I recently moved into a house with a carrier 25hcb6 2 stage heat pump and a edge thermostat that was installed shortly before I moved in. The system originally was not wired as a two stage unit and this issue was recently fixed but I have not really had the unit running at all due to the moderate temperatures we have had since the issue was fixed. Now that it is finally heating season in Atlanta I have started to use the heat pump to heat my house. I have noticed that it only stays in first stage heating for ten minutes before switching to the second stage for around 15-20 minutes and then it goes back to the first stage for around 5 minutes before shutting off each cycle. This is with the house set for 68 degrees and outdoor temperatures of around 50 degrees.
Judging by the short cycling of the unit in the summer during near design temperatures(less than 10 minute run times at 3 degrees below design temperature) it appears that my unit is extremely over-sized so I would not think that the system is undersized to heat the house at moderate temperatures. Is it normal for the heat pump to always go to the second stage for each heating cycle. I know that my first stage was set at an extremely low fan speed(around 250CFM per ton depending upon the ESP of the system),not sure if this could have anything to do with this. Also, how does the Edge thermostat decide to switch between stages and is there anyway to make it stay in first stage longer?