Carrier Streamline Scroll 69NT20-531-300 - Manual (Page 43)

3-18 T-309
Table 3-6 Controller Alarm Indications (Sheet 2 of 4)
AL25 Condenser Fan Mo-
tor 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
remain active until the motor protector resets. This alarm triggers failure action
C (evaporator fan only) or D (all machinery off) of Function Code Cd29 if the
unit has a perishable set point. Failure action D (all machinery off) is triggered if
the unit has a frozen set point
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 A/D Accuracy Fail-
ure
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 read-
ings. The Controller continuously performs calibration tests on the A-D con-
verter. If the A-D converter fails to calibrate for 30 consecutive seconds, this
alarm is activated.This alarm will be inactivated as soon as the A-D converter
calibrates.
AL28 Low Suction Pres-
sure
Alarm 28 is triggered if suction pressure is below 2 psia and alarm 66 (Suction
Pressure Transducer Failure) is not active. This alarm will be inactivated when
suction pressure rises above 2 psia for three continuous minutes. This alarm trig-
gers failure action C (evaporator fan only) or D (all machinery off) as determined
by User Selectable Failure Response if the unit has a perishable set point; Failure
action D (all machinery off) if the unit has a frozen set point. Reset SMV.
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 con-
tents 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 ac-
tivated. 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 deactivate the alarm
AL54
Primary Supply
Temperature Sensor
Failure (STS)
Alarm 54 is activated by an invalid primary supply temperature sensor reading
that is sensed outside the range of --50 to +70_C (--58_F to +158_F) or if the
probe check logic has determined there is a fault with this sensor. If Alarm 54 is
activated and the primary supply is the control sensor, the secondary supply sen-
sor will be used for control if the unit is so equipped. If the unit does not have a
secondary supply temperature sensor, and AL54 is activated, the primary return
sensor reading, minus 2_C will be used for control.
NOTE
The P5 Pre-Trip test must be run to inactivate the alarm
AL55 DataCORDER
Failure
This alarm activates to indicate the DataCORDER has a software failure. To
clear this alarm, reconfigure the unit to the current model number. This failure
may be the result of a voltage dip in access of 25%.