Unit Description
26
about installing the CargoLink system and
sensors, and troubleshooting problems with the
system.
OptiSet Plus™
OptiSet Plus is a group of programmable
functions that control how the unit will operate
with specific setpoints or named products. This
assures that when a particular setpoint named
product is selected, the unit will always operate
the same way. This allows an entire fleet to be
configured to match customers’ needs. Refer to
TK 55533 the SR-4 Microprocessor Control
System Diagnostic Manual and ThermoServ Help
for configuration instructions.
FreshSet™
FreshSet is included in OptiSet Plus. FreshSet is a
demand base temperature control for fresh
products. FreshSet modifies and adjusts unit
airflow operation to control temperature and to
maximize protection of cargo, while keeping
operating costs to a minimum. Refer to TK 55533
the SR-4 Microprocessor Control System
Diagnostic Manual for configuration instructions.
Sequence of Operation
When the Microprocessor On/Off switch is turned
on and Controller
O
N
key is pressed, the LCD
display is illuminated and shows the setpoint and
the return air temperature. If the
CYCLE-SENTRY mode has been selected, the
unit will start and stop automatically. If the
Continuous mode has been selected, the unit will
start and run automatically.
Operating Modes
The microprocessor uses a complex program to
determine which operating mode the unit should
be in. Therefore, it is difficult to predict which
operating mode the unit should be in by
comparing the setpoint to the box temperature.
In diesel operation the diesel engine operates at
either low speed or high speed as determined by
the microprocessor. The unit will Cool or Heat in
either high or low speed. The unit will Defrost in
low speed only. Heat and Defrost consists of hot
gas delivered to the evaporator coil distributor.
In electric operation (SmartPower units only) the
drive motor operates at a single speed. It does not
run in Null. Electric evaporator heaters are also
used to increase the Heat and Defrost capacities
during electric operation.
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)
•
Modulated Heat (Hot Gas only)
•
Hot Gas Heat
•
Full Heat (Hot Gas and Electric Heat)
•
Defrost (Hot Gas and Electric Heat)
Defrost
Frost gradually builds-up on evaporator coils as a
result of normal operation. The unit uses hot
refrigerant to defrost the evaporator coils. Hot
refrigerant gas passes through the evaporator coil
and melts the frost. The water flows through
collection drain tubes onto the ground. The
methods of Defrost initiation are Automatic, and
Manual.
Automatic Defrost:
The controller is programmed
to automatically initiate timed or demand defrost
cycles. The SR-4 microprocessor can be
programmed to initiate timed defrost cycles at
