Carrier 69NT40-541-001, Operation And Service

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4–23 T-316
Table 4–6 Controller Alarm Indications
CODE # TITLE DESCRIPTION
AL11 Evaporator Motor 1 IP Trip
Alarm 11 is applicable to units with Single Evaporator Fan Capability
(CnF32 set to 1EFO) only. The alarm is triggered if the evaporator fan
motor #1 internal protector opens. If the alarm is active, probe check is
deactivated.
AL12 Evaporator Motor 2 IP Trip
Alarm 12 is applicable to units with Single Evaporator Fan Capability
(CnF32 set to 1EFO) only. The alarm is triggered if the evaporator fan
motor #2 internal protector opens. If the alarm is active, probe check is
deactivated.
AL20
Control Circuit Fuse Open (24
vac)
Alarm 20 is triggered by control power fuse (F3A, F3B) opening and will
cause the software shutdown of all control units. This alarm will remain
active until the fuse is replaced.
AL21
Micro Circuit Fuse Open (18
vac)
Alarm 21 is triggered by one of the fuses (F1/F2) being opened on 18
volts AC power supply to the Controller. The suction modulation valve
(SMV) will be opened and current limiting is halted. Temperature control
will be maintained by cycling the compressor.
AL22 Evaporator Fan Mo tor Safety
Alarm 22 responds to the evaporator motor internal protectors. On units
with Normal Evaporator Fan Operation (CnF32 set to 2EFO) the alarm
is triggered by opening of either internal protector. It will disable all con-
trol 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 pro-
tector 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 evapora-
tor 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 Mo tor Safety
Alarm 25 is triggered by the opening of the condenser motor internal pro-
tector and will disable all control units except for the evaporator fans.
This alarm will remain active until the motor protector resets. This alarm
is deactivated if the unit is operating on water-cooled condensing.
AL26
All Supply and Re turn
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°C 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 analog 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 activated. This alarm will be inactivat-
ed as soon as the A-D converter calibrates.
AL50
Fresh Air Position Sensor
(VPS)
Alarm 50 is activated whenever the sensor is outside the valid range.
There is a 5 minute adjustment period where the user can change the
vent position without generating an alarm event. The sensor requires 5
minutes of no movement to confirm stability. If the vent position changes
at any point beyond the 5 minute adjustment period, the sensor will gen-
erate an alarm event. The alarm is triggered off when the unit power cy-
cles and the sensor is within valid range.