Upon arrival I went to location and informed receptionist I was here to get unit information and performed maintenece on units. When going up to roof I was approached by building manager who opened up sprinkler room where roof ladder was located. He informed me that we will need to call him at least one day before performing maintenece so he can give us access, express care does not have key. Wrote down Model, Serial, Filter sizes and belt sizes. Then went to supply house to pick up filters and belts. Returned and performed maintenece. Replaced all filters and belts. Inspected heat exchangers. Cleaned burners and cleaned flame sensors. Checked contactors and capacitors. Tightened all electrical connections. Ran heat on all units. Checked amp draw and heat rise. Let systems satisfy thermostats. All units are operating normal.