Manual 2100-670
Page
12 of 32
Dehumidification
The unit uses a dehumidification sequence that does
not require the electric heat to run at the same time
as the compressor. Instead, the unit will turn on the
compressor to cool down to the heating setpoint.
Once the lower setpoint has been reached, the unit
will heat the space back up to the upper setpoint.
This cycle continues until the humidity level in the
shelter reaches an acceptable level. At this point,
the unit will revert back to normal operation. The
economizer will also be disabled while the unit is in
the dehumidification mode.
NOTE:
This feature is dependent upon the LV1000
indoor humidity sensors and a command from
the LV to enter dehumidification mode. See
LV1000 Service Instructions 2100-673 for
adjustment of the dehumidification setpoint
and differentials.
Electronic Expansion Valve (EEV)
EEV Components
Electronic Expansion Valve
The electronic expansion valve is a stepper motor that
is controlled with a step output from the controller. The
valve is capable of 480 steps represented by a 0-100%
signal on the controller. The motor drives a needle valve
that regulates the flow of refrigerant.
Low Pressure Transducer
The unit has a low side pressure transducer installed
on the suction line between the evaporator coil
and compressor. The transducer is used for system
monitoring of low side system pressures. The sensor
is used with the suction temperature sensor to provide
a real time superheat calculation that determines the
EEV position.
This sensor can be verified and adjusted by:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
TECHNICIAN password 1313.
3. Press UP or DOWN keys to scroll to
I/O Config
;
press ENTER key.
4. Press UP or DOWN keys to scroll to
Suction Pr
Sensor (C11)
; press ENTER key.
5. Verify the measurement displayed on screen is
accurate (see Figure 11).
6. If the measurement needs to be adjusted, apply an
offset value by pressing ENTER to scroll to
Offset
.
7. Press UP or DOWN keys to adjust the offset.
8. The update will not take effect until the cursor is
moved out of the
Offset
parameter.
9. Once adjusted, press the ESCAPE key several
times to return to Main Menu screen.
Suction Pressure Alarm
When the suction temperature sensor value is out
of range (0-250 PSIG), the controller will generate
a sensor failure alarm to indicate the sensor is not
working properly.
This alarm cannot be adjusted.
Suction Temperature Sensor
The suction temperature sensor is used to calculate
superheat. The EEV uses this value to control the EEV.
The temperature is measured with a 10k ohm NTC
thermistor.
The suction temperature sensor measurement can be
verified and adjusted by:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
TECHNICIAN password 1313.
3. Press UP or DOWN keys to scroll to
I/O Config
;
press ENTER key.
4. Press UP or DOWN keys to scroll to
Suct Temp
Sensor (C9)
; press ENTER key.
5. Verify the measurement displayed on screen is
accurate (see Figure 12 ).
6. If the measurement needs to be adjusted, apply an
offset value by pressing ENTER to scroll to
Offset
.
7. Press UP or DOWN keys to adjust the offset.
8. The update will not take effect until the cursor is
moved out of the
Offset
parameter.
9. Once adjusted, press the ESCAPE key several
times to return to Main Menu screen.
Suction Temperature Alarm
When the suction temperature sensor value is out of
range (-41.0 to 303.0°F), the controller will generate
a sensor failure alarm to indicate the sensor is not
working properly.
This alarm cannot be adjusted.
FIGURE 11
Adjusting Low Pressure Sensor Values
