I am trying to get 2 Comfortmaker package units to work correctly. Here is the issues, on both units I have a low suction and a high head pressure. They cool ok on a day its not real hot but on a hot day they are not doing so good. They are helping cool a kitchen at a restaurant and have been for about 10 years. I have proper airflow clean filters and both coils are clean. When I have the guages on either unit the high side pressure is fluttering bad and is way high. I do not see a metering device. Can somebody give me some insight.