This won't be easy. I found a gizmo that uses a terminal "K".
http://www.forwardthinking.honeywell...69_2065efs.pdf
First of all, with heat pumps, the outsde unit does operate in the winter, but not when the temperature is below 40 F or definitely below freezing.
In reality:
Balance Point:
An outdoor temperature, usually between 30° F and 45° F, at which a heat pump's output exactly equals the heating needs of the home. Below the balance point, supplementary electric resistance heat is needed to maintain indoor comfort.
Emergency Heat (Supplementary Electric Heat) - The back up electric heat built into a heat pump system. The same as an auxiliary heater, except it is used exclusively as the heat source when the heat pump needs repair.
Heat pumps are wired animals and you have to determine a few things.
Hey could be a single stage heat ump with emergency heat. This puts the burden of switching modes on the homeowner. When the outside temp is above the balance point, the homeowner switches to emergency heat.
Dual stage heat pumps will use the heat pump and when the heat pump can't really produe enough heat, aux heat runs in addition to the heat pump. Sensors wired to some thermostats can force the aux heat to run when the out side temp is below the balance point. Or you can force it to run in stage 2, when your in emergency heat mode.
Dual fuel systems adds additional complications. In these systems, the heat pump and the aux heat cannot run at the same time. Ex ample. An eectric furnace and a heat pump or a gas furnace and a heat pump.
Your descriptions are bugging me a bit and some condos use variations of commercial systems. They could use fan coils with one or two pipes which are essentially chilled water systems.
You might have a central boiler and your own AC unit. These systems would not happen in a home.
I find it odd, when you said that the AC is operating in the winter. Not sure you mean blowing cold air or the outside unit is running.
Heat pumps also nned to run in the AC mode when calling for heat when the system detects that the outside coils have to defrost.
We have a lot of possible complications to sort out:
1. What kind of system do you really have
1a Single stage heat pump with emergency heat
1b. Dual stage heat pump with aux heat
1c Do you really have a heat pump at all?
2. The K terminal that no one seems to know about
2a. How many wires were at the thermostat
2a1. What was the terminal designations
3. Are their the conventional heat pump terminals in the air handler. C, W, Y, O/B, G; Separate O & B
4. Is there a gizmo in the air handler that took the conventional terminals and added a K terminal, say becaue it was do difficult to retrofit to add AC to the existing Codo at one time.
5. Did you have separate control of the FAN mode with the old stat. I suspect not, because of the K terminal.
I have are questions than answers.
In fancy stats such as the Honeywell vision pro series, you can put a sensor in the outside unit that measures the outside temp and the balance point is then selected in the thermostat.
There can be a lot of things going on here.
Most important questions:
1. # of wires at the old stat total and connected.
2. What they were connected to?
3.What terminals are at the air handler?
4. Is heat included in the condo fee?
Any info about the air handler, old stat and outside unit at all.
Condos cause all sorts of grief. They are sometimes a cross between a hotel system and a residential system. Manufactured homes may also set the mode of the system at the furnace, so can condos when they use a 1 pipe system..
I'm not sure what kind of help I can be.
Obviosly the mode is not right when it's set to heat only and you have AC.