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62-11039
2.3.6 Transducers and Sensors
a. Compressor Suction Pressure Transducer
(CSP)
Provides micro with suction pressure information to be
displayed, recorded in the data recorder and used to
control the refrigeration system. It cannot be calibrated.
It is located near the oil pump on the compressor.
b. Compressor Discharge Pressure Transducer (CDP)
Provides micro with discharge pressure information to
be displayed, recorded in the data recorder and used to
control the refrigeration system. It can be calibrated. It is
located on the center cylinder head of the compressor.
c. Compressor Discharge Temperature Sensor
Transducer (CDT)
Provides micro with discharge temperature information
to be displayed, recorded in the data recorder and used
to control the refrigeration system. It is located on the
center cylinder head of the compressor.
d. Compressor Suction Modulation Valve (CSMV)
The CSMV opens and closes as required for capacity
control of the refrigeration system cooling cycle. It is
located in the suction line at the exit of the evaporator
pod.
e. Compressor Suction Temperature Sensor (CST)
Provides micro with suction temperature information to
be displayed, recorded in the data recorder and used to
control the refrigeration system. It is located on the
suction line near the filter drier.
f. Ambient Air Temperature Sensor (AAT)
AAT is a temperature control probe which provides mi-
cro with ambient air temperature information to be dis-
played, recorded in the data recorder and used to con-
trol the refrigeration system. It is located behind the
condenser grille.
2.4 COMPARTMENT 1 EVAPORATOR SECTION
The main evaporator fits into a rectangular opening in
the upper portion of the trailer or rail car front wall. When
installed, the evaporator section is located inside this
refrigerated compartment, and the condensing section
is outside.
The main evaporator assembly consists of an
evaporator coil, evaporator fan motors, electronic
expansion valve, evaporator coil heaters, heat
exchanger, defrost termination sensor and supply and
return air sensors (See Figure 2-3) and high
temperature safeties.
Heating is accomplished by electric evaporator coil
heaters.
Automatic evaporator coil defrosting is initiated by either
sensing the air pressure drop across the coil with a
differential air switch or with the defrost timer in the
microprocessor.
2.4.1 Electronic Expansion Valve (EVXV)
The electronic expansion valve is an electronic device
which controls the flow of liquid to the evaporator ac-
cording to changes in superheat to the refrigerant leav-
ing the evaporator. The expansion valve maintains a
relatively constant degree of superheat in the gas leav-
ing the evaporator regardless of suction pressure. The
valve has a dual function -- automatic expansion control
and prevention of liquid return to the compressor.
2.4.2 Heat Exchanger
The heat exchanger is of the tube in tube type con-
nected in the main suction line and liquid line. Within the
heat exchanger, the cold suction gas is used to cool the
warm liquid refrigerant. This results in greater system
capacity and efficiency.
2.4.3 Evaporator Coil
The unit evaporator is a tube in fin type. The operation of
the compressor maintains a reduced pressure within
the coil. At this reduced pressure, the liquid refrigerant
evaporates at a temperature sufficiently low enough to
absorb heat from the air.
2.4.4 Transducers and Sensors
a. Evaporator Outlet Pressure Transducer (EVOP)
Provides micro with evaporator outlet suction pressure
information to be displayed, recorded in the data
recorder and used to control the refrigeration system. It
cannot be calibrated. It is located in the evaporator
section near the electronic expansion valve in the
suction line.
b. Evaporator High Temperature Switch (EVHTS)
EVHTS is a safety switch which turns off the electric
heaters if the temperature in the evaporator compart-
ment reaches 130
°
F (54.4
°
). It is located on the road-
side evaporator support bracket above the coil.
c. Evaporator Outlet Temperature Sensor (EVOT)
Provides micro with evaporator outlet suction
temperature information to be displayed, recorded in
the data recorder and used to control the refrigeration
system. It is located on the suction line near the
electronic expansion valve and is wrapped with
insulating tape.
d. Defrost Termination Temperature Sensor (1DTT)
1DTT is located on the center tube sheet of the evapora-
tor section. It senses the temperature of the evaporator
and allows defrost initiation once the temperature falls
below 40
°
F (4.4
°
C)
e. Return Air Temperature Sensor (1RAT)
1RAT is a temperature control probe which provides
micro with return air temperature information to be dis-
played, recorded in the data recorder and used to con-
trol the refrigeration system. It is located on roadside of
the return air grille.
Summary of Contents for VECTOR 1800 MT
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Page 2: ...OPERATION SERVICE MANUAL for VECTOR 1800 MT Trailer Multi Temp Refrigeration Units ...
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Page 20: ...1 6 62 11039 62 03958 00 Heat Warning 62 03957 01 High Voltage 62 60280 00 Standby Safety ...
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