Basic Principles

The manual climate control system heats and/or cools the vehicle depending on the function selector switch position and the temperature selected.
- The function selector switch position determines heating or cooling and air distribution.
- The temperature control setting determines the air temperature.
- The heater blower motor switch varies the blower motor speed.

PRINCIPLES OF OPERATION
There are four main principles involved with the basic theory of operation:
- Heat transfer
- Latent heat of vaporization
- Relative humidity
- Effects of pressure

Heat Transfer
If two substances of different temperature are placed near each other, the heat in the warmer substance will transfer to the colder substance.


Latent Heat Of Vaporization
When a liquid boils (changes to gas) it absorbs heat without raising the temperature of the resulting gas. When the gas condenses (changes back to a liquid), it gives off heat without lowering the temperature of the resulting liquid.


Relative Humidity
The amount of moisture (water vapor content) that the air can hold is directly related to the air temperature. The more heat there is in the air, the more moisture the air can hold. The lower the moisture content in the air, the more comfortable you feel. Removing the moisture from the air lowers its relative humidity and improves personal comfort.


Effects Of Pressure On Boiling Or Condensation
As the pressure is increased on a liquid, the temperature at which the liquid boils (changes to gas) also increases. Conversely, when the pressure on a liquid is reduced, its boiling point is also reduced. When in the gas state, an increase in pressure causes an increase in temperature, while a decrease in pressure will decrease the temperature of the gas.