75,000 BTU Concord furnace with 2 ton heat pump.. Chromatherm Thermostat and when the heat comes on both the heat pump and gas furnace are running... How do I correct the wiring malfunction so the heat pump initially comes on and the gas furnace comes on when the pump can't keep up or in the event of an emergency??

Buy a Honeywell 8000 series T stat. It has provisions for a duel fuel system that you have . Follow the directions and it is a piece of cake to hook up.