Thermo King Precedent S-600, Operator'S Manual

Page: 29 / 221

Unit Description
26
SMART REEFER
TM
4 (SR-4)
Control System
The SR-4 is a microprocessor control system designed for
transport refrigeration. The SR-4 integrates the following
functions: changing setpoint and operating mode, viewing
gauge, sensor and hourmeter readings, initiating defrost cycles,
and viewing and clearing alarms.
The microprocessor components are located inside the control
box, which is located inside the lower roadside service door. It
is used to operate the unit. The control panel is mounted on the
face of the control box. It is clearly visible through an opening
in the lower roadside service door.
See “Operating Instructions” for more information about the
SR-4 Controller.
Depending on the air temperature in the trailer, as sensed by
the microprocessor Base Controller, the unit will typically
operate in one of the following modes:
Diesel Operation
In diesel operation the microprocessor will select the operating
mode from the following:
• High Speed Cool
• Low Speed Cool
• Low Speed Modulated Cool
• Null (CYCLE-SENTRY operation only)
• Low Speed Modulated Heat
• Low Speed Heat
• High Speed Heat
• Defrost
Electric Operation
In electric operation the microprocessor will select the
operating mode from the following:
• Cool
• Modulated Cool
• Null (CYCLE-SENTRY operation only)