Carrier 69NT40-489-100 Series, Operation And Service Manual

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105
T-305
Table 24. CA Controller Alarm Indications
CODE
NO.
TITLE DESCRIPTION
AL30 Control Contactor Fuse Open (24 vac)
Alarm 30 is triggered by fuse (F3) opening, which causes
software shutdown of all control units. This alarm will remain
active until the 10 amp fuse is replaced.
AL31 Control Circuit Fuse Open (18 vac)
Alarm 31 is triggered by one of the fuses (F1 or F2) being
opened on the 18 volt AC power supply to the CA Controller.
AL32 Air Compressor Safety
Alarm 32 is triggered by the opening of the air compressor
motor internal protector (IP-AM). This alarm will disable all
control units until the motor protector resets. The carbon
dioxide solenoid valve (CSV) and the sample air solenoid
valve (SAV) will continue to be energized when the source is
available and required.
AL33 Not used
AL34 Oxygen Sensor Failure
Alarm 34 is triggered by an out of range condition (less than
0% or greater than 25%). This alarm will remain active until
the sensor is in-range. While AL34 is active, the compressor
will run with the oxygen solenoid valve (OSV) open, unless
AL39 is active, whereby all control units will be disabled,
except the sample air solenoid valve (SAV).
AL35 Carbon Dioxide Sensor Failure
Alarm 35 is triggered by the voltage output being out of range
(less than 0.95v or greater than 5.05v) for 30 minutes, or ten
unsuccessful automatic calibration attempts. This alarm will
remain active until the sensor is in-range or a successful
carbon dioxide (CO
2)
zero calibration is performed.
AL36 A/D Converter Failure
The CA Controller has a built-in A-D (Analog to Digital)
converter, used to convert analog readings (i.e. gas sensors,
pressure sensors, etc.) to digital readings. The CA 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 and will result in disabling all
control units. This alarm will be inactivated upon a successful
A-D converter calibration.
AL37 Communication Error
Alarm 37 is triggered when there is a loss of communication
with the Temperature (refrigeration) Controller. This alarm will
be inactivated as soon as communication is established or the
system is reset.
AL38
Membrane Temperature Sensor
Failure
Alarm 38 is triggered by an out of range condition of the
membrane temperature sensor (MTS). This alarm will be
inactivated when in-range or the system is reset.
AL39 Oxygen Solenoid Valve Failure
Alarm 39 is triggered by a malfunction of the oxygen solenoid
valve (OSV). It can be activated in control mode as described
below or upon failure of pre-trip step P1-1. Pressure at the
membrane temperature sensor (MPT) is measured before and
after the oxygen solenoid valve (OSV) opens. The pressure
drop must be greater than 20 psig or the alarm will activate. If
AL47 is active, two measurements of oxygen (O
2
) percentage
will be taken one hour apart. If the O
2
percentage has not
increased by more than a fixed value the alarm (AL39) will
activate. This is a partial shutdown alarm, and will only
prevent the compressor from energizing during a demand for
O
2
levels to increase.
AL40 Heater Control Failure
Alarm 40 is triggered by failure of the air temperature to reach
set point (+0
°
C/--3
°
C) within two hours of operation. This is a
display alarm, which indicates a possible heater failure.