vector 1800 mt - Sunbelt Transport Refrigeration

2.3.6 Transducers and Sensorsa. Compressor Suction Pressure Transducer(CSP)Provides micro with suction pressure information to bedisplayed, recorded in the data recorder and used tocontrol 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 tobe displayed, recorded in the data recorder and used tocontrol the refrigeration system. It can be calibrated. It islocated on the center cylinder head of the compressor.c. Compressor Discharge Temperature SensorTransducer (CDT)Provides micro with discharge temperature informationto be displayed, recorded in the data recorder and usedto control the refrigeration system. It is located on thecenter cylinder head of the compressor.d. Compressor Suction Modulation Valve (CSMV)The CSMV opens and closes as required for capacitycontrol of the refrigeration system cooling cycle. It islocated in the suction line at the exit of the evaporatorpod.e. Compressor Suction Temperature Sensor (CST)Provides micro with suction temperature information tobe displayed, recorded in the data recorder and used tocontrol the refrigeration system. It is located on thesuction line near the filter drier.f. Ambient Air Temperature Sensor (AAT)AAT is a temperature control probe which provides microwith ambient air temperature information to be displayed,recorded in the data recorder and used to controlthe refrigeration system. It is located behind thecondenser grille.2.4 COMPARTMENT 1 EVAPORATOR SECTIONThe main evaporator fits into a rectangular opening inthe upper portion of the trailer or rail car front wall. Wheninstalled, the evaporator section is located inside thisrefrigerated compartment, and the condensing sectionis outside.The main evaporator assembly consists of anevaporator coil, evaporator fan motors, electronicexpansion valve, evaporator coil heaters, heatexchanger, defrost termination sensor and supply andreturn air sensors (See Figure 2-3) and hightemperature safeties.Heating is accomplished by electric evaporator coilheaters.Automatic evaporator coil defrosting is initiated by eithersensing the air pressure drop across the coil with adifferential air switch or with the defrost timer in themicroprocessor.2.4.1 Electronic Expansion Valve (EVXV)The electronic expansion valve is an electronic devicewhich controls the flow of liquid to the evaporator accordingto changes in superheat to the refrigerant leavingthe evaporator. The expansion valve maintains arelatively constant degree of superheat in the gas leavingthe evaporator regardless of suction pressure. Thevalve has a dual function -- automatic expansion controland prevention of liquid return to the compressor.2.4.2 Heat ExchangerThe heat exchanger is of the tube in tube type connectedin the main suction line and liquid line. Within theheat exchanger, the cold suction gas is used to cool thewarm liquid refrigerant. This results in greater systemcapacity and efficiency.2.4.3 Evaporator CoilThe unit evaporator is a tube in fin type. The operation ofthe compressor maintains a reduced pressure withinthe coil. At this reduced pressure, the liquid refrigerantevaporates at a temperature sufficiently low enough toabsorb heat from the air.2.4.4 Transducers and Sensorsa. Evaporator Outlet Pressure Transducer (EVOP)Provides micro with evaporator outlet suction pressureinformation to be displayed, recorded in the datarecorder and used to control the refrigeration system. Itcannot be calibrated. It is located in the evaporatorsection near the electronic expansion valve in thesuction line.b. Evaporator High Temperature Switch (EVHTS)EVHTS is a safety switch which turns off the electricheaters if the temperature in the evaporator compartmentreaches 130°F (54.4°). It is located on the roadsideevaporator support bracket above the coil.c. Evaporator Outlet Temperature Sensor (EVOT)Provides micro with evaporator outlet suctiontemperature information to be displayed, recorded inthe data recorder and used to control the refrigerationsystem. It is located on the suction line near theelectronic expansion valve and is wrapped withinsulating tape.d. Defrost Termination Temperature Sensor (1DTT)1DTT is located on the center tube sheet of the evaporatorsection. It senses the temperature of the evaporatorand allows defrost initiation once the temperature fallsbelow 40°F (4.4°C)e. Return Air Temperature Sensor (1RAT)1RAT is a temperature control probe which providesmicro with return air temperature information to be displayed,recorded in the data recorder and used to controlthe refrigeration system. It is located on roadside ofthe return air grille.62-110392--10