The compressor 1 draws in low pressure refrigerant gas from
the suction line (evaporator to compressor) and increases
refrigerant pressure through compression. This process also
increases the refrigerant temperature.
High pressure refrigerant is forced from the compressor to
the condenser 2, which is mounted on the radiator on the
side of the engine. Ambient air is drawn across the
condenser by the engine-driven cooling fan. In the
condenser, the refrigerant changes state to a high pressure,
high temperature liquid but with a lower heat content.
The refrigerant passes through the receiver drier 3, which
contains a desiccant to remove moisture from the system.
The receiver drier serves as a reservoir for refrigerant and
also includes a filter to remove foreign particles from the
system.
Operation
To maintain optimum operator comfort in warm climates or
during seasons of high ambient temperature, the air
conditioning system recirculates, clean, dehumidified air into
the cab. Cooling is provided by passing the recirculated air,
over an evaporator coil in the air conditioning unit.
The air conditioning system is a closed circuit through which
the refrigerant is circulated, its state changing from gas to
liquid and back to gas again, as it is forced through the
system.
The major components of the system are the compressor 1,
condenser 2, receiver drier 3, expansion valve 4 and
evaporator coil 5.
Heater/Air Conditioning Controls
Located on the Left side of the Rear Panel, the heater/air
conditioning controls are used in conjunction with the heater
fan controls.
Heater Controls
A Ventilation control - with the control turned fully
clockwise, air to the heater is taken directly from outside
the cab. With the control turned fully anti-clockwise, air to
the heater is drawn from inside the cab and re-circulated.
Settings between the two extremes result in varying
mixtures of fresh and re-circulated air.
B Air flow control - with the control turned fully anti-
clockwise, air flow from the heater is directed into the
body of the cab. With the control turned fully clockwise
air flow from the heater is directed at the windscreen.
Settings between the two extremes result in degrees of
partial flow to the cab and to the windscreen.
C Heat control - with the control turned fully clockwise, air
flow from the heater is hot. With the control turned fully
anti-clockwise air flow from the heater is cool. Settings
between the two extremes result in varying temperatures.
Air Conditioning Controls (if fitted)
D Air conditioning ON/OFF control - this two position rocker
switch is used to select or deselect the facility. When the
‘snow flake’ icon is pressed to switch air conditioning ON,
the switch illuminates.
Air conditioning system power is generated from the engine,
via an electromagnetic clutch to the compressor. Three
switches, connected in series, are included in the clutch
supply line, all must be closed for the clutch and therefore
the air conditioning system to operate.
12 - 2
Section B
Body & Framework
9803/6400
Section B
12 - 2
Issue 1
Air Conditioning
AA
BB
CC
DD
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