Additional Compressor Alarms; Refrigerant Low Pressure Alarm; Economizer; Economizer Components - Bard MEGA-TEC W180B Service Instructions Manual

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 Digital
Outputs; press ENTER key.
5. Press UP or DOWN keys to scroll to Digital Outputs
C2-3.
6. Press ENTER key to scroll to Enable Override (see
Figure 42).
7. Press UP or DOWN key to change value to Yes.
8. Press ENTER key to scroll to selected compressor
output.
9. Press UP or DOWN key to change value to On or
Off.
FIGURE 42
Overriding Compressor Outputs

Additional Compressor Alarms

Refrigerant Low Pressure Alarm

When the suction pressure transducer indicates
a pressure value less than the low pressure alarm
setpoint of 40 PSIG and there is an active call for
cooling, the controller will disable the compressor (after
a 120-second delay). NOTE: The second call will be
delayed based on the delay off value mentioned in the
compressor section. The controller will try to run the
refrigeration system two (2) times within 900 seconds
before the alarm will lock the compressor out. This
alarm needs to be manually cleared before compressor
operation will resume.

Economizer

Economizer Components

Actuator

The actuator rotates up to 90° based on a 2-10V
signal sent to it by the controller. This component is
what opens and closes the damper blade. The unit is
equipped with four dampers powered by four separate
actuators. The left intake damper (damper 1) and the
right intake damper (damper 3) are each powered by a
44 in-lb actuator. The left exhaust damper (damper 2)
and right exhaust damper (damper 4) are powered by a
90 in-lb actuator. All dampers are spring return and will
close the damper if power is lost.
To verify the output from the controller to the actuator:
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 Analog
Outputs; press ENTER key.
4. Press UP or DOWN keys to scroll to Analog Outputs
C4-5.
5. To override the current position, press ENTER key
to scroll to Enable Override (see Figure 43).
6. Press UP or DOWN keys to change the value to the
desired output.
7. Press ENTER key to save the value and move
cursor to Damper 1 Pos, Damper 2 Pos, Damper 3
Pos. or Damper 4 Pos.
8. Press UP or DOWN keys to change the value to the
desired position.
9. The damper position will update with the new
override value and the damper will travel to that
position.
NOTE: This override will last for 5 minutes or until the
Enable Override is changed back to No.
FIGURE 43
Damper Override

Dust Sensor

The unit has a dust sensor installed near the outdoor air
inlet. The dust sensor checks for excessive particulates
in the outdoor air, and will close the economizer if
the dust is excessive. The sensor uses a PWM signal
converted to 0-5V output to the controller.
To ensure proper performance, cleaning may be
required. Vacuuming or blowing the dust off the sensor
with forced air is recommended. Avoid inserting any
objects into the sensor.
Manual 2100-749
Page 29 of 68