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base getting hot when indirect water heater zone running

Andre Member Posts: 11
I just did a boiler replacement at my home. It originaly had two circulater zones, one for downstairs and one for upstairs. I added an indirect water heater as a third zone. Problem: When there is a call for a lot of hot water and the water heater zone runs alot, the baseboards from the other two zones start getting hot when there is no call for heat, the circulators are off. I have new flow valves on all three zones on the supply side, right after each circulator. Why is this happening?


  • Kal Row
    Kal Row Member Posts: 1,520
    Gravity circulation…

    It’s how it all worked before circulators
    Cooler water this thicker and heavier than warmer thinner water and the will displace each other even in a single ¾ inch pipe, – the solution is, “spring checks” on any leg that doesn’t have a zone valve in it, so that the water only flows when you want it to, same goes for the indirect hot water zone, even if it’s reverse piped and you have heat trap loops – if the height and temp difference is enough, the displacement acceleration will drop the cooler water right through even a 2ft heat trap loop – that’s why I always use circulators with built in spring checks, taco xxxIFC or grunfos xxxFC or you can use the new B&G flange ball valve with the built-in spring check - and i put the zone valves on the supply side to get a positive zone disconnect at the hottest point
  • Bill_39
    Bill_39 Member Posts: 69
    make sure the

    flo checks are in the closed position. If they are set to manual then you can still get flow through them every time a zone comes on
  • Weezbo
    Weezbo Member Posts: 6,232
    the piping has to be part of the stradgey......

    adding on pieces ad infinitum may Look cool however the piping layout has a heck of alot to do with control.........as you are lousy with time and slow on dough repipe it right quick...think it out so as to look simple and function properly.or add check valves ,maybe a coupel zone valves,a couple ifc pumps, thermal traps,modulating by pass esp zone valve,.....
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