Carrier EverFRESH Operation, Service And Parts Manual page 26

AL910 CO2 Sensor Fault
Cause: Triggered anytime the CO2 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 CO2 Sensor
Troubleshooting Check wiring (refer to schematic), and check for bad connections or wires
AL929 Loss of Atmospheric Control
Cause: Triggered whenever the CO2 level is above its setpoint by 2%. Or, when the O2 level is below its
setpoint for longer than 30 minutes. The alarm is triggered off when the levels return to within the
normal range.
Action: Enable Alarm LED. Open the fresh air vent and air compressor is enabled.
Troubleshooting If a component is not functioning properly, it will fail the appropriate P-20 sub
Component Membrane Pressure Transducer (MPT)
Troubleshooting Remove the MPT. Turn on the container unit. Using Cd44, verify the MPT
Component EverFRESH Air Compressor (EAC)
Troubleshooting Verify EAC fuses FEF1, FEF2 & FEF3.
Component EverFRESH Air Valve (EA)
Troubleshooting A closed or plugged EA solenoid could prevent fresh air from entering the
T-374
Table 4–1 Alarm Indications and Descriptions
positioned improperly.
Check the voltage on the back of MD connectors pin MD09 (-) and MD03 (+12
VDC) with the controller energized. If 12 VDC is not available, check the
controller. If 12 VDC is available, check the back of pin MD02 for a voltage
between 1.0 - 4.7 VDC. If not present, replace the sensor.
If a sensor is available, remove the upper fresh air panel and evaporator motor
and replace the sensor. If no part is available, take no action and service at
the next PTI.
Setup Verify all EverFRESH components are functioning properly by checking for
EverFRESH alarms and running a P-20 Pre-Trip.
test. Note components in order below.
pressure reads between -5 psig and 5 psig. Outside this range, or if AL977 is
active, replace the sensor.
Check P20 results for a failure mode:
• Possible detected failure with EAC current consumption, check com-
pressor motor windings, and verify voltage on all 3 phases.
• MPT failure. Follow steps above.
• Failure of AC contactor for EAC. Ohm contactor coil and check resis-
tance across contactor legs, with power removed.
container. P20-2 tests the valve.
Potential failure results:
• MPT pressure fails to change when the valve is energized. Check for
signs of blockage in the valve or piping.
• EA current is not correct. Access function code Cd74 and perform a
ML5 self-check to verify the controller is functioning properly. If it
passes, perform an ohm check between the CA08 pin and TRX2
(ground) using the carrier service tool (part # 22-50485-00).
4–2