McQuay WSC Operating Manual page 78

Table 34, During starting, motor rotates but does not reach full speed
Fault Displayed.
Display shows Accel or
Run.
Motor Hums before turning
Table 35, Motor stops unexpectedly while running
Fault Displayed.
Display Blank, Heartbeat
LED on D3 board not
blinking.
Table 36, Metering incorrect
Motor Current or Voltage
meters fluctuating with
steady load.
Table 37, Other Situations
Motor Rotates in Wrong
Direction
Erratic Operation
Motor Overheats
Continued on the next page.
78
Condition
Fault Occurred.
Motor loading too high and/or
current not dropping below
175% FLA indicating that the
motor has not come up to
speed.
Abnormally low line voltage.
Initial current to low
Condition
Fault Occurred.
Control voltage absent.
D3 control board problem.
Condition
Loose connections.
Load actually not steady.
Other equipment on same
power feed causing power
fluctuations and/or distortion.
Condition
Phasing incorrect
Loose connections
Motor overloaded
Too many starts per hour
High ambient temperature
Acceleration time too long
Motor cooling
obstructed/damaged
Cause
See fault code troubleshooting table for
more details.
Reduce load on motor during starting.
Fix cause of low line voltage.
Increase initial current
Cause
See fault code troubleshooting table for
more details.
Check for proper control voltage input.
Verify wiring and fuses.
Consult McQuay Service.
Cause
Shut off all power and check all
connections.
Verify that the load is actually steady
and that there are not mechanical
issues.
Fix cause of power fluctuations and/or
distortion.
Cause
If input phasing correct, exchange any
two output wires.
If input phasing incorrect, exchange any
two input wires.
Shut off all power and check all
connections.
Reduce motor load.
Increase chiller LWT setpoint
deadband.
Reduce ambient temperature or provide
for better cooling.
Reduce starting load.
Remove cooling air obstructions. Check
motor cooling fan.
Solution
Solution
Solution
Solution
OM Centrif Micro ΙΙ-5