Mystery circuit - between air handler and thermostat. What could it be???
I'm trying to come up with some possible theories of what kind of circuits could exist between a thermostat wire and air handler??
- forced air electric, 2 zones
- Zone 1 is main house
- Zone 2 is wing of house controlled by a separate thermostat that actuates a damper to redirect air handler output to that wing of the house.
Zone 2 works fine, but when tracing the thermostat wiring for Zone 1 there appears to be some kind of circuit in the thermostat wiring somewhere well outside of the air handler. Whatever this circuit is, it's not easily accessible/identifiable. The thermostat wiring runs right alongside zone 1's hot air outlet duct.
(ie With Zone 1 thermostat wiring disconnected at AH and Thermo I measure 2 ohms red to red but 185 ohms white to white. That suggest possibly a relay coil???)
What possible circuits could be in line between a thermostat and air handler. Maybe a second damper?? What else is common??