Troubleshooting; Alarms; Table 4-1 Alarm Indications And Descriptions - Carrier EverFRESH Operation, Service And Parts Manual

4.1

Alarms

Alarm display is an independent controller software function. If an operating parameter is outside of the expected
range or a component does not return a valid signal back to the controller, an alarm is generated. The
®
EverFRESH Controlled Atmosphere option alarms are AL907, AL909, AL910, AL929, AL962, AL976, AL977,
AL978, AL979, AL980, and AL981. For units configured with the CO2 Injection option, additional alarms AL982 and
AL983 are available.
AL907 Manual Fresh Air Vent Open
Cause: For units equipped with EverFRESH and a Vent Position Sensor (VPS), the controller will monitor the
manual fresh air opening at a pre-determined time. If during this time the manual fresh air vent is open
and EverFRESH is active, an alarm will be generated. If alarm is active, the controller monitors the
manual fresh air once per hour. Upon clearing the alarm, the controller goes back to monitoring at
the pre-determined time.
Component Vent Position Sensor (VPS)
Troubleshooting Manually reposition the vent to 0% and confirm using Cd45. If Cd45 is not
AL909 O2 Sensor Fault
Cause: Triggered anytime the O2 sensor reading is outside of the normal operation range, after an initial
signal was detected.
Action: EverFRESH Air Compressor (EAC) 100% duty cycle and open the EverFRESH Air Valve (EA). Will
prevent low O2 and cargo loss. If both AL909 and AL910 are active, run the EAC and open the EA.
Component O2 Sensor, O2 Amplifier
Troubleshooting Check Cd44 and scroll down to 02V. The O2 sensor output will be displayed
Section 4

Troubleshooting

Table 4–1 Alarm Indications and Descriptions
reading 0%, perform a calibration of the panel.
If a zero reading cannot be obtained, replace the defective VPS.
If the unit is loaded, ensure the vent is closed. Note and replace the VPS on
the next PTI. The alarm will not affect the EverFRESH system from operating.
in millivolts (130mV to 4100mV is good range).
Check wiring (refer to schematic), and check for bad connections or wires
positioned improperly.
If the O2 sensor is available, remove the upper fresh air panel and evaporator
motor and replace the sensor. If after replacing the sensor Cd44 reads outside
of the normal range and AL909 continues, replace the amplifier.
If parts are not available, turn the EverFRESH option off via Cd71 and open
the manual fresh air vent.
4–1 T-374