7. Troubleshooting
7.1. Alarms and warnings
7.1.1. Alarms and warnings
A warning or an alarm is signaled by the relevant LED on the front of the adjustable frequency
drive, and indicated by a code on the display.
A warning remains active until its cause is no longer present. Under certain circumstances, oper-
ation of the motor may still be continued. Warning messages may be critical, but are not
necessarily so.
In the event of an alarm, the adjustable frequency drive will have tripped. Alarms must be reset
to restart operation once their cause has been rectified. This may be done in four ways:
1. By using the [RESET] control button on the LCP control panel.
2. Via a digital input with the “Reset” function.
3. Via serial communication/optional serial communication bus.
4. By automatically resetting using the [Auto Reset] function, which is a default setting for
the VLT HVAC Drive; see
par. 14-20 Reset Mode
in
VLT
®
HVAC Drive Programming Guide,
MG.11Cx.yy
NOTE
After a manual reset using the [RESET] button on the LCP, the [AUTO ON] button
must be pressed to restart the motor.
If an alarm cannot be reset, the reason may be that its cause has not been rectified, or that the
alarm is trip-locked (see also the table on following page).
Alarms that are trip-locked offer additional protection; this means that the line supply must be
switched off before the alarm can be reset. After being switched back on, the adjustable frequency
drive is no longer blocked and may be reset as described above, once the cause has been rectified.
Alarms that are not trip-locked can also be reset using the automatic reset function in parameter
14-20 (Warning: automatic wake-up is possible!)
If a warning and alarm is marked against a code in the table on the following page, this means
that either a warning occurs before an alarm, or that it can be specified whether it is a warning
or an alarm that is to be displayed for a given fault.
This is possible, for instance, in parameter 1-90
Motor Thermal Protection.
After an alarm or trip,
the motor carries on coasting, and the alarm and warning flash on the adjustable frequency drive.
Once the problem has been rectified, only the alarm continues flashing.
VLT
®
HVAC Drive Instruction Manual 7. Troubleshooting
MG.11.A4.22 - VLT
®
is a registered Danfoss trademark
131
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