W DOC AIRBUS | TSM A320F

No Oxygen to the Crew Oxygen Masks with REGUL LO PR Indication

TASK 35-10-00-810-822-A
No Oxygen to the Crew Oxygen Masks with REGUL LO PR Indication

1. Possible Causes
  • SOL VALVE-LP OXY SPLY [3HT]
  • P/BSW-OXYGEN/CREW SUPPLY (2HT)
  • wiring from the LP oxygen supply solenoid valve (3HT) pin A/B to the ground terminal
  • wiring from the LP oxygen supply solenoid valve (3HT) to the pushbutton switch (2HT)
  • LP SOLENOID SUPPLY VALVE [3HT1]
  • LP SOLENOID SUPPLY VALVE [3HT2]
  • wiring
  • XMTR/PRESS REG-OXY [4HT]
  • PRESS.TRANSM.REGULATO [4HT2]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 35-12-41-710-001
Operational Test of the Full Face/Quick Donning Oxygen Masks
ASM 351301
AMM 35-13-15-000-802
Removal of the Oxygen Pressure Regulator/Transmitters
AMM 35-13-15-400-802
Installation of the Oxygen Pressure Regulator/Transmitters
AMM 35-13-51-000-001
Removal of the Low-Pressure Oxygen-Supply Solenoid-Valve
AMM 35-13-51-000-802
Removal of the Low-Pressure Oxygen-Supply Solenoid-Valves
AMM 35-13-51-400-001
Installation of the Low-Pressure Oxygen-Supply Solