Answer

First of all the leak must be fixed. You have to connect a set of gauges to the unit, one line to the high side and one to the low side. If there is pressure in the system now it must be captured before you proceed. After assuring no freon in the system you can evacuate the system with the pump. You will reach a point where the vacuum on the gauge stops increasing. At this point close both valves on the gauges and turn off the pump. You MUST maintain this vacuum for some period of time. If the vacuum decreases at all there is a leak. 1.15 kg is the amount of R22 to fully chage the system. If you have a scale you can weigh the container of freon before you start to refill the system and when you have reduced the weight by 1.15 kg you should be just right. Always make sure you bleed the "air" out of the line when you connect the freon tank to the gauges. With the valves closed and the tank valve opened crack the line to the tank at the gauges letting the air out. Retighten and your system is sealed. With the unit turned off open the valve going to the low pressure side of the unit, the bigger of the 2 lines. Allow gas to enter the system and watch the pressure rise on the gauges. When pressure is established in the system it will turn on. When the tank pressure and system pressure are the same start the system and gas will be drawn into the system on the low pressure side. When you get near 1.15 kg installed in the system it should be cooling well. If you install too much freon it will hurt the cooling capability of the system. If you don't have a scale available check the temp of the air blowing out of the vents of the indoor unit. It should get down below 60 F when it is charged fully. When the temp stops dropping you have the most cooling and it is charged. Make note of the high pressure side pressure at this time. Turn off the valves and the tank valve. Remove the lines carefully from the ports on the unit. If you lose cooling again you haven't gotten it sealed well. Connect the gauges, start the unit and observe the high pressure side pressure. If it has dropped there is a leak. If it is the same it's another problem.