Hi all,

I need advise from the pros to get this annoying problem resolved.
I have gotten a brand new Trane XR17 with XV80 Gas Furnace that was installed less than three months ago through a very reputable Trane factory authorized contractor. A few weeks ago the pressure transducer is replaced. However a similar problem still exist whenever the system is switched from aux heat to heat pump or after the defrost cycle. The contractor have checked all of the sensors but couldn't find any anomaly. They'll be asking about it Trane but haven't heard back from the yet and as the weather gets colder the problems becomes more then a nuisance.

the problem occurs when the thermostat switches from aux heat to heat pump and the compressor is going short cycling 4-5 times in a minute and calls the defrost cycle for no reason because there is no ice or frost build up on the coil. The defrost cycle goes like 10-12 minutes and after the defrost cycle sometimes compressor goes two or three on-off cycle in two minutes and gets stabilized and keep working normal or it repeats the same behaviors again and gets stabilized after the second defrost cycle. The table below shows the duration of each on and off cycle. It took two defrost cycles before it to be stabilized yesterday.

I need some guidance from the pros in order to get this resolved without loosing time and wasting more energy. It is a big discomfort because during the on-off cycles the blower still blowing and unnecessary defrost cycle also causes cold air to get blown in so that in 30-45 minutes temperatures drops 2-3 degrees for no reason. I'm also afraid of that this very short cycles would ruin the life span of the compressor. Any help on this will be much appreciated

Thermostat comp state duration-mm:ss
aux heat off
heat on 1:30
off 0:30
on 0:09
off 0:30
on 0:08
off 0:09
on 0:05 stopped and the reversing valve is switched to cooling
off 0:30
heat/defrost- on 11:30
off 0:30
heat on 1:12
off 2:46
on 0:08
off 0:09
on 0:09
off 0:08
on 0:12
off 0:07
on 10:41 stopped and the reversing valve is switched to cooling
off 0:30
heat/defrost- on 6:43
off 0:30 Inside temperature dropped by 2 degrees during this period of time
heat on 2:00:00 heat pump kept working for two hours or so and the temperature rised by 3 degrees