Tech arrived and performed diagnostics on each part and found stepper motor was not communicating causing system to pump down, tech replaced stepper motor and started system. Tech did not find any further challenges with system operations at this time. Tech did find 20x30x1 filter stopped up and replaced. System is on and operating with good temp turn around at this time. All codes have cleared from thermostat at this time. Tech set thermostat to customers desired temperature and put on permanent hold. Maintenance will need to be completed.