Had a new Trane system installed about 2 yrs ago. XL18i, TAM7, and Nexia 624. The original Nexia died about a year ago and a new one installed. Has been working ok since but just recently it seems to be powering off at random times, only to come back to life and run the A/C for a short time. Then it goes dead again and the A/C shuts off. I'm thinking the thermostat is on its way to the scrap heap again. Being a Sunday, reluctant to call the installer if it could be something minor. Also wondering if all these short cycles are damaging the outside unit. If the thermostat is on the way out, wondering if there is a different model that is more reliable for this setup. Don't need the fancy wifi thing.