Additional Compressor Alarms; Refrigerant Low Pressure Alarm; Economizer; Economizer Components - Bard MEGA-TEC W120AP Service Instructions Manual

These delays can be changed 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 Adv System
Config; press ENTER key.
4. Press UP or DOWN keys to scroll to Comp. Safety
B2; press ENTER key.
5. Press ENTER key to scroll to Min On Time or Min
Off Time (see Figure 31).
6. Press UP or DOWN keys to change the value.
7. Press ENTER key to save value and move the
cursor to next parameter or top of screen.
8. Press ESCAPE key several times to return to Main
Menu screen.
The address-based delay only applies to the wall-mount
unit when in orphan mode. The controller will delay the
unit compressor based on the value entered on screen
B2 multiplied by the unit address. This is intended to
keep multiple units from starting their compressors
at the same time when there is a quick change in the
load. When connected to the LC, this is taken care of
by LC logic.
FIGURE 31
Adjusting Compressor Delays

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.
Manual 2100-671
Page 24 of 44

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 three dampers powered by three 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 exhaust damper (damper 2) is
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 Damper
System 1/5.
5. To override the current position, press ENTER key
to scroll to System OV Pos (see Figure 32).
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 Enable Sys. OV.
8. Press UP or DOWN keys to change the value from
No to Yes.
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 Sys. OV is changed back to No.
FIGURE 32
Damper Override