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The ESC3 features a number of options to customize
operation and termination of a defrost cycle. A defrost
cycle can be terminated based on time or temperature.
When termination by temperature is used, a minimum
and maximum defrost time can be specified.
You may also program the ESC3 to begin a defrost cycle
after power-up (after a user-defined delay time) and initi-
ate a defrost manually (see the description for “Defrost
Key” on this page).
Alarm Control
The ESC3 has several alarm functions. In addition to
alarms based on high and low air temperatures, it will
alarm if a probe failure is detected. If you are using
defrost, the ESC3 will also generate an alarm when the
defrost cycle did not terminate as expected (such as
when the ESC3 is programmed to terminate at a temper-
ature set point and the set point was never reached).
Interface
The ESC3 features a 3 digit LED display that shows the
case temperature. Alternately, the display can be config-
ured to display the product temperature if a product tem-
perature probe is connected. The temperature can be
displayed in either °C or °F.
Three keys on the front panel provide an indication of
operating status as well as allowing setpoints to be
changed.
Alarm Key
The Alarm key illuminates when the controller has detect-
ed an alarm condition. This key is also used to reset an
alarm condition and to enter the setup mode (allowing
setpoints to be changed).
Compressor Key
The Compressor key illuminates when the compressor
output is on. When the ESC3 is in setup mode, this key is
used to select a setpoint to be modified and to change the
value of the setpoint.
Defrost Key
The Defrost key illuminates when the ESC3 is in defrost
mode. Press the defrost key for 5 seconds to go into man-
ual defrost mode. The key is also used in setup mode to
select a setpoint to be modified and to change the value
of the setpoint.
CONTROL SETTINGS
Operation
Temperature Control
Temperature control in the ESC3 is accomplished by com-
paring the temperature reading of the case temperature
probe against the temperature setpoint. The compressor out-
put is used to control the temperature. If the temperature is
above the temperature setpoint (L1) + the hysteresis setpoint
(rd), the compressor output is turned on (subject to the con-
ditions described in the compressor operation sec-tion). If
the temperature is below the temperature setpoint – the hys-
teresis set-point, the compressor output is turned off. Note
that the compressor output can also be used to control a
refrigeration solenoid to regulate the temperature in a case.
Compressor Control
Several setpoints are available that allow the operation of the
compressor output to be tailored to match individual needs.
Min On/Off Times and Minimum Cycle Time
Minimum ON/OFF compressor times can be specified, as
well as a minimum time delay between compressor cycles.
These parameters help prevent short-cycling.
Compressor Power ON Delay
The compressor power on delay set-point (c0) allows the
user to specify a delay after the power up of the controller.
The compressor output will not come on regardless of the
temperature reading, until this amount of time has expired.
Compressor Safety Cycle
If the temp sensor fails, the ESC3 can be programmed to
cycle the compressor ON for a fixed amount of time, followed
by a 15-minute OFF time, until the probe failure is fixed. You
may also specify the compressor be fully ON or OFF during
probe failure.
Fan Control
The fan output is controlled by the ESC3 based on the cur-
rent operating mode (defrost, cooling, etc.) and the setpoints
which affect fan operation. It may be set to run only when
required based on case temperature, or it may be set to be
always ON regardless of temperature. In addition to these
two basic modes, you may also turn the fans OFF during
defrost, specify the fan will be ON only when the compressor
is running, and delay fan activation after defrost drip time.
Defrost Control
The ESC3 can control the defrost function of a case. The
ESC3 executes defrost cycles at a user-defined time interval.
Electric, Off Cycle and Hot Gas defrost types are supported.
ESC3 Controls