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Boiler return line - ghost flow

Jonn2018 Member Posts: 29
edited December 2019 in Thermostats and Controls
Hi all have a bit of a strange hearing issue going on. Seems when Zone 1 is on zone 2 gets very hot. However when Zone 2 is on zone 1 does not get hot at all. The system has taco zone valves the guts for zone 2 were changed out thinking it was stuck in open position but problem continued. Also zone 1 and 2 have separate supply lines and zone valves. But only one return line as shown in the circle in the drawing. So I think we have a “ghost flow”. I think zone 1 return instead of flowing to the basement reverse flows into zone 2.


  • Ironman
    Ironman Member Posts: 7,352
    How about some pics of the boiler that include its near piping and the ZVs?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    HVACNUT Member Posts: 5,756
    You replaced the zone valve "guts". Does that mean the actuator head?
    You probably need to replace the valve insert. Easy enough.
  • Jonn2018
    Jonn2018 Member Posts: 29
    Ironman I’ll post the pics when I get home tonight.

    HVACnut yes what we replace was the zone 2 internals the electrical part we knew was not the culprit.
  • Jonn2018
    Jonn2018 Member Posts: 29
    Attached are additional boiler pics of the supply and return piping

  • HomerJSmith
    HomerJSmith Member Posts: 2,406
    Could there be a wiring mixup?
  • Jonn2018
    Jonn2018 Member Posts: 29
    From what I saw the wiring looks fine. As far the the Honeywell valves goes, each zone valve turns on and off when it’s called.
  • Jonn2018
    Jonn2018 Member Posts: 29
    edited December 2019
    Modified pics