will make some calls. Thanks everyone.
  • EYoder
    EYoder Member Posts: 60
    edited October 2018
    > @GroundUp said:
    > Put an aquastat on your incoming OWB supply line to keep the Lennox from firing until supply water drops below 130 or 140 or whatever, then the gas boiler aquastat would take over and heat back up to 180 or whatever you're running.
    >
    > Is this unit fed via a plate exchanger from the OWB or are you running the Lennox atmospheric like the Heatmaster?

    I would normally do exactly this with a Ranco temp control sensing incoming water temp. And definitely separate the two systems with a plate exchanger.
  • GroundUp
    GroundUp Member Posts: 1,496
    Mal74 said:

    None of this sounds like an easy fix. Will make some calls. Thanks everyone.

    The aquastat will take 15 minutes and a screwdriver. No need for calls