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Thermostats vs Zoning panel?

DIY noob here -- thanks in advance for the education!

I just moved into a new home with three thermostats. 1, 2, and 3 below.

Looking at the zoning panel in the basement...

I'm confused by two things:
(1) I have three thermostats that seem to be connected but only 2 parts of the zoning panel seem connected. I haven't proved to myself that the third thermostat does anything, though it's strange that the previous owners would have had it connected and battery-powered if it wasn't in service. Also why would the front of the zoning panel show green lights for three zones if there's nothing connected to the third?
(2) The color wires going into the zoning panel differ from those I see at the two thermostats. I do have a "Honeywell Equipment Interface Module" just to right of the panel in the picture. Could it be intervening for the two thermostats that are connected to zones so the wires I see at the zoning panel aren't the same as at the thermostat? But at least the wires leading to the zone 1 thermostat coming from the black tube don't seem to go thru the equipment module.



    HVACNUT Member Posts: 5,828
    Can you post a pic of the system that has the zone dampers? Is it a furnace with A/C or and air handler with a hot water heat coil being fed from a boiler?
    The zone 3 green light will always be on. Dont worry about it.
    Zone 1 looks like its connected to the EIM, if that wire loops down, then back up.
    Zone 1 also looks like it controls two dampers.
    Do you have a boiler?
    Do you have another heat/air conditioning system?
    How many outdoor A/C condenser units?
    Thermostat 1 has a jumper between Rc and Rh so there's possibly an isolation relay somewhere.
    Thermostat 3 has separate Rc and Rh connections so Rh and W would normally go to TT or RW in a heat zone control relay board at a boiler.
  • discodave
    discodave Member Posts: 2
    Thanks for the response!

    This is the forced-air system with an oil-fueled furnace and single A/C condenser unit. There's no other system in the house. Here are some pictures zooming out from the panel to get the furnace and fan system:

    Does that help clarify things a bit?
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    I think they either combined 2 zones, or left the one zone disconnected, and permanently opened that zone damper. Can’t tell without tracing the wires.

    I’ll have to admit I’d never seen a filter installed and hanging in the air like that. You’re not even getting the full 20x20 benefit of the filter media.

    Barometric damper shouldn’t be on a tee, just a minor point.