Performed CMA full service on 4 rooftop package units. There are a total of 7 on site, but only 4 are currently operating. Of the systems serviced today, RTU 3 is the only system with any major challenges. RTU 3 - compressor 2 on this system is shorted to ground. System is currently operating at half capacity. This will be apparent on days with prolonged heating or cooling needs. At time of testing, weather is mild and delta t is only getting to between 11-13 degrees. This is not enough temperature changeover to cope with high demand. Field supervisors office has an active proposal on this system and they are awaiting decision. All other systems tested are heating and cooling properly. No other challenges present. Note - RTUs 1,3 and 5 are not equipped with auxiliary back up heat. Filters - all filters changed and old ones disposed of.