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Taco Zone Valve

Hi, I have 3 taco zone valves in my house. I've just noticed when the heat turns on upstairs I am also seeing my downstairs heat turn on even thought it's not calling for it. This morning I also realized the same this was happening vice-versa. When the downstairs heat kicked on I was getting heat upstairs even though it wasn't calling for it. The 3rd zone stayed off (like it should) One of the zone heads was replaced last year, but I'm wondering if the other or both zone heads need to be replaced? Any help would be appreciated.


  • Zman
    Zman Member Posts: 7,588
    I would turn on the t-stats one at a time and verify that they are operating the corresponding zone valve. Incorrect wiring is a possibility. If that is not the case, you may have one valve that is stuck open so that zone heats when any other zone heats.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    +1 to @Zman
    Also, when you say "...I am also seeing my downstairs heat turn on..." are you looking at a zone panel and seeing lights, or do you just feel heat?

    There was an error rendering this rich post.

  • heatguy92
    heatguy92 Member Posts: 2
    Hi Steve, I'm feeling the heat at the baseboard
  • Joe Mattiello
    Joe Mattiello Member Posts: 707
    I was reading your comments about the downstairs zone heating when 1st floor has demand. That would happen if the zonevalve was stuck open, or the thermostat was stuck closed. You can take one of the thermostat wires off terminal 1 on downstairs zonevalve, and see if it resolves issue. If not, you can take the actuator off valve, and temporarily replace it with your third zone valve actuator, to see if that resolves the issue.

    You mentioned the issue is duplicated when downstairs has a heat demand, and upstairs gets hot too, but I'm not sure why it would happen in reverse unless that valve is faulty too.
    Hopefully, this helps you resolve your issue.

    I'm available to discuss further, if you would like to call Taco at 401-942-8000; ask for Tech support.

    Joe Mattiello
    N. E. Regional Manger, Commercial Products
    Taco Comfort Solutions
  • dford1013
    dford1013 Member Posts: 7
    Hi guys, I have 2 zones in my house that have taco zone valves. Getting overheat upstairs like my valve won't close. Also I have power on terminals 2 and 3 when the thermostats are not calling for heat. Is this normal? I have 1 taco gold, 1 green for baseboard heat and a Honeywell V8043E1012 for my indirect water tank. My controller is a hydrostat 3150. Could the ball in the valve be getting stuck or could this be a wiring problem? When i turn up my thermostat, terminals 1 and 2 get power but when there is no call for heat 2 and 3 have power and the valve lets hot water through. Confused!!
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,646
    What happens when you disconnect wires 1,2,and 3?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Alan (California Radiant) Forbes
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab