Lack of coolant (Freon) is a very common reason behind AC not cooling problem. The coolant circulates through the evaporator coils and cools the air flowing over it and eventually sends cool air into the room. So when the level of this coolant becomes insufficient, the AC fails to cool. In many cases the coolant leaks from the unit and AC stops cooling. An AC repair professional will be able to accurately determine if the refrigerant level is just right in the cooling coils.
The PRO accurately determine the coolant level in the AC unit using a pressure gauge. If the level of gas, also called refrigerant is found below the normal PRO suggests a refill or top-up as per requirement.
To start the coolant recharge, first the AC unit is shut down. Thereafter the gauge hoses are attached to the pressure port of AC unit. The AC unit is then turned on and allowed to run for 10 min so that it can reach a stable state of operation. Following it the valves of the refrigerant container (with container in the upright position) is connected to the AC unit. Now the AC unit is ready to draw coolant.