Heating and Air Conditioning: Application and ID

Features And Controls (MCC-ECC):





MCC stands for "Manual Climate Control". ECC stands for "Electronic Climate Control".

MCC - control panel:
- The A/C and recirculation switches have indicator lights which come on when the functions are selected.
- Fan speed is controlled by a sliding control with four speed settings and an 'off' position.

ECC - control panel:
- The temperature controls are fitted with temperature scales and 'max' and 'min' settings.
- Automatic stepless control of fan speed with the fan speed control in the "aut" setting. Other settings give manual stepless control of fan speed, with an 'off' position.
- Automatic air distribution control with the air distribution control in the "aut" setting. Other settings give manual stepless control.
- With the "rec" switch off (indicator light off), the ECC control unit will select recirculation in some cases if this will accelerate cooling.
- The "ac off" switch is used to switch the AC system off (indicator light off).

Climate Control Units:





The same climate control unit is used in both the MCC and ECC systems. The image shows the control units and components used in each case.

MCC:
- Fan resistance (1).
- Max. fan speed relay (2).
- A/C relay (13).
- The recirculation motor (3) controls the recirculation damper in three positions: open, closed or 30% recirculation at max. fan speed.

ECC:
- Damper motor, driver's side (16).
- Damper motor passenger side (17).
- Damper motor, recirculation (18). Unlike the MCC recirculation motor; this has stepless control.
- Damper motor, ventilation (14).
- Damper motor, floor defroster (15).
- Power stage (11) controls fan (12) speed. As the power stage generates a certain amount of heat, the cooling fins face inwards towards the airflow.
- A/C relay (13).

Temperature Dampers:





Two temperature dampers, one for the driver's side (5) and one for the passenger side (6), are controlled by cables in MCC systems and by damper motors in ECC systems. This can be used to give two airflows at different temperatures, depending on the temperature control settings.

Air Distribution Dampers:





There are three pairs of air distribution dampers. The ventilation dampers (1) are mounted on the same spindle as the side defroster dampers (2), while the second spindle carries the floor/defroster dampers (3). The dampers are operated manually by cables from the air distribution control in MCC systems and by damper motors in ECC systems.