Thermo King T-1000R, Maintenance Manual

Page: 274 / 282

Remote Evaporators 16-2
UNIT DESCRIPTION
The SPECTRUM SR-2/3 multi-temperature refrigeration system provides heavy duty temperature control for multiple
compartment trucks. The system provides direct expansion cooling in all cargo compartments.
Heat and defrost is provided in all compartments by circulating hot refrigerant gas through the remote evaporators.
The remote evaporators are controlled by the SR-2/3 Multi-Temp Control System directly and through the expansion module.
The SR-2/3 Multi-Temp Control System is located in the condenser section of the unit. Wire harnesses connect the remote
evaporators to the interface board and expansion module. The expansion module is connected to the base controller/interface
board assembly through the CAN bus. Refer to the Truck SR-2/3 Multi-Temp Diagnostic Manual TK 54293 for more information
about the SR-2/3 Multi-Temp Control System.
Unit Operation
The remote evaporators cycle between cool, null and heat to maintain the truck’s compartments at the setpoints. The operating
modes include Cool, Null, Heat, and Defrost.
Power to run the direct current fan motors is supplied by the alternator in the condenser section.
When cooling is required, the SR-2/3 Multi-Temp Control System energizes a remote liquid line solenoid valve. Refrigerant
flows through that evaporator coil to provide cooling.
When the compartment temperature is near setpoint, the SR-2/3 Multi-Temp Control System de-energizes the remote liquid line
solenoid valve and switches that remote evaporator to null.
The SR-2/3 Multi-Temp Control System energizes a remote hot gas solenoid when a remote compartment requires heat or
defrost.
Defrost
The Defrost mode can be initiated any time the evaporator coil temperature is below 45 F (7 C). Defrost is initiated automatically
by the controller or manually by selecting defrost from the Defrost Prompt Screen for the desired zone.
The evaporator fans stop during defrost. The Defrost mode will continue until the evaporator coil temperature rises to 58 F (14.5
C), causing the controller to terminate defrost. After Defrost, the evaporator may shift back to Cool, Null or Heat.
Operating Modes
Remote evaporator operating modes are:
• Cool
• Null
• Heat
• Defrost
The controller locks out heat at setpoints below 15 F (-9.5 C).
Unit Features
• Direct Expansion Evaporator Coil
• SR-2/3 Multi-Temp Control System with Expansion Module
• 12 Vdc Fan Motor
• Aluminum Housing
• Liquid Line Solenoid
• Hot Gas Solenoid
• Suction Line Solenoid
• Liquid Return Check Valve
Unit Protection Devices
• Smart FETs in the expansion module.