Complete 2 Systems worked on Both Systems US and DS. US Carrier Straight A/C: HO stated system was freezing up. Found system low in refrigerant. HO authorized ro add refrigerant. Added 2 lbs of R22 and a can of leak stop. Checked pressures. System is running great at this time. DS Carrier Gas Pak Straight A/C: HO stated that he just wanted his ds system checked out and make sure is was running properly. Cycled system. Monitored blower motor, compressor and cfm. Checked pressures. System is running great at this time.