Under standard installation, which was performed by the professional, filling airand no need. A split system is filled with freon, which is located in the outdoor unit in a liquid state. But if the installation is done poorly or unprofessionally, filling airand can not be avoided. Freon evaporate as a result of poorly expander connection pipe in the refrigerant circuit. A gas leak could happen one month after installation. Air will slowly cool the room, and the outer block will appear frost. These signs will indicate that air conditioning needs refilling freon.Filling split systems are necessary and after the repair of equipment or the refrigerant tube. Of course, during operation of the air conditioningand there is a natural gas leak, but this leak is quite small. It reaches 6-8 percent per year. Therefore, if there were no breakdowns of the air conditioningand it must be refilled at least every two years. If this is not done, the a / C system freon level is below the permissible value, and this will reduce the lifetime of the appliance. The compressor will overheat and burn up, and you will need to repair the split system, which will cost much more than its refill. And then the question arises: how to determine if you need a refill air conditioningbut? This can be done without special instruments and devices. Lack of freon is the reduction of the intensity of the cooling or heating of the air and the appearance of ice and frost on the outside unit. Once the owner of the air conditioningand noticed one of the signs, he must contact the service center to the system refueled. The cost of refueling depends on the amount of gas which has evaporated from its brand. For that use freon R-22, R-407C, R-410A. The safest is considered to be the last of these. It does not destroy the ozone layer of the atmosphere and safe for human health.