I have a trane heat pump with a hunter thermostat,so for instance I set my thermo too come at 69 or whatever temp it will blow heat the first time like it should. But once it goes off and later comes back on then it always blow cool air. Ican shut unit off raise temp a couple degree and heat blows but once it reaches temp and cuts off and later comes back on then cool air blows again any one knows what maybe be the problem it gets a little cold here a night yhanks and advance

Next time this occurs, have a peep at the outdoor unit to see if it is running, feel the larger refrigerant line (carefully, could be hot), post back.