Last month, I had a Trane XL14c 4DCY4-UC-2 (4DCY4036A1075AA) Dual Fuel, 3 ton package unit with a BAYSEN01ATEMPA Outdoor Temperature Sensor hooked up to a TCONT402AN32DA Thermostat and have noticed that the heat pump cuts on for a while but invariably goes to stage one gas, even though the outside temperature is in the 40's and 50's. My wife keeps complaining that the air is "freezing" coming from the vents when the unit first cuts on but I keep telling her that is just a Heat Pump and she is exaggerating slightly as the air is cool, not freezing. She says when it first turns on she dreads it because it actually feels like it gets colder, then the gas turns on and it immediately warms up. It seams the gas runs more than the heat pump. My understanding of the dual fuel was that it would only switch to gas if:
a) it was too cold outside-i.e. less than 38 or so degrees.
b) the differential between the current inside temperature and desired inside temperature was large enough - thought I remembered 5 degrees?
Is my understanding correct?
Should the gas be running with the outdoor temperatures in the 40's and 50's?
How cold should the air be coming out of the vents when the heat pump is operating?
Any help, advice or knowledge anyone could offer would be greatly appreciated.