Air Conditioning

Keeping you cool


Components of the Air Conditioner System

Did you ever wonder how the A/C system works?  Let me explain it to you.

The components of the air conditioner system consist of:

  • Compressor
  • Condenser
  • Evaporator
  • Receiver/Dryer
  • Expansion valve
  • Thermostat
  • Freon
  • A/C control panel

The COMPRESSOR is driven by a belt from the main pulley at roughly the same rpm as the engine. The compressor has a clutch that rotates with the belt and activates when the A/C is turned on at the A/C CONTROL PANEL. This allows the compressor to circulate gaseous FREON to the CONDENSER dissipating the heat absorbed by the freon and turning it into a liquid state, then through the RECEIVER/DRYER. From there the freon is directed to the EXPANSION VALVE. The expansion valve controls the flow of freon into the EVAPORATOR, turning the liquid freon into a gas. In this gas state the freon circulates through the evaporator, absorbing heat from the passenger compartment, turning the freon into a liquid again.

The receiver/dryer is a canister that freon circulates through to clean and dry the freon. It contains a desiccant to dry the freon and a charcoal filter to eliminate moisture. The receiver/dryer is usually where the sightglass is and is used to view the level of freon in an air conditioner system .

The compressor is usually a multi cylinder pump that circulates freon at a constant pressure regardless of engine rpm. A clutch on the compressor allows the compressor to be disconnected from the drive pulley when the thermostat reaches a preset temperature. The compressor clutch is also deactivated under heavy loads to assure that more power is available to the engine when needed.

Freon is a substance that has properties that allow for absorption of heat. There are several different kinds of freon. New cars (94 and newer) use freon 134. This has the same properties as freon 12 but without chlorofluorocarbons or CFCs. The change was done to eliminate ozone depletion. The two types of freon should not be exchanged. Freon as a liquid is very cold…about 150 degrees below zero. The A/C system should be checked periodically for leaks. The freon does not require periodic changing. The A/C system maintains a tight seal by circulating a small amount of oil through the system to keep the seals soft. Lack of use of the A/C system causes leaks to develop as the seals dry up and crack. Therefore you should run the A/C system for at least several minutes weekly, year round.

The evaporator is located under the dash on the right side. It is a small radiator like device that circulates gaseous freon. The fan blows air through this small radiator absorbing the heat from the passenger compartment. As air passes through the evaporator, it removes moisture from the air and vents the moisture to the ground.

The expansion valve is a valve with a very small hole through which freon is forced, causing the freon to become a gas.  This gas is what circulates though the evaporator absorbing heat. The temperature of the freon circulating through the evaporator regulates the opening.

The thermostat, located inside the evaporator housing, prevents the evaporator from freezing by cycling the compressor on and off. The condenser dissipates heat absorbed by the freon. It is located in front of the radiator, and is cooled by the two radiator fans.

The A/C control panel on the dash regulates the temperature and direction of the air from the air conditioner system.

For rapid defrosting, the controls should be set for defrost, hot, recirculated air, A/C ON, fan on high. The air conditioner works best as a dehumidifier. For rapid cooling, the controls should be set for vent, cold, fresh air, A/C on, fan on high. After 5 minutes or so, reset the controls for high/low, temperature to suit, fresh air, A/C on, fan on low. The air conditioner system on a Honda vehicle is designed to cool the engine as it runs, therefore it is not necessary to turn off the A/C system when going uphill or under load. The radiator fans come on when the A/C is turned on keeping the engine cool.

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