Carrier 69NT40-541-306 Operation And Service Download

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T-354

4–24

AL22

Evaporator Fan
Motor Safety

Alarm 22 responds to the evaporator motor internal protectors. On units with Nor-
mal Evaporator Fan Operation (CnF32 set to 2EFO) the alarm is triggered by
opening of either internal protector. It will disable all control units until the motor
protector resets. On units with Single Evaporator Fan Capability (CnF32 set to
1EFO), the alarm is triggered by opening of both internal protectors. It will disable
all control units until a motor protector resets.

AL24

Compressor
Motor Safety

Alarm 24 is triggered by the opening of the compressor motor internal protector.
This alarm will disable all control units except for the evaporator fans and will re
main active until the motor protector resets. This alarm triggers the failure action
code set by Function Code Cd29.

AL25

Condenser Fan
Motor Safety

Alarm 25 is triggered by the opening of the condenser motor internal protector
and will disable all control units except for the evaporator fans. This alarm will re-
main active until the motor protector resets. This alarm is deactivated if the unit is
operating on water cooled condensing.

AL26

All Supply and Return
Temperature Control
Sensors Failure

Alarm 26 is triggered if the Controller determines that all of the control sensors
are out-of-range. This can occur for box temperatures outside the range of -50



to +70



C (-58



F to +158



F). This alarm triggers the failure action code set by

Function Code Cd29.

AL27

Probe Circuit
Calibration Failure

The Controller has a built-in Analog to Digital (A-D) converter, used to convert an-
alog readings (i.e. temperature sensors, current sensors, etc.) to digital readings.
The Controller continuously performs calibration tests on the A-D converter. If the
A-D converter fails to calibrate for 30 consecutive seconds, this alarm is activat-
ed.This alarm will be inactivated as soon as the A-D converter calibrates.

AL29 AutoFresh Failure

Alarm 29 is triggered if CO2 or O2 level is outside of the limit range and the vent
position is at 100% for longer than 90 minutes. Alarm LED will be activated and
user intervention is required. The alarm is triggered off when atmospheric condi-
tions are within limit settings.

AL50

Fresh Air Position
Sensor (VPS)

Alarm 50 is activated whenever the sensor is outside the valid range. There is a
five minute adjustment period where the user can change the vent position with
out generating an alarm event. The sensor requires five minutes of no movement
to confirm stability. If the vent position changes at any point beyond the five min-
ute adjustment period, the sensor will generate an alarm event. The alarm is trig-
gered off when the unit power cycles and the sensor is within valid range.

AL51 Alarm List Failure

During start-up diagnostics, the EEPROM is examined to determine validity of its

contents. This is done by testing the set point and the alarm list. If the contents

are invalid, Alarm 51 is activated.
During control processing, any operation involving alarm list activity that results

in an error will cause Alarm 51 to be activated. Alarm 51 is a “display only” alarm

and is not written into the alarm list.
Pressing the ENTER

key when “CLEAr” is displayed will result in an attempt to

clear the alarm list. If that action is successful (all alarms are inactive), Alarm 51

will be reset.

AL52 Alarm List Full

Alarm 52 is activated whenever the alarm list is determined to be full; at start-up
or after recording an alarm in the list. Alarm 52 is displayed, but is not recorded
in the alarm list. This alarm can be reset by clearing the alarm list. This can be
done only if all alarms written in the list are inactive.

AL53 Battery Pack Failure

Alarm 53 is caused by the battery pack charge being too low to provide sufficient

power for battery-backed recording. Renew replaceable batteries.
If this alarm occurs on start up, allow a unit fitted with rechargeable batteries to

operate for up to 24 hours to charge rechargeable batteries sufficiently to deacti-

vate the alarm

Table 4–6 Controller Alarm Indications (Continued)

CODE

TITLE

DESCRIPTION