Unit Description
24
valve may open. When the return air temperature
begins to move away from the setpoint, the ETV
begins to open and the hot gas bypass valve closes
(if it was open). This provides very smooth and
steady temperature control and the temperature
does not oscillate above and below setpoint as
much as it does in a unit that does not have
modulation control.
SMART REEFER 4 (SR-4) Control
System
The SR-4 is a microprocessor control system
designed for a transport refrigeration system. The
SR-4 integrates the following functions:
•
Changing setpoint and operating mode
•
Viewing gauge, sensor and hourmeter
readings
•
Initiating Defrost cycles
•
Viewing and clearing alarms.
The microprocessor components are located
inside the control box, which is located inside the
lower roadside service door. The microprocessor
is connected to an HMI (Human Machine
Interface) Control Panel. It is used to operate the
unit. The HMI 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 the Operating Instructions Chapter for more
information about the SR-4 controller.
CYCLE-SENTRY™ Start-Stop
Controls
The CYCLE-SENTRY Start-Stop fuel saving
system provides optimum operating economy.
When CYCLE-SENTRY Mode is selected the
unit will start and stop automatically to maintain
setpoint, keep the engine warm and the battery
charged. When Continuous Mode is selected, the
unit starts automatically and runs continuously to
maintain setpoint and provide constant airflow.
NOTE: The SR-4 controller provides a wide
range of control and programming flexibility.
However, pre-programming of the unit
controller may prohibit operation in certain
temperature ranges within some modes and may
also prohibit certain modes of operation. Refer
to TK 55533 the SR-4 Microprocessor Control
System Diagnostic Manual for information
about controller programming.
In CYCLE-SENTRY if the block temperature
falls below 30 F (-1 C), the engine will start and
run until the block temperature is above 90 F (32
C). If the battery voltage falls to the programmed
limit selected by CYCLE-SENTRY Battery
Voltage (typically 12.2 volts) and Diesel
CYCLE-SENTRY mode is selected, the engine
will start and run until the charge rate falls below
that programmed by CYCLE-SENTRY Amps
(typically 5 amperes).
Features of the CYCLE-SENTRY system are:
•
Offers either CYCLE-SENTRY or
Continuous Run operation.
•
Controller regulated all season temperature
control.
•
Maintains minimum engine temperature in
low ambient conditions.
•
Battery Sentry keeps batteries fully charged
during unit operation.
•
Variable preheat time.
•
Preheat indicator buzzer.
Data Logging
There are two separate data loggers. The data is
downloaded through the Flash Drive Only USB
port on the front of the control box using a flash
drive and ThermoServ™ software.
WARNING: Do not operate the unit until
you are completely familiar with the
location and function of each control.
WARNING: The unit can start at any time
without warning. Press the
O
FF
key on the
HMI control panel and place the
microprocessor On/Off switch in the Off
position before inspecting or servicing any
part of the unit.
