Arrived on site and checked in with MOD. Performed full cooling maintenance with filter change on both Rooftop package units and all walk in equipment with two condensers and six evaporators. Cleaned all condenser coils, recorded pressures, amps draws, electrical inspection, and tested all motors. Found package unit 2 on roof nearly void of refrigerant and off on low pressure safety. Located several leaks on evaporator coil U bends. Will quote to replace evaporator coil and recharge with refrigerant. System will remain down until repairs can be made. Found both condensers for walk in equipment to have issues. Beer side equipment has frozen lines due to being low on refrigerant. Located leak on liquid line service valve. Found Teflon tape on threads from previous work performed by different company. This will not work for refrigerant and is not a correct fix by any means. Compressor also has audible rattle noise while running indicating internal damage from operating this way for extend