The condenser functions as a heat exchanger for the air conditioning system. It’s located in front of the radiator and constructed of tubing surrounded by cooling fins. It releases heat into the outside air passing through these fins. An automotive air conditioning system receives heat energy from the evaporator located in the passenger’s cabin and releases it through the condenser to the outside air.
The condenser receives high temperature high pressure vapor from the compressor and converts it to high pressure liquid through the process of condensation. As air passes through its fins, the heat contained in the refrigerant is passed through the condenser fins and into the atmosphere.
The purpose of the condenser is to release heat and change the state of the refrigerant from vapor to liquid. Vapor enters at the top of the condenser and pressure forces it down to the outlet located at its base. As the refrigerant passes through, it cools and condensation occurs. Because of this, the inlet at the top should be hotter to the touch than the outlet at the bottom. Condensation leaves the top portion of the condenser filled with vapor and the lower portion filled with liquid. This liquid refrigerant is then passed onto the receiver drier or metering device.
A non-contact infrared thermometer is often used to check for restrictions. The conversion in temperature from the top to the bottom should be smooth and even. Any sudden changes in temperature indicate a restriction in the condenser. A restriction in an automotive air conditioning condenser results in high high side discharge pressures.