W DOC AIRBUS | TSM A320F

Failure of the Blower Fan

TASK 21-26-00-810-809-A
Failure of the Blower Fan

1. Possible Causes
  • CNTOR-BLOWER FAN CTL, AVNCS VENT (8HQ)
  • FAN-BLOWER, AVNCS VENT [20HQ]
  • C/B-AVNCS VENT/BLOWER/FAN [1HQ]
  • CARTRIDGE-AVNCS VENT FILTER [2082HM]
  • AEVC [10HQ]
  • wiring
  • C/B-AIR COND/AVNCS/VENT/MONG [3HQ]
  • PRESS SW-BLOWER FAN, AVNCS VENT [17HQ]
  • PRESS SW-BLOWER FAN, AVNCS VENT [19HQ]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 24-00-00-810-803-A
Circuit Breaker Tripped and/or C/B TRIPPED Warning
AMM 21-26-00-710-001
Operational Check of the Avionics Equipment Ventilation-System via MCDU
AMM 21-26-00-710-008
Operational Test to Read the CFDS for CLASS 3 Faults of the AEVC
AMM 21-26-00-710-009
Operational Test to Read the CFDS for LAST LEG REPORT of the AEVC
ASM 212603
AMM 21-26-11-000-001
Removal of the Blower and Extract Fan Pressure Switches
AMM 21-26-11-400-001
Installation of the Blower and Extract Fan Pressure Switches
AMM 21-26-34-000-001
Removal of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-34-400-001
Installation of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-43-920-001
Discard the Filter Cartridge (PALL)
AMM 21-26-51-000-001
Removal of the Extract and Blower Fans
AMM 21-26-51-400-001
Installation of the Extract and Blower Fans
3. Fault Confirmation
Subtask 21-26-00-865-053-A
A. Table of the circuit breakers used in this procedure:
PANELDESIGNATIONFINLOCATION
** ON A/C ALL
122VUAIR COND/AVNCS/VENT/MONG3HQY17
123VUAVNCS VENT/BLOWER/FAN1HQAD10
Subtask 21-26-00-710-090-A
B. Test
   (1) Do the reset of the AEVC (10HQ).
     (a) Open the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
     (b) Wait for five seconds.
     (c) Close the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
   (2) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
   (3) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
   (4) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.
4. Fault Isolation
Subtask 21-26-00-810-072-D
A. If the test gives the maintenance message BLOWER FAN 20HQ:
  • Make sure that the avionics ventilation filter is clean.
   (1) If the AVNCS VENT/BLOWER/FAN circuit breaker (1HQ) is open:
     (a) If the fault continues:
  • Replace CNTOR-BLOWER FAN CTL, AVNCS VENT (8HQ).
     (b) If the fault continues:
     (c) If the fault continues:
  • Replace C/B-AVNCS VENT/BLOWER/FAN [1HQ] .
   (2) If the avionics ventilation filter is dirty:
   (3) If the avionics ventilation filter is clean:
   (4) If the fault continues:
   (5) If the fault continues:
  • Do a check of the status of the AVNCS VENT/BLOWER/FAN circuit breaker (1HQ).
   (6) If the AVNCS VENT/BLOWER/FAN circuit breaker (1HQ) is closed:
  • Do a check for 115VAC at pins A/J, A/K and A/L of the blower fan (20HQ).
     (a) If there is no 115VAC:
  • Do a check for 115VAC at pins T1, T2 and T3 of the blower fan control-contactor (8HQ).
       1 If there is no 115VAC:
  • Do a check of the wiring ASM 212603 between:
    . the blower fan control-contactor (8HQ), pins L1, L2 and L3 and the circuit breaker (1HQ), pins A2, B2 and C2.
         a If the wiring is not correct:
  • Repair the related wiring.
         b If the wiring is correct:
  • Replace C/B-AVNCS VENT/BLOWER/FAN [1HQ]
       2 If there is 115VAC:
  • Do a check of the status of the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ).
         a If the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ) is closed:
  • Do a check for 28VDC at pin A/E of the blower fan (20HQ).

    * If there is no 28VDC:
    * - Do a check of the wiring ASM 212603 between:
    * . The blower fan (20HQ) pin A/E and the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ)
    * . The blower fan (20HQ) pin A/F and the ground.

    ** If the wiring is not correct:
    ** - Repair the related wiring.

    ** If the wiring is correct:
    ** - Replace C/B-AIR COND/AVNCS/VENT/MONG [3HQ] .

    * If there is 28VDC:
    * - Make sure that the warning light of the blower fan (20HQ) is off.

    ** If the warning light is on, push the RESET pushbutton switch on the blower fan (20HQ).
NOTE: The fan starts immediately.
The warning light goes off.
** If the fault continues:
** - Replace FAN-BLOWER, AVNCS VENT [20HQ] AMM 21-26-51-000-001 and AMM 21-26-51-400-001.

** If the fault continues:
** - Do a check for 28VDC at pin AA/8A of the AEVC (10HQ) ASM 212603.

*** If there is 28VDC:
*** - Replace AEVC [10HQ] AMM 21-26-34-000-001 and AMM 21-26-34-400-001.

*** If there is no 28VDC:
*** - Do a check of the wiring ASM 212603 between:
*** . The AEVC (10HQ) pin AA/8A and the blower fan control-contactor (8HQ) pin Z
*** . The blower fan control-contactor (8HQ) pin X and the blower fan (20HQ) pin A/D.

**** If the wiring is not correct:
**** - Repair the related wiring.

**** If the wiring is correct:
**** - Replace CNTOR-BLOWER FAN CTL, AVNCS VENT (8HQ).

**** If the fault continues:
**** - Replace FAN-BLOWER, AVNCS VENT [20HQ] AMM 21-26-51-000-001 and AMM 21-26-51-400-001.
         b If the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ) is open:
     (b) If there is 115VAC:
   (7) If the fault continues:
     (a) If the fault continues:
Subtask 21-26-00-710-091-A
B. Do the operational test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:24:37 UTC
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