3 - 1
Section B Body & Framework
9803/7130
Section B
3 - 1
Issue 1
Basic Operation
193150
To operate the air conditioning, the operator turns the air
conditioning switch F clockwise to the ON position and turns
the blower switch G clockwise to select a suitable blower
running speed for the ambient conditions.
Note: Switch K controls the amount of coolant supplied to a
heater coil in the air conditioning unit. This control enables
air conditioned air to be heated to supply warm, de-
humidified air to the cab in cool, humid climates.
Provided that the ambient temperature is above 0°C and the
blower switch is away from the OFF position, the air
conditioning will switch on. The compressor's
electromagnetic clutch operates, engaging the compressor
drive from the engine pulley system. The compressor A
draws in low pressure refrigerant gas from the suction line
(evaporator to compressor) and increases refrigerant
pressure through compression. Increasing pressure also
increases refrigerant temperature.
High pressure refrigerant is forced from the compressor to
the condenser B, mounted in front of the engine radiator.
Ambient air is drawn across the condenser fins by the
engine 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 C. The
receiver drier serves as a reservoir for refrigerant and also
contains a desiccant to remove moisture from the system.
Air Conditioning
R-134a Refrigerant
Due to environmental concerns, the use of ozone depleting
chlorofluorocarbons (CFCs) in air conditioning systems is
being gradually phased out.
The R-12 refrigerant used in some systems contains CFCs
and is now being replaced by a hydrofluorocarbon (HFC)
refrigerant R-134a, which does not cause ozone depletion.
The refrigerant used in the 2CX air conditioning system
is R-134a.
Air conditioning systems using R-134a refrigerant are not
compatible with systems using R-12 refrigerant. No attempt
should be made to charge R-134a systems with R-12
refrigerant.
System Operation
To maintain optimum operator comfort in warm climates or
during seasons of high ambient temperature, the air
conditioning system delivers cool, dehumidified air into the
cab. Cooling is provided by passing the warm ambient air,
together with 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 A,
condenser B, receiver drier C, expansion valve D and
evaporator coil E.
To Next Page
Loading...
Need help?
General
