Troubleshooting; Alarms And Alerts; Resetting Alarms; Alarm History - Carrier 38APS025 Manual

TROUBLESHOOTING

Table 78 is an abbreviated list of symptoms, probable
causes, and potential remedies.
Alarms and Alerts —
or fault conditions, and may cause either one circuit or the
whole unit to shut down. They are assigned code numbers as
listed in Table 79. Active pre-alerts/alerts/alarms are shown in
Currently Active Alarms, Alarms CRNT. Up to 20 current
alarms will be displayed. Pressing
buttons simultaneously will expand the alarm code description
only. Time and date stamps are available in Alarm History.
If the unit is in alarm and unable to operate, Control Mode
will show Run Status VIEW STAT=4 (Off Emrgcy). Au-
tomatic alarms will reset without operator intervention if the
condition corrects itself. Manual alarms will require operator
intervention to reset the alarm.
SYMPTOM
Unit does not run
Unit runs when it is not called for
Unit operates too long or continuously
Circuit does not run
Circuit does not load
Compressor does not run
These are warnings of abnormal
and
ENTER
ESCAPE
Table 78 — Troubleshooting
POSSIBLE CAUSES
Check for power to unit
Wrong/incorrect unit configuration
Active alarm
Active operating mode
No cooling load
Incorrect unit configuration
Low refrigerant charge
Compressor or control contacts welded
Non-condensables in refrigerant circuit
Active alarm
Active operating mode
Active alarm
Active operating mode
Low Saturated Suction Temperature
Faulty compressor discharge check-valve
Active alarm
Active operating mode
Inoperative compressor contactor
RESETTING ALARMS — Before resetting any alarm, first
determine the cause of the alarm and correct it. After determin-
ing and correcting the cause of the alarm, toggle
Alarms RCRN (Reset All Current Alarms) from NO to
YES. The control may prompt the user for a password, by dis-
playing PASS and WORD. See Configuration and Service
Password on page 22 for information on the password. If the
condition has been resolved, the alerts/alarms will be cleared
from the active alert/alarm set.
ALARM HISTORY — The scrolling marquee and Naviga-
tor display have the ability to display the latest alarms and
™
alerts up to 20 events. This is a first-in, first-out alarm buffer.
As a Pre-alert, Alert, or Alarm is generated, it is written to the
Alarm History. To access Alarm History, enter Alarms HIST.
Use the arrow keys to move through the history. The latest pre-
alerts, alerts and alarms will appear first on the list. Pressing
and
ENTER
ESCAPE
and date stamp and expand the pre-alert/alert/alarm code.
Check overcurrent protection device.
Check non-fused disconnect (if equipped).
Restore power to unit.
Check for 24 volts at the control boards.
Check unit configuration.
If unit is controlled by a Local Schedule, check to
be sure that the Day of the Week is properly set.
Enable-Off-Remote Switch is not in a position to
allow the unit to operate.
Fan Status Switch is open.
Check alarm status. See Alarms and Alerts begin-
ning on page 162 and follow troubleshooting
instructions.
Check for Operating Modes. See the Operating
Modes section beginning on page 135 and follow
troubleshooting instructions.
Cooling Load is satisfied.
If unit is controlled by a Local Schedule, check to
be sure that the Day of the Week is properly set.
Check for leak and add refrigerant.
Replace contactor or relay.
Remove refrigerant and recharge.
Check alarm status. See Alarms and Alerts begin-
ning on page 162 and follow troubleshooting
instructions.
Check for Operating Modes. See the Operating
Modes section beginning on page 135 and follow
troubleshooting instructions.
Check alarm status. See Alarms and Alerts begin-
ning on page 162 and follow troubleshooting
instructions.
Check for Operating Modes. See the Operating
Modes section beginning on page 135 and follow
troubleshooting instructions.
See Alarms, Pre-Alerts, and Alerts A120, A121,
P120,121, T120,121, page 168.
Replace compressor.
Check alarm status. See Alarms and Alerts begin-
ning on page 162 and follow troubleshooting
instructions.
Check for Operating Modes. See the Operating
Modes section beginning on page 135 and follow
troubleshooting instructions.
Check control wiring.
Check contactor operation, replace if necessary.
162
simultaneously will provide a time
POSSIBLE REMEDIES