Our home has 2 HVAC units recently it we made the decision to upgrade to new ecobee thermostats. We did not have a c wire so we followed the PEC installation instructions. Our downstairs thermostat works great with new install however our upstairs one stopped working after about 30 minutes. We first ruled out a problem with the thermostat it works so that’s not the problem. I thought maybe it was the wiring so I rewired to change the HVAC wiring from a 4 wire to a 5 wire but still no luck. It is a Payne unit and I cannot see any fuses at the disconnect. Any advice would be appreciated.