R PACK TEMP
(Caution)

The pack discharge temperature is out of range when the flow control valve is not closed and there is no R PACK FAIL message.

• PACK Discharge Pressure Sensor (PDPS) 2 (MT107)
• Air Cycle Machine (ACM)
• HOT/COLD Toggle Switch (S4)
• BLEED AIR Control Panel (AP8)
• Air-Conditioning System Controller (ACSC) 2 (A88)
• Associated Wiring

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Using the PMAT, access CAIMS active and stored faults. Are there any air conditioning (ATA 21) related fault messages?

   1. If YES, troubleshoot these messages first using SmartFix Plus CAIMS troubleshooting pages.
   2. If NO, continue with next step.

2. Make sure the aircraft is parked inside away from direct sunlight and has been allowed to reach ambient temperature before continuing with next step.
3. Access CAIMS System Diagnostics. Select ATA 21, ACSC 1A, LRU TEST and select L ACSC CH.A PACK TEMP SENSOR DATA. Record the data on the ECS Data Table. Repeat for ACSC 1B, 2A and 2B.
4. To record all of the data you will also need to look at ATA 36, BMC 1(2), L BMC DISCRETE & ANALOG INPUT DATA.
5. Follow the instructions comprised in the Pack Discharge Temperature Split troubleshooting document.

   1. If the root cause of the issue has been identified and rectified, do close out.
   2. If the issue persists, continue with next step.

6. Swap ACSC 2 (A88) with ACSC 1 (A87). Is the fault still present on the same side?

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

7. On the BLEED AIR control panel, perform a continuity checks of HOT/COLD toggle switch as follows:
   

   HOT/COLD toggle switch position	From	To	Expected result	Result
   COLD position	AP8J2-25	AP8J2-3	Continuity
   COLD position	AP8J2-26	AP8J2-3	Open
   HOT position	AP8J2-25	AP8J2-3	Continuity
   HOT position	AP8J2-26	AP8J2-3	Open

   1. If the toggle switch operates as per table above, continue with next step.
   2. If the toggle switch is found faulty, replace the HOT/COLD toggle switch and do close out.

8. Remove ACSC 2 (A88) and perform a continuity check from the BLEED AIR control panel aircraft-side connector as follows:
   

   From	To	Result
   AP8P2-25	Ground
   AP8P2-26	Ground

   1. If there is continuity, repair defective wiring as required and do close out.
   2. If there is no continuity, continue with next step.

9. Replace BLEED AIR control panel. Is the fault still present?

   1. If YES, contact the Bombardier Customer Response Center and provide the ECS Data Table previously populated for further assistance.
   2. If NO, continue with next step.

10. Do close out.