Message Name:

[ACSC1-B] LH PACK DISCH OVERHEAT

Message Code:

2162516ECS

The pack discharge temperature has been detected in an overheat condition.

• Pack Components/Ducting
• Air Cycle Machine (ACM)
• Pack Inlet Flow Sensor 1 (PIFS) (MT66)
• Pack Inlet Pressure Sensor 1 (PIPS) (MT65)
• Pack Discharge Temperature Sensor 1 (PDTS) (E27)
• Anti-Icing Pressure Sensor 1 (MT64)
• Left Air Conditioning System Controller (ACSC) (A87)
• Compressor Discharge Temperature sensor 1 (CDTS) (E25)
• Compressor Discharge Temperature sensor 2 (CDTS) (E31)
• Compressor Discharge Pressure sensor (CDPS)
• Associated Wiring

Advisory Wire/Service Bulletin:

• SB700-21-056 - Modification - Temperature Control -Replacement Of The Air-Conditioning System Controller (ACSC)
• SB700-1A11-21-030 - Modification - Temperature Control -Replacement of the Air-Conditioning System Controller (ACSC)

Full Throttle Blog/Forum Articles/Infoservice/Newsletter:

• Customer Forum-Newsletter 2016-01-05 Volume 13 issue 1 - Air Conditioning System - Intermittent “L-R Pack Fault” - Crew Alerting System (CAS) Messages
• Infoservice_Global_Oct_2006 - Air Conditioning System Troubleshooting

Flight Operation Notifications Manual (FONM): None

NOTES:

• When there is an overheat condition, the temperature indication for the pack discharge on the EICAS is an amber color.

1. Access CAIMS stored or active faults. If the following fault message is displayed, troubleshoot this message first.

   • 2162320ECS - [ACSC1-B] LH TEMP CONT VLV CMD /TCV

2. Make sure the aircraft is located in a hangar and was allowed sufficient time (a few hours) for the PACK temperature to reach ambient air temperature.
3. Measure and record the ambient air temperature in the aft equipment compartment [Outside Air Temperature (OAT)].
4. Access CAIMS. Select "SYSTEM DIAGNOSTICS" - ATA 21 - AIR CONDITIONING SYS CON 1A. Select "LRU TEST". Make a selection of "PACK Temp Sensor Data" and record the temperature values for the following sensors:

   Sensor	Indicated Temperature	Measured Ambient Temperature	Tolerance
   PACK INLET			±3 degree from OAT
   PACK (WATER EXTRACTOR)			±3 degree from OAT
   PACK DISCHARGE			±3 degree from OAT
   MIXING MANIFOLD			±3° from Cabin Temp

   NOTE: Pack Discharge may show 0 degree. Ok as long as temperature is not dashed.

   1. If there is a difference equal or greater than 3°C (5.4°F), troubleshoot the associated temp sensor.

      1. Pack Inlet temperature sensor
      2. Pack temperature sensor
      3. Pack Discharge temperature sensor
      4. Mix Manifold

   2. If the sensor temperature readings are the same as the measured ambient temperature, continue with next step.

5. Make sure that the anti-icing pressure sensor vent holes are not covered by the mounting clamps.
6. Access CAIMS. Select "SYSTEM DIAGNOSTICS" - ATA 21 - AIR CONDITIONING SYS CON 1A. Select "LRU TEST". Make a selection of "PACK Pressure XDCR Data" and record the pressure readings for the following sensors (Do the same with ACSC 2A):

   Sensor	Indicated Pressure ACSC 2B	Indicated Pressure ACSC 1B	Tolerance
   PACK INLET			<0.50 PSIA LH to RH
   PACK INLET FLOW (DP)			<0.0500 PSID LH to RH
   PACK DISCHARGE			<0.0500 PSID LH to RH

   1. If there is a sensor that is out of tolerance, troubleshoot the associated sensor.

      1. Pack Inlet Pressure Sensor
      2. Pack Inlet Flow Sensor
      3. Pack Discharge Pressure Sensor

   2. If the sensor pressure readings are within tolerance, continue with next step.

7. Interchange ACSC 1 with ACSC 2. Is the fault still present?

   1. If YES, continue with next step.
   2. If NO, replace defective ACSC.

8. Inspect the Pack Discharge Pressure Sensor (PDPS) sense line for damage, the presence of water or other obstruction.
9. Make sure that the PDPS pressure ports (three 0.052" dia. holes) are not covered by the supporting clamp installation.
10. Check the following lines and drains for damage or blockage: Air Cycle Machine (ACM) turbine, compressor, water extractor, water nozzle and PDPS Sense Line Drain.
    NOTE: When checking sense lines, ensure there are no cracks in flares of the couplings and that the couplings were properly torqued. It only takes a few drops of water to cause a problem. To purge the lines, they can be blown out with Nitrogen after removing the sensors.
11. Perform leak check of the Left Pack and ducting.

    1. If leaks are detected, rectify as required.
    2. If no leaks are detected, continue with next step.

12. Bring the A/C to a location where you will be able to run the APU. In the cockpit, make the following settings:

    1. PACK CONTROL switch to NORM.
    2. XBLEED switch to AUTO.
    3. APU BLEED switch to AUTO.
    4. L PACK and R PACK PBAs to OFF.

13. Pressurize the air conditioning system with the APU.
14. Push in the L PACK PBA.
15. In the Aft equipment compartment, make sure the Air Cycle Machine (ACM) does not make any unusual noises or vibrations. Check for airflow at the ram air outlet to make sure that the ACM rotates correctly.

    1. If the ACM makes unusual noises or vibrations or does not rotate correctly, replace the ACM.
    2. If the check is satisfactory, continue with next step.

16. Shut down the APU. Remove the left condenser/reheater unit. Attach an electronic torque wrench with an extension and an 11 mm socket to the turbine bolt head. Turn the shaft clockwise for no more than half a revolution while reading the torque value. Make sure the resistant torque value is ≤3.983 lbf/in (as per CMM 21-52-09.).

    1. If the resistant torque is out of tolerance, remove/replace the ACM and send for repair.
    2. If the torque value is good, continue with next step.

17. Interchange Pack Inlet Flow sensors. Is the fault still present?

    1. If YES, continue with next step.
    2. If NO, replace the defective PIFS.

18. Interchange Compressor Discharge Temperature sensors. Is the fault still present?

    1. If YES, continue with next step.
    2. If NO, replace the defective CDTS.

19. Interchange Compressor Discharge Pressure sensors. Is the fault still present?

    1. If YES, continue with next step.
    2. If NO, replace the defective CDPS.

20. Perform wiring checks of all wires between pack discharge temperature sensor and the ACSC.

    1. If defects are found, repair defective wiring as required.
    2. If no defects are found, continue with next step.

21. Perform wiring checks of all wires between pack discharge pressure sensor and the ACSC.

    1. If wiring defects are found, repair defective wiring as required and do close out.
    2. If no defects are found, continue with next step.

22. Perform the following troubleshooting.
23. Do close out.