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Help... Three zone home

udhoop Member Posts: 4
I need some help/ advice prior to discussing this issue with our contractor again. We have a new home with radiant floor heat. We have three zones with a thermostat for each. (Basement, main floor, upstairs)Each level has its own manifold as well which runs three to four loops. It is heated by a Lochinvar Noble combi gas boiler. When having this installed the idea was that each zone would work independently based on its own thermostat. However, I have discovered that when one zone calls for heat we have heat going to all three manifolds/zones. There is a pump for each zone. So as an example, if I go upstairs and bump up my thermostat so that zone calls for heat then go downstairs I will see that our boiler has kicked on and I can feel the pump for the upstairs zone working. So that is good. However, if I go around to the other manifolds each has hot water going through them. Like too hot too touch water. While their pumps don't seem to he actively working its as if they are open and the whole system is receiving heat. Our contractor says they receive "residual" heat from "some" water passing through. However, a friend of ours who also has this same design and setup says this should not be happening. When he has a zone call for heat only that zone is receiving heat and his other manifolds are cool to the touch. The example I gave happens regardless of which zone I bump up. We are in Nothern MI so its not a big deal with regards to the main floor and upper level but with our basement receiving heat every time it is a sauna! Code required us to put down r-15 foamboard which we stapled too and then the whole basement has r-10 foamboard around the exterior so it keeps the heat in extremely well. Any ideas on why all three zones are receiving heat when only one zone calls for it?


  • udhoop
    udhoop Member Posts: 4
    Here are a few pictures
  • udhoop
    udhoop Member Posts: 4
    The pump in the upper left is for our upstairs. The pump just to the right up that is for the main floor and the pump to the far right is for the basement with its manifold directly below it.
  • DanBee
    DanBee Member Posts: 3
    There are no check valves on the return lines of the zones.
    when the boiler pump circulates it will increase pressure and push water into each zone even if the zone pumps are not calling.
    some circ pumps have built in check valves. It appears that yours do not.
    Start with that. it is not a huge modification to do.
  • DZoro
    DZoro Member Posts: 1,048
    You are piped wrong, proper piping is on page 37 of the installation manual. Will also show where to put the flow check valves, and how to pipe primary secondary. You also put in a "extra" pump. This is not a good place for pex piping.....
  • hot_rod
    hot_rod Member Posts: 18,190
    looks like an attempt at primary secondary piping that is incorrect The manual shows better piping options
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    HVACNUT Member Posts: 4,856
    Does that green sticker say 'Final Inspection'?
  • Zman
    Zman Member Posts: 7,433
    Can you take a picture of the boiler with the cover off? I believe there is a circulator inside.
    Aside from the pex and crimp fittings being just plain ugly, it is piped completely wrong.
    I think you need to find a contractor who can read to repipe it, preferably in copper.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein