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Multi-zone heating

ROCP Member Posts: 9
Hi all,

I am experiencing an issue with my heating ever since I had my boiler "flushed" to remove air pockets. My setup is as follows, I have four heating zones. Zone 1 = Basement, Zone 2 = 1st floor, Zone 3 = Master bedroom section of the house and Zone 4 = Kids side of the house. The issue is as follows, the basement will call for heat but will not heat the basement until the first floor kicks in almost as if the basement Zone is dependant of the first floor zone. I have replaced the basement thermostat and it did not resolve the issue. I also checked to see if maybe the basement thermostat was not calling for heat, which turned out to be false because it does call for heat and the little slider on the zone can be moved freely when the thermostat is calling for heat. Since the zone appears to be "working" I have not tried to replace the zone valve itself and think it may be another issue. However I am no expert at this and therefore I have come here to see if anyone has experienced this type of issue and can offer some assistance before I have to get the heating company out to my houes again. Any help is greatly appreciated.


  • hot_rod
    hot_rod Member Posts: 19,976
    A quick check would be to turn all stats down then manually open the zone valves and see if you get circulation. Depending on the type of zone valve you could have some bad end switches which trigger the circulator and boiler

    Show us a pic of the zone valves to assure they can be manually opened and initiate a call for heat
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ROCP
    ROCP Member Posts: 9
    Thank you hot_rod. I will try that out and let you know the outcome.
  • ROCP
    ROCP Member Posts: 9
    I will also post a picture of the zone valves. They have levers on the top that when the therm is not calling for heat the lever is steady or stiff but when calling for heat the lever moves freely.
  • Jamie Hall
    Jamie Hall Member Posts: 21,569
    Your comment on the little slider on the top moving freely when the basement zone is calling at least suggests that a) the thermostat is telling the zone valve what to do (open) and b) the zone valve is doing it (opening). However, the question then is -- does the zone valve tell the circulator and boiler what to do -- that is, run? That is done by the end switch on the zone valve, and it may not be closing properly.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ROCP
    ROCP Member Posts: 9
    Thanks Jamie

    So I have tried what hot_rod suggested and noticed that all zones except the basement zone call for heat properly. When I move the slider on all other zones it actually turns on the boiler however when I move the slider on the basement zone it does not turn on the boiler. Question, where is the end switch located?
    HVACNUT Member Posts: 5,270
    Agree with all from above.
    If the zone valve opens (the lever moves freely) and there's heat in the basement zone when the first floor thermostat is on, then it definitely seems like the end switch is faulty for the basement zone valve. Or an end switch wire isn't spliced or making contact.

    When you say "flushed", you're referring to purging the heat loops to get air out?
    Is there an air scoop or air eliminators at the boiler?

    If the only work done was purging the loops, then a faulty end switch is not related. If that is the problem.
  • ROCP
    ROCP Member Posts: 9
    Yes the unit was purged and they installed an air eliminator the same day they purged it. I forgot to mention that earlier my mistake.
  • ROCP
    ROCP Member Posts: 9
    I removed the cover to where all the wires go and all cables are tight with wire nuts and did not see any loose cables, they are all also making contact. Do I need to replace the zone valve entirely to correct this issue?
  • ROCP
    ROCP Member Posts: 9

    It appears to be a bad end switch. When I press the end switch nothing happens at all. I checked what happens with the other zones and when pressing the end switch the system starts up. Question, can I just replace the end switch or does the entire zone valve need to be replaced?
  • ROCP
    ROCP Member Posts: 9
    Hi all

    Just want to provide a quick update. First off I appreciate all the advise that was provided to me on this forum your help was greatly appreciated. The issue ended up being the end switch as was explained in the forum. I swapped out the entire zone valve and everything works as expected now. Thank you all for your help and keep up the good work.