Liquid Pressure Sensor; Troubleshooting The Discharge/Liquid Pressure Transducer; Figure 28 Enabling Fan Override; Figure 29 Adjusting Discharge/Liquid Transducer Pressure Values - Bard MEGA-TEC W090A Service Instructions Manual

4. Press UP or DOWN keys to scroll to Fans / Blowers;
press ENTER key.
5. Press UP or DOWN keys to scroll to Condenser Fan
1 (see Figure 28).
6. Press ENTER key to scroll to the Fan Overrides?
7. Press UP or DOWN keys to change the value from
No to Go. The override will begin and the screen
will change to the override screen (see Figure 28).
The override will last for 5 minutes or until the Fan
Overrides parameter is set to No again.
FIGURE 28
Enabling Fan Override

Liquid Pressure Sensor

The unit has a pressure transducer installed on the liquid
line between the condenser and electronic expansion
valve (EEV). The transducer is used for condenser fan
speed control and for monitoring of system operation.
The liquid line transducer is also referred to as the
discharge or liquid pressure sensor.
The discharge/liquid pressure sensor input 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 Analog Inputs;
press ENTER key.
5. Press UP or DOWN keys to scroll to Analog Ins 7/19
(for circuit 1) or Analog Ins 9/19 (for circuit 2).
Manual 2100-671C
Page 22 of 59
6. Verify the measurement displayed on screen is
accurate (see Figure 29).
7. If the measurement needs to be adjusted, apply an
offset value by pressing the ENTER key to scroll to
Offset.
8. Press UP or DOWN keys to adjust the offset. The
update will not take effect until the cursor is
moved out of the offset parameter.
9. Once adjusted, the ESCAPE key several times to
return to Main Menu screen.
FIGURE 29
Adjusting Discharge/Liquid Transducer
Pressure Values
Troubleshooting the Discharge/Liquid Pressure
Transducer
0-650 psig
.5 to 4.5v
4.5-.5 + 4 volt range/650 psig = .00615 volts per 1 psig
Example: 325 psig x .00615 + .5 v = 2.5 volts
Formula for Tech:
Measured Pressure x .00615 + Voltage Offset =
Expected Transducer Signal Voltage (see Figure 30).
FIGURE 30
Voltage to Pressure:
Discharge/Liquid Pressure Transducer
Voltage Offset