AIR COND TEMP HIGH
(Caution)

The amber 'AIR COND TEMP HIGH' caution CAS message indicates excessive air temperature has been sensed in the cabin or cockpit air distribution duct.

• The cockpit duct temperature is higher than 185°F (85°C) for longer than 30 seconds, will post the fault.
• The cabin duct temperature is higher than 185°F (85°C) for longer than 30 seconds, will post the fault.
• The system uses single sensors with dual elements, the cockpit duct sensor A channel monitored by IASC #1, B channel by IASC #2, cabin duct sensor both A and B are monitored by IASC #2.

NOTE: This procedure can be used for insufficient pack cooling performance.

• Temperature Control Valve (TCV) (MPE7)
• Cabin Duct Temp Sensor (Cabin DTS) ( MT26)
• Cockpit Duct Temp Sensor (Cockpit DTS) (MT35)
• Integrated Air System Controller 1 (IASC 1) (A55 - FWD)
• Air Cycle Machine (ACM)

Advisory Wire/Service Bulletin:

• AW300-21-0264 - ACM Failures Caused by Ram Air Circuit Blockage

Forum Articles/Infoservice/Newsletter: None

1. Duplicate or verify air conditioning system operation IAW AMM 21-52-00-710-801.
2. Troubleshoot if posted an amber 'TRIM AIR FAIL' CAS message first.
3. Select the AIR SOURCE switch OFF.
4. From MDC main menu, go to LRU Test and IASC test 1a.
5. In the Air Conditioning Raw Data section, pick AIR COND VALVE STATUS.
6. Ensure the Temp Control Valve is saying both Not Open and Closed.
7. Select AIR SOURCE to NORM or PACK ONLY.
   

   

   PACK ONLY MODE

8. From the LRU Test/IASC test 1a, Air Cond Raw Data, Bleed Valve Status, ensure the FLOW CTRL VALVE 1 is NOT Full Closed and CMD is ENABLE.
9. Monitor the Temp Control Valve and ensure it stays closed. (it may modulate initially, but should eventually go closed.)
10. If the TCV is closed and heat is coming from the pack, there is a good chance the ACM is seized or otherwise blowing hot air.
11. From LRU Test, IASC test 1a, Air Cond Raw Data, select TEMPERATURE SENSORS STATUS and monitor the PACK TEMPERATURE.
12. If the pack temp exceeds 50°C and obviously getting hotter and the TCV is closed, the ACM is not making cold air.
13. If there is no exhaust air coming from the PACK exhaust outlet, the ACM is seized. If the ACM is seized check the plenum for particles of the Ozone filter. Inspect the #1 and #2 Ozone Filters to ensure they are intact and not coming apart. If the #1 Ozone Filter is coming apart it will cause damage to the ACM, Pre Cooler and Heat Exchanger.
14. If exhaust outlet air is present, and the pack temp appears to be just high, check the dual heat exchanger for contamination, there are three ways to inspect the top of the heat exchanger:
    

    

    Dual Heat Exchanger

    1. Remove the 20 bolts that hold the Lower Ram Air Intake Ducting in place on the Heat Exchanger and perform a visual inspection of the inlet.
    2. Borescope the ram air inlet with the appropriate length borescope.
    3. Loosen the clamps and remove the boot shown in the photograph to facilitate a visual inspection.

15. Verify the water spray is operating properly. Disconnect the aspirator feed line from the water extractor, check the line for contamination and slight vacuum with the air conditioning system running. Clean, unclog or repair as required.
    

    

    Water Spray

16. While unlikely, if the temperature is cool, the problem could be due to a dual channel failure of the cockpit or duct temperature sensor. The sensor temperature readings are displayed on the IASC LRU test pages in the MDC. Check for the sensor reading out of tolerance/high, verify wiring per AWM 21-61-29 and replace. Typically only one channel at a time will fail causing a cyan 'AIR COND FAULT'.

Select an MDC Fault Code/Message:B3-006360 - TRIM AIR SUPPLY OVERHEAT [AIR SUPPLY OVHT]