RESSAC A/C tech arrived at commercial retail store to inspect a Trane Package Unit. Technician got on the roof to repair communication loss of the unit with the thermostat. He found a wiring connection between Circuit one controlling the contactor had been switched to operate the stage 2 compressor. Tech fixed the wiring issue and called the HVAC controls company managing the unit to ensure proper unit communication. The unit was restored to proper operation.
