Table 3-6 Controller Alarm Indications - Carrier 69NT40--541--200 TO 299 Operation And Service

Code
TITLE
No.
Evaporator Motor 1
AL11
IP Trip
Evaporator Motor 2
AL12
IP Trip
Control Circuit Fuse
AL20
Open (24 vac)
Micro Circuit Fuse
AL21
Open (18 vac)
Evaporator Fan Mo-
AL22
tor Safety
Compressor Motor
AL24
Safety
Condenser Fan Mo-
AL25
tor Safety
All Supply and Re-
turn temperature
AL26
Control Sensors
Failure
Probe Circuit Cal-
AL27
ibration Failure
Fresh Air Position
AL50
Sensor (VPS)
AL51 Alarm List Failure
AL52 Alarm List Full
AL53 Battery Pack Failure
T-317
Table 3-6 Controller Alarm Indications (Sheet 1 of 3)
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 pro-
tector opens. If the alarm is active, probe check is deactivated.
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 pro-
tector opens. If the alarm is active, probe check is deactivated.
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.
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.
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.
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.
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 is deactivated if the unit
is operating on water cooled condensing.
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.
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 converter.
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.
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 generate an alarm event. The alarm is trig-
gered off when the unit power cycles and the sensor is within valid range.
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 in-
volving alarm list activity that results in an error will cause Alarm 51 to be acti-
vated. 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.
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.
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
DESCRIPTION
3-18