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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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01/25/21

Message Overview:

EQPT RACK TEMP HIGH
(Caution)

DDG Reference: None
Pilot Action (QRH): AVNC 02-6
System Description: 21-21-00
Schematic Diagram: 21-23-00
Wiring Diagram: 21-23-05

Message Description:

The amber 'EQUIPMENT RACK TEMP HIGH' caution CAS message indicates the temperature in either equipment rack is high.

  • The IASC has detected the rack temperature is above 158°F (70°C). Through ARINC bus to the DCU the EICAS has displayed the EQUIPMENT RACK TEMP HIGH message.
  • The indication can be verified through the MDC / IASC readings.

Pilot Action:

  • AFM 5-12-05

    • AIR SOURCE switch - NORM
    • COCKPIT COLD/HOT control - Full COLD
    • Land as soon as practical

  • Open the equipment rack door.

Possible Causes:

  • Avionics Rack Vent Temp Sensor 1 (MT39)
  • Avionics Rack Vent Temp Sensor 2 (MT30)
  • Integrated Air System Controller 1 (IASC 1) (A55 - FWD)
  • Integrated Air System Controller 2 (IASC 2) (A56 - AFT)

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Operational Test of the Avionics Cooling System AMM 21-23-00-710-801
Removal of the Equipment-Rack Vent Temperature-Sensor AMM 21-23-01-000-801
Installation of the Equipment-Rack Vent Temperature-Sensor AMM 21-23-01-400-801
Operational Test of the Cabin Pressure Control System AMM 21-31-00-710-801
Removal of the Integrated Air System (IAS) Controller AMM 21-31-01-000-801
Installation of the Integrated Air System (IAS) Controller AMM 21-31-01-400-801
Operational Test of the Integrated Air System (IAS) Controller AMM 21-31-01-710-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Determine if the condition is indication or an actual overheat condition.

    1. The equipment rack temperatures IASC #1 channel A indication is available through the LRU test page in the MDC. If the sensed temperature by the IASC is accurate, troubleshoot the fan and avionics valve. If the temperatures are inaccurate suspect the rack temperature sensor, it may require cleaning or replacement.
    2. IASC Equipment Rack LRU test pages.
    3. Cooling system adjustment and test IAW AMM 21-23-00-710-801.
    4. Removal/Installation of the Equipment Rack Vent Temp Sensor IAW AMM 21-23-01-000-801.

10_iasc_equip_rack_temp_sensor_status_pageequip_rack_cool_eicas

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