An air conditioner diagram usually shows the four main parts: the evaporator, compressor, condenser and the expansion valve. The evaporator and the condenser fans may also be included. Some diagrams also indicate the movement of air by directional arrows or with a simplified drawing of the lines connecting the components.
Air conditioners have a cold side and a hot side. The evaporator, which is made up of coils that are filled with refrigerant, is on the cold side. The evaporator's fan blows across the coils, pushing cold air into the structure.
The condenser and its fan are on the hot side. The compressor is right in the middle. When the compressor pressurizes the refrigerant, it changes it from a gas into a liquid, producing heat. The fan blows the hot air given off by the compressor to the outside. The liquid refrigerant then goes to the condenser.
The condenser is connected to the evaporator by the expansion valve. This valve governs the liquid refrigerant's rate of flow into the evaporator. The drop in pressure in the evaporator turns the refrigerant back to a gas, chilling the evaporator coils. The gas goes back to the compressor, and it all begins again.