W DOC AIRBUS | TSM A320F

Trim-Air Pressure Regulating Valve or Pressure Switch Fault

TASK 21-63-00-810-849-A
Trim-Air Pressure Regulating Valve or Pressure Switch Fault

1. Possible Causes
  • TRIM AIR PRESS VALVE [14HK]
  • TRIM AIR PRESS SWITCH [26HK]
  • wiring
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 21-63-00-710-004
Operational Test of the Cockpit and Cabin Temperature Control with CFDS/MCDU
AMM 21-63-00-920-001
Scheduled Replace/Restore the Trim-Air Pressure-Regulating Valve Filter
ASM 216301
ASM 216303
AMM 21-63-19-000-001
Removal of the Hot Air-Pressure Switch
AMM 21-63-19-400-001
Installation of the Hot Air-Pressure Switch
AMM 21-63-52-000-001
Removal of the Pressure Regulating Valve
AMM 21-63-52-400-001
Installation of the Pressure Regulating Valve
3. Fault Confirmation
Subtask 21-63-00-710-134-A ** ON A/C NOT FOR ALL
A. Do the operational test of the cockpit and cabin temperature-control system with CFDS/MCDU AMM 21-63-00-710-004.
NOTE: If a fault is detected, the ZC gives a fault code for shop maintenance in addition to the related CFDS message(s). For detailed information see the applicable Page Block 301.
Subtask 21-63-00-710-134-B ** ON A/C NOT FOR ALL
A. Do the operational test of the cockpit and cabin temperature-control system with CFDS/MCDU AMM 21-63-00-710-004.
4. Fault Isolation
Subtask 21-63-00-810-139-A ** ON A/C NOT FOR ALL
A. If the test gives the maintenance message TRIM AIR PRESS VALVE OR PRESS SWITCH:
NOTE: Work step (1) is not applicable for TAPRV P/N 70853A010001.
   (1) replace the trim air pressure-regulating valve filter AMM 21-63-00-920-001.
   (2) If the fault continues:
   (3) If the fault continues:
   (4) If the fault continues:
  • do a check and repair the wiring ASM 216301 and ASM 216303 from:
  • the VALVE (14HK) to the ZC (8HK),
  • the VALVE (14HK) to ground,
  • the VALVE (14HK) to the CB (3HK) via the P/BSW (7HK),
  • the SWITCH (26HK) to the ZC (8HK) and,
  • the SWITCH (26HK) to ground.
Subtask 21-63-00-810-140-A ** ON A/C NOT FOR ALL
B. If the test gives the maintenance message TEST OK, but the POST FLIGHT REPORT and the PREVIOUS LEG REPORT give the maintenance message TRIM AIR PRESS VALVE OR PRESS SWITCH:
   (1) For TAPRV P/N 746A0000-XX:
     (a) replace the TRIM AIR PRESS VALVE [14HK] AMM 21-63-52-000-001 and AMM 21-63-52-400-001.
     (b) If the fault continues:
   (2) For TAPRV P/N 70853AXXXXXX:
     (a) replace the TRIM AIR PRESS SWITCH [26HK] AMM 21-63-19-000-001 and AMM 21-63-19-400-001.
     (b) If the fault continues:
Subtask 21-63-00-810-139-B ** ON A/C NOT FOR ALL
C. If the test gives the maintenance message TRIM AIR PRESS VALVE(14HK) OR PRESS SWITCH(26HK):
NOTE: Work step (1) is not applicable for TAPRV P/N 70853A010001.
   (1) replace the trim air pressure-regulating valve filter AMM 21-63-00-920-001.
   (2) If the fault continues:
   (3) If the fault continues:
   (4) If the fault continues:
  • do a check and repair the wiring ASM 216301 and ASM 216303 from:
  • the VALVE (14HK) to the ACSC1 (47HH),
  • the VALVE (14HK) to ground,
  • the VALVE (14HK) to the CB (58HH) via the P/BSW (7HK),
  • the SWITCH (26HK) to the ACSC1 (47HH) and,
  • the SWITCH (26HK) to ground.
Subtask 21-63-00-810-140-B ** ON A/C NOT FOR ALL
D. If the test gives the maintenance message TEST OK, but the POST FLIGHT REPORT and the PREVIOUS LEG REPORT give the maintenance message TRIM AIR PRESS VALVE (14HK) OR PRESS SWITCH(26HK):
   (1) For TAPRV P/N 746A0000-XX:
     (a) replace the TRIM AIR PRESS VALVE [14HK] AMM 21-63-52-000-001 and AMM 21-63-52-400-001.
     (b) If the fault continues:
   (2) For TAPRV P/N 70853AXXXXXX:
     (a) replace the TRIM AIR PRESS SWITCH [26HK] AMM 21-63-19-000-001 and AMM 21-63-19-400-001.
     (b) If the fault continues:
Subtask 21-63-00-720-052-A
E. Do the test as given in the Para. 3.A.
[Rev.8 from Aug 2018] 2026.04.04 04:25:05 UTC
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