A car AC service typically includes a variety of maintenance tasks to ensure that the air conditioning system in a vehicle is functioning properly. This can involve checking the refrigerant levels, inspecting for leaks, testing the compressor, cleaning or replacing the cabin air filter, and ensuring that the system is blowing cold air efficiently. Additionally, the service may involve checking the overall performance of the AC system and making any necessary repairs or adjustments to keep it running smoothly.
Parts of a Car Air Conditioner
- Compressor
- Condenser
- Thermal expansion tube / orifice valve
- Evaporator
- Accumulator or receiver/drier
Compressor
The compressor is a simple pump that pushes the refrigerant through the loop. As it pumps the refrigerant, which at this point is a gas, it also compresses it (hence the name) and causes it to be under high pressure. The high pressure also causes the refrigerant to become very hot— hotter than the summer air outside.
Condenser
The hot, high-pressure refrigerant flows through the high-pressure tube to the condenser. The condenser is in front of the car’s radiator, looks like the radiator, and basically does the same thing as the radiator: it uses the air flowing through it to cool the refrigerant. The hot refrigerant, which is normally a gas, condenses into a liquid as it cools (which is why it’s called a “condenser”).
Thermal Expansion Tube / Orifice Valve
The now-liquid refrigerant flows through high-pressure tubing back toward your car’s dashboard, where it passes through a small valve. Depending on your car, this valve is called either a thermal expansion valve or an orifice tube. It then changes back to a low-pressure gas.
The valve allows only a small amount of refrigerant through at a time, and also relieves the pressure created by the compressor. A funny thing happens when you suddenly reduce the pressure: the refrigerant becomes very cold.
Evaporator
The cold, low-pressure refrigerant then goes into the evaporator, which is a radiator much like the condenser and is located in your dash. But since the refrigerant is cold now, it’s the air that is cooled by the radiator, rather than the radiator being cooled by the air. An electric blower fan pushes the cold air through the vents and into the passenger cabin.
At low pressures, the R-134a refrigerant used in most cars has a boiling point of 15 degrees below zero. So, the hot summer air causes it to quickly evaporate back into a gas (which is why this parts called the “evaporator”). As it evaporates, it absorbs heat from the air passing through; without that heat, the air becomes comfortably cool.
Accumulator or Receiver/Drier
Every car A/C system will also have either an accumulator or a receiver/drier. A receiver/drier will be located after the condenser, while an accumulator will be after the evaporator. Whichever device your car has, its function is to filter the refrigerant and absorb any moisture that might be in the system.
After completing the loop, the refrigerant is then sucked back into the compressor through the low-pressure tube, starting the cycle all over again.