Warm air from your house is drawn through the furnace blower and the air filter, then forced through the evaporator coil. The liquid refrigerant inside the coil boils into vapour as it absorbs heat from the air, cooling the air and making it air-conditioned.

 

The refrigerant vapour is drawn to the outdoor unit, where the compressor adds pressure and heat to the hot vapour, raising its temperature to well above the ambient outdoor temperature. The high-pressure, high-temperature compressed vapour flows into the condenser coil, where the vapour gives up its heat to the cooler outside air. This heat transfer is facilitated by the condenser fan, which draws outside air through the coil, absorbing the heat, and blowing it out the top. If you put your hand above the outdoor unit in the air flow, the temperature is warmer than the surrounding air. By removing the heat from the high-pressure high-temperature liquid, it causes the vapor refrigerant to condense into a liquid.

 

The liquid refrigerant then continues its journey back to the evaporator coil inside.

 

The last step is the high-pressure, vapour passes through a restriction right before the coil to relieve some of its pressure, further lowering the temperature to be ready to absorb more heat on the next cycle.

 

Any more questions? Just ask Eric.