I have zoned heating/AC/heat pump. My original thermostat on the wall is NOT connected to any wires, in other words it is wireless. I thought it had wires so bought the new Nest thermostat. Unfortunately when taking the original thermostat off the wall discovered it has no wires connected to furnace. Is there any way I can still hook up the Nest thermostat since there are no wires from the furnace to the original thermostat?