I recently rewired two thermostats into one Honeywell RTH9580WF1005 Wifi Thermostat. I ran a new wire and hooked up R and W to the oil boiler and Rc, C, G, and Y to the Goodman air handler. The Y is wired directly to the condenser as the control board does not have a Y in the harness. The other wire from the condenser goes to C on the control board.
When I turn on the thermostat circuit breaker, the condenser/compressor immediately starts up. I checked the contact outside and it appears to be working smoothly. With the power on, the contact is depressed. When the power is off, the contact is open and I can press it easily to start it. It seems to me that the Y wire is always energized and thus the condenser won't turn off.
I just replaced the control board thinking that there was a short in the controllers. However, the issue still remains so the board is not at fault.
How should Y be wired when there is no place for it on the control board? How should the thermostat be wired to control two separate systems? Should R and Rc be jumped or not? How can I test the voltage of the wires to verify it was done correctly?