Heating and Air Conditioning: Description and Operation

Automatic Climate Control System Components:

PURPOSE

The Automatic Climate Control (ACC) system combines various heating, air conditioning, and ventilation components, in order to automatically maintain passenger comfort in all weather conditions.


CONSTRUCTION

The ACC system consists of:

^ Conventional type air conditioning system
^ Integrated blend-air heater and evaporator housing with vacuum actuated air distribution
^ Combination control unit/push-button switch panel
^ Various switches, sensors, and vacuum components.

OPERATION

Temperature regulation, quantity, and distribution of cooling and heating air is automatically adapted to passenger desire via the ACC push-button control panel.
The interior temperature is controlled by the:

^ Airflow directed through the integrated heating and air conditioning housing
^ The mono valve On/Off ratio, (volume of hot water through the heat exchanger)
^ Refrigerant system activation.

Heating And Fresh Air Flow:

If there is a temperature difference between the in-car sensor and the preset value indicated on the temp wheel (e.g. to cold by 10°F) during automatic control, the electronic control unit will adjust the frequency of the mono (heater) valve to allow more hot water through the heat exchanger. When the desired temperature is attained, the control unit, via resistance input from the interior temperature sensor and the heater temperature sensor, corrects the mono valve frequency for level temperature output.
If heating is not required, the mono valve is powered closed, and the diverter and recirculation flaps are positioned as needed by the ACC control unit. Additionally, the temperature of the evaporator is continuously compared against the desired temperature; the A/C compressor is switched "ON", if required.