Truck/Trailer Refrigeration Unit - Sunbelt Transport Refrigeration

More documents

Recommendations

Info

c. To Remove a Pre-set Setpoint1. Start unit and press system on/off button to ONposition (see Figure 2-1).2. Switch OFF each compartment, unit will stop.3. Press manual defrost button for 10 seconds. P1will be displayed in all compartments.4. Set temperature to lowest possible and OF willbe displayed .5. Switch system on/off switch on the unit to OFF.This erases the pre-set setpoints in memory.2.5 CONTROL CIRCUIT OPERATION --ENGINE DRIVE2.5.1 IntroductionNOTETo make it easier to locate the schematiccomponents referred to in the written text, theschematic in this manual has map coordinatesadded to the margins. These locations have alsobeen added to the legend.The controller boards shown on the electricalschematic (Figure 5-1) that interface with unitcomponents are: analog interface or processor board onthe left and the relay module on the right.Connections to these boards are made through threemultiple-pin plug connectors HC, HC2, & MP. Theaddress system (i.e. HCD2-MPW2) indicates a wirebetween plug HC, pin D2 and microprocessor MP & pinW2.The processor board connections are mainly inputsand outputs for control switches, temperature sensors,safety, and auto start functions that control the operationof the unit. The processor board also controls theoperation of the relay board through plug connections.The relay module, which contains plug-ininterchangeable relays, provides the microprocessor witha means for switching the unit components to achieve adesired operating mode.2.5.2 CoolingThere are two control ranges, Frozen and Perishable.The Frozen range is active with set points at or below--- 12_C(+10_F) and the Perishable range is active at setpoints above --- 12_C (+10_F).The controller automatically selects the modenecessary to maintain box temperature at set point (seeFigure 2-2 or Figure 2-4).If the unit is in high speed cool, the microprocessorwill pull terminal N3 low to energize the speed relay. A setof normally open contacts (SR) close to energize thespeed control solenoid (SCS). The engine will be in highspeed.For truck units, as the box temperature falls towardset point, the microprocessor will place the unit in lowspeed cool. The speed relay (SR) de-energizes to openthe circuit to the speed control solenoid (SCS). Enginespeed decreases from high speed to low speed.With decreasing temperature, the unit will shift toNull and then to low speed heat.The unit will remain in various stages of heating untilthe box temperature increases enough to place the unit inthe null mode. As the box temperature increases, the unitwill shift to cool mode.2.5.3 HeatingRefer to Section 1.15 for a description of the heatingcycle.The controller automatically selects the modenecessary to maintain box temperature at set point. Theheating modes are as follows with descendingtemperatures:(a) Low Speed Heating(b) High Speed HeatingThe controller will shift the unit into low speedunloaded heat when the box temperature falls below setpoint. The microprocessor pulls terminal X1 low tocomplete the ground paths for the heat relay (HR1).If more heatingcapacity is required, the unit willshiftto high speed heating. The microprocessor energizesHR1 and speed relay (SR) coils. Terminals X1 and N3 willbe pulled low. SR contacts close to energize the speedcontrol solenoid (SCS). The engine will be in high speed.2.5.4 DefrostRefer to Sections 1.15 and 2.8for the heat and defrostcycle.NOTEThe unit will be in high speed in the defrostmode.The defrost mode may be initiated two differentmethods if the evaporator coil is below 1.7_C (35_F).(Refer to Section 1.5)Method one, to initiate defrost press the ManualDefrost Key.Method two is that defrost may be initiatedautomatically at preset intervals by the defrost timer inthe microprocessor. (Refer to Section 1.8.4). The manualdefrost key and defrost timer are part of themicroprocessor and are not shown on the schematic.In defrost, the microprocessor pulls terminals X1and N3 low to shift the unit into high speed heat. Theprocessor also pulls terminal W2 low to energize thedefrost relay coil. The defrost and heat display will also beilluminated.Normally closed defrost relay contacts open to tostop the evaporator fans.2-3 62-02884
2.6 CONTROL CIRCUIT OPERATION --STANDBY MOTOR DRIVENOTETo make it easier to locate the schematiccomponents referred to in the written text, theschematic in this manual has map coordinatesadded to the margins. These locations have alsobeen added to the legend.The relay module, which contains plug-ininterchangeable relays, provides the controller with ameans for switching the unit components to achieve adesired operating mode.2.6.1 Electric Standby Features1. Two Operating Modes2. Minimum “ON” Time (5 Minutes)3. Minimum “OFF” Time (5 Minutes)4. Low Battery Protection1. Two operating modes are available: ElectricStandby can operate in the Start/Stop mode or theContinuous Run mode.In the Start/Stop mode, when the box temperaturegets close to setpoint, the controller will cycle