I arrived for a new customer summer service tune up. I first spoke with the homeowner and found that the system will run and cool but is struggling at times. I inspected the system and found the condenser coil to be completely stopped up. I also found the suction line to have a minimal amount of ice on the line. I inspected the indoor system and found it to be clean and in normal working condition. I then inspected the duct work and checked the systems air temperature and duct work. I found the ductwork under the home to have a lot of debris in the duct work and to have sand in the system. I recommended to get thunder duct out to see if they can fix the duct work in place. This is a flat roof home and can’t have a system installed in the attic. I then cleaned the condenser and cycled the system on with no filters installed in the system. I found the system to start to work normally with better refrigerant charge readings. I suspect with the poor supply and return duct along with the di