Thermo King 002008, Manual

Page: 125 / 155

Remote Evaporator Unit Description
125
The Spectrum SB multi-temperature refrigeration
system provides heavy duty temperature control
for multiple compartment trailers. The system
provides direct expansion cooling in all trailer
compartments. Non-contaminating refrigerant
tap-ins in the host unit evaporator provide
convenient refrigerant piping connections for the
remote evaporator(s).
The host unit mounts on the front of the trailer
with the evaporator protruding into the trailer. The
remote evaporator(s) is a ceiling mounted
Spectrum unit.
Heat and defrost is provided in all compartments
by circulating hot refrigerant gas through the
evaporators.
Controls for the remote evaporator(s) are located
on the host unit (and in the optional remote
control box if so equipped).
Unit Operation
The remote evaporator cycles between cool, null
and heat to maintain the trailer’s compartment(s)
at the setpoint. The operating modes include Cool,
Null, Heat, and Defrost.
Power to run the direct current fan motors is
supplied by the alternator in the host unit.
When cooling is required, the Smart Reefer
Multi-Temp µP-IV microprocessor energizes the
remote liquid line solenoid valve. Refrigerant
flows through the evaporator coil to provide
cooling.
When the compartment temperature is near
setpoint, the Smart Reefer Multi-Temp µP-IV
microprocessor de-energizes the remote liquid
line solenoid valve and switches the remote
evaporator to null.
The Smart Reefer Multi-Temp µP-IV
microprocessor energizes the remote hot gas
solenoid when the 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 fan stops during defrost. The
Defrost mode will continue until the evaporator
coil temperature rises to 57 F (14 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
NOTE: The controller locks out heat at setpoints
below 15 F (-9.5 C).
Unit Features
• Direct Expansion Evaporator Coil
• Smart Reefer Multi-Temp µP-IV
Microprocessor
• 12 Vdc Fan Motor
• Aluminum Housing
• Liquid Line Solenoid
• Hot Gas Solenoid
• Suction Line Solenoid
• Liquid Return Check Valve