Table of Contents
Advertisement
4-7 Inn4o5]
AUTOMATIC AIR CONDITIO NING SYSTEM
5. EVAPORATOR ASSEMBLY
The evaporator assembly is mainly composed of an
evaporator, expansion valve, and casing .
Fig. 33
1) Evaporator
The low pressure and low temperature refrigerant
changed into mist in the expansion valve is evaporated
in the evaporator, and this evaporation causes the
evaporator temperature to drop . The air is delivered by
the blower fan, and cooled down as it flows through the
evaporator fins . The cool air then blows out of the grille
after passing through the heater unit .
Cool air
i
II'
. Warm air
i
Refrigerant flow
C4-396
Fig . 34
6. EXPANSION VALVE
The expansion valve is attached to the evaporator inlet.
It converts high pressure liquid refrigerant which comes
from the liquid tank to misty, low pressure refrigerant,
and delivers to the evaporator . Being at low pressure
and low temperature, the liquid refrigerant evaporates
in the evaporator removing heat from the compartment .
It automatically controls the flow rate of refrigerant to
obtain the necessary cooling ability required by the
fluctuating heat load .
The expansion valve is composed of a sensing bulb
with a capillary tube that senses the temperature at the
evaporator outlet, an equalizer that transmits the pres-
sure of the refrigerant in the evaporator to the dia-
phragm and other parts such as the spring, ball and
diaphragm.
External
Diaphragm
Capillary tube
pressure
Upper chamber
equalizing
tube
Temperature
sensing
i
Lower
chamber
Ball valve
Refrigerant
outlet
`Ball seat
Adjusting screw
t
Spring
Refrigerant inlet
C4-397
Fig. 35
16
Advertisement
Table of Contents
Troubleshooting
