Manual 2100-670I
Page
23 of 47
8. Once adjusted, the ESCAPE key several times to
return to Main Menu screen.
Discharge/Liquid Pressure Transducer Alarm
When the discharge pressure transducer value is out
of range (0-650 PSIG), the controller will generate a
sensor failure alarm to indicate the transducer is not
working properly.
This alarm is fixed and cannot be adjusted.
Liquid Temperature Sensor
The unit is equipped with a liquid line temperature
sensor to monitor the temperature of the liquid
refrigerant leaving the condenser and entering the EEV.
The temperature is measured with a 10k ohm NTC
thermistor.
The liquid temperature 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
Liquid Temp
Sensor (C3)
; press ENTER key.
5. Reference the
Value
to verify the temperature (see
Figure 38).
6. If an offset needs to be applied, press ENTER key
to scroll to
Offset
.
7. Press UP or DOWN keys to change the offset to
desired value.
8. Press ENTER key to save.
9. Press ESCAPE key several times to return to Main
Menu screen.
FIGURE 37
Voltage to Pressure:
Discharge/Liquid Pressure Transducer
Troubleshooting the Discharge/Liquid Pressure
Transducer
0-650 psig
0-5vdc
4v/650 psig = .00615 volts per 1 psig
Example:
325 psig x .00615 + .5 v = 2.5 volts
Formula for Tech:
Measured Pressure x .00615 + Sensor Offset =
Expected Transducer Signal Voltage (see Figure 37).
FIGURE 36
Adjusting Discharge/Liquid Transducer
Pressure Values
FIGURE 38
Adjusting Discharge/Liquid Temperature Input
Condenser Fan Operation
Condenser Fan Speed Control
Mechanical Cooling Only
The condenser fan motor speed is selected based on
outdoor air temperature. Above 80°F, the fan speed
will be set to a nominal output speed. Below 80°F, the
condenser fan speed will operate at reduced speeds
based on outdoor air temperatures until the slowest fan
speed is reached. This operation allows for more stable
head pressures at lower ambient conditions, which also
allows for increased unit efficiency. See Figure 39 on
page 24 for more detail.
NOTE:
If the outdoor temperature sensor fails, the
condenser fan speed will be set to the nominal
operating speed.
Optimized Cooling (Concurrent Economizer and
Mechanical Cooling)
During optimized cooling mode, the condenser fan
motor speed will be set to the normal operating speed
and will not change based on outdoor air conditions. If
