Carrier 68G5-105 Series - 1.2.5 System Operating Controls And Components

1-8
T -312
H
L
W
O
H
G
I
HEAT
H
L
W
O
H
G
I
DEF
Down (D ecrease) Selection
Up (Increase) Selection
Fresh Air Heat Only
Cooling
Only
Vent Only
On/Off
Fan Speed
Display
Inside/Outside
Tem pe r a t ur e
Automatic Control
Defrost (Driver’s
Evap Blower)
Heat (Driver’s Evap
Coolant Valve)
Figure 1-8. System Operating Controls
(upper left hand switch panel)
1.2.5 System Operating Controls And
Components
There are five controls on the driver’s station which
affect the operation of the Carrier supplied equipment
covered by this manual. These controls include two
rocker switches, two slide switches, and the Micromate
Control Panel.
The first slide switch is the Defrost Switch (Figure 1-8).
This switch controls the driver evaporator blower motor
speed. The second slide switch is the Heat Switch
(Figure 1-8). This switch controls the driver evaporator
coolant valve. These switches are located on the
dashboard to the left of the steering wheel.
The third control is the Driver Display Panel (Figure 1-8)
which operates the Carrier Transicold microprocessor
controller , circuit breakers and relays. Modes of
operation include Vent, Heat, Cool and Auto. This
control panel is located on the dashboard with the slide
switches to the left of the steering wheel.
In the vent mode the evaporator fans are operated to
circulate air in the bus interior.
In the heat mode the heat valve and the OEM supplied
floor blower and/or boost pump are energized. The
evaporator fans operate to circulate air over the
evaporator coil and heater coil in the same manner as
the vent mode.
In the cooling mode the compressor is energized while
the evaporator and condenser fans are operated to
provide refrigeration as required. The compressor is
fitted with cylinder unloaders to match compressor
capacity to the bus requirements. Once the interior
temperature reaches the desired set point, the system
will maintain compressor operation and open the heat
valve to allow reheating of the return air . In the reheat
mode interior temperature is maintained at the desired
set point while additional dehumidification takes place.
Figure 1-9. Parcel Rack On/Off
The forth control is the rocker switch for the Parcel Rack
(Figure 1-9). This switch will de--activate the parcel rack
evaporators if the main evaporator is in operation. This
switch is located on the dashboard to the right of the
steering wheel.
The fifth control is the rocker switch for the Driver A/C
(Figure 1-10). It is located on the left side console panel
near the transmission gear selector. This switch will
activate the system to provide cooling for the driver in
the event that cooling is not called for by the Carrier
T ransicold microprocessor.