I have a one year old Ducane Heat Pump. The A/C seemed to work fine this summer but now that heat is required I cannot get the unit to heat except via Auxiliary heat. I upgraded the thermostat to a Honeywell programmable to no avail. When the temp drops the thermostat calls for heat but the HP does not kick on. The air handler runs but the compressor does not run. Once the temp drops two degrees then the electric (aux heat) runs and brings the temp back to the temp set on the thermostat. If I reset the system by cycling the two circuit breakers on the unit the HP will work (compressor fan engages) for about five minutes before it kicks off and then I am back to Aux heat only. The Ducane is model 4HP16LT36P-1 and serial number is 1610C15460. I had the control module (not sure the exact name) on the HP replaced by a HVAC repairman and it seemed to work properly for about 24 hours. Now it is back to the same routine. The fault that is triggered is "high pressure" but the HVAC repairman said all of the pressures were perfect..