the StandbyMotor(SBM) OFF to conserve energy.2. Minimum “ON” time (five minutes): The unitmust run for the minimum run-time before it can considershutting off. This minimum run time is to prevent shortcycling and ensure adequate air flow through the load toallow the controller to accurately sense load temperatureand bring the battery up to minimum voltage level. It alsoprevents “hot spots” in a properly loaded box.After the minimum run time is complete, themicroprocessor will look at the remaining conditions thatmust be satisfied to allow a shutdown. These are:A) Battery condition --- Battery voltage must beabove 13.4 volts (measured at Y1).B) The box temperature (active probe) must besatisfied:Perishable Range Setpoints +/ --- 0.5_CFrozen Range Setpoints + 0.5_CIf ALL of these conditions are not satisfied, themotor will continue to run until they are. This preventsrapid cycling of the electric drive motor.3) Minimum “OFF” time (5 minutes): Once themotor has cycled off, it will remain off for the minimum“off time”. This prevents the motor from rapid cyclingdue to changes in air temperature. Air temperature in thebox can change rapidly, but it takes time for the producttemperature to change.4) Low battery voltage protection: Themicroprocessor will restart the unit, if the battery voltagedrops below 11.0 volts, to recharge the battery after theminimum off-time delay.NOTEWhen in Continuous Run, Perishable range, theunit will cycle between Cool and Heat tomaintain box temperature at setpoint. In Frozenrange the unit will run in Cool only. ContinuousRun is normally used for perishable productsthat require constant air flow.2.6.2 Standby CoolWhen in standby cool, Start/Stop, themicroprocessor will energize the following circuits:After a five second delay the Diesel Electric Relay(DER) will be energized, this will open the N.C. (DER)contacts to prevent the Fuel Heater Relay (FHR), FuelPump (FP) and the Fuel Solenoid (FS) from beingenergized during standby operation. At the same timethe N.O. (DER) contacts will close. This will energize theMotor Contactor (MC). With the motor contactorenergized, the N.O. (MC) contacts will close, supplyingvoltagetoenergizethestandbymotor.At the same time, (RR) will be energized, closing theN.O. (RR) contacts supplying voltage to the refrigerationcontrol circuitry.2.6.3 Standby OFFIn the start/stop mode, after the standby motor hasrun at least five minutes and the controller is ready toswitch from cool to heat (box temperature near setpoint),the microprocessor will de-energize the (RR) causing thestandby motor to cycle off.The unit will remain off for at least five minutesbefore restarting. If after five minutes, the batteryvoltage drops below 11.0 volts or the box temperaturedrifts out-of-range, +/--- 2.0_C (3.6_F) from setpoint forperishable range and +2.0_C (3.6_F) above setpoint forfrozen range, the standby motor will restart.2.6.4 Standby DefrostStandby defrost operates the same as engine drivedefrost. Refer to Section 2.5.4.62-028842-4
Page 5 and 6: TABLE OF CONTENTS (CONT’D)Section
Page 7 and 8: LIST OF ILLUSTRATIONSFigurePage4-18
Page 9 and 10: 61 2 3 4 57 811 1091. Muffler2. Eng
Page 11 and 12: 213 4 58 106793 41. Run-Stop Switch
Page 13 and 14: 113214345678910151617111812191. Mai
Page 15 and 16: 1231. Fault Light2. Standby Power L
Page 17 and 18: e. EvaporatorsThe compartments of t
Page 19 and 20: 1.2 ENGINE DATAEngine Model CT4-134
Page 21 and 22: 1.7 SAFETY DEVICESSystem components
Page 23 and 24: 2 3 4 5 6 7 8 9 101FUNCTIONO ISETPO
Page 25 and 26: 1.8.6 FUNCTIONAL PARAMETERSThe func
Page 27 and 28: Engine HoursThe number of diesel en
Page 29 and 30: Coolant Temperature Sensor AlarmThe
Page 31 and 32: g. Minimum On-TimeThe engine is all
Page 33 and 34: 1.12.3 Hot Gas Bypass Unloadera. Ma
Page 35 and 36: 1.14 REFRIGERANT CIRCUIT DURINGCOOL
Page 37 and 38: 1614513LSV31715HGV31614513LSV21715H
Page 39 and 40: 1614513LSV3 (NC)1715HGV3 (NC)161451
Page 41: 2.2.2 MANUAL STARTINGa. Starting In
Page 45 and 46: FALLING TEMPERATURERISING TEMPERATU
Page 47 and 48: 62-028842-8Table 2-3. 3 Compartment
Page 49 and 50: INDICATION/TROUBLEPOSSIBLE CAUSESRE
Page 55 and 56: 4.2 MAINTENANCE SCHEDULE (TRAILER)U
Page 57 and 58: 1105432shaft). Energize solenoid fo
Page 59 and 60: . Electrical Pump (See Figure 4-4)T
Page 61 and 62: a. Alternator V-Belts (Trailer Unit
Page 63 and 64: 4.7 PUMPING THE UNIT DOWN ORREMOVIN
Page 65 and 66: 1. Suction Line2. Equalizer Line3.
Page 67 and 68: k. Slide compressor enough to clear
Page 69 and 70: . Solenoid Coil ReplacementNOTEThe
Page 71 and 72: 4.18.2 Solenoid Valve -- Sporlana.
Page 73 and 74: 4.22 CONFIGURATION OF MICROPROCESSO
Page 75 and 76: 4.25 5KW GENERATOR -- TRAILERThe 5K
Page 77 and 78: 4.27 SERVICING PHASE SEQUENCEWARNIN
Page 79 and 80: 4.30 THERMOSTATIC EXPANSION VALVETh
Page 81 and 82: Table 4-7. R-404A Pressure -- Tempe
Page 83 and 84: 62-028845-2Figure 5-1. Truck Units
Page 85 and 86: 5-4Figure 5-2. Truck Units --- Elec

Truck/Trailer Refrigeration Unit - Sunbelt Transport Refrigeration

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?