EQPT RACK COOL FAULT
(Advisory)

The cyan 'EQPT RACK COOL FAULT' advisory CAS message indicates a fault has been detected in the avionics equipment rack cooling system.

• The Integrated Air System Controller (IASC) handles all failures of the system automatically. The IASC 1 is the primary controller (normal operation) and IASC 2 ensures the backup control mode (degraded mode).
• In normal operation, the AVFAN is operated when the aircraft altitude is lower than 25,000 ft or during descent phase. The fan is normally operated at high speed. It operates at a low speed in case of a single bleed operation. Above 25,000 ft, the AV is opened and the fan is switched off.
• The transition from respectively fan to valve or valve to fan begins with fan shut-off or valve closure.

• Avionics Cooling Fan (AVFAN) (B3)
• Avionics Cooling Valve (MPE14)
• Ventilated Temperature Sensor (VENTS) (MT39)
• Integrated Air System Controller 1 (IASC 1) (A55 - FWD)
• Integrated Air System Controller 2 (IASC 2) (A56 - AFT)

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

NOTE:

• If no rotation from the avionics cooling fan (B3) is sensed within 10 seconds,the avionics cooling valve (MPE14) in the belly goes to open and all power is lost at the avionics cooling fan motor.. Therefore, no voltage at stud T14 and T15 after 10 seconds. So, the avionics cooling fan (B3) is faulty.

1. Determine when the condition had happened, in flight above 25,000 ft or below.

   1. Below 25,000 ft a fan failure is detected by low rotational speed generating a discrete output to the IASC, or the avionics cooling valve is not closed. Above 25,000 ft the valve should be open with the fan off. Position switches on the valve provide discrete outputs to the IASC for position verification.
   2. Select the MDC fault or equation from the drop down below to provide additional information to assist in troubleshooting.
      Select an MDC Fault Code/Message:B3-006371 - FAILED OFF [AVIONICS FAN]B3-006372 - DISAGREE / VALVE CLOSED [AVIONICS VALVE]B3-006373 - DISAGREE / VALVE OPEN [AVIONICS VALVE]B3-006374 - CH A&B FAULT [AVIONICS T SNSR1]B3-006375 - CH A FAULT [AVIONICS T SNSR1]B3-006376 - CH B FAULT [AVIONICS T SNSR1]B3-006377 - CH A&B FAULT [AVIONICS T SNSR2]B3-006378 - CH A FAULT [AVIONICS T SNSR2]B3-006379 - CH B FAULT [AVIONICS T SNSR2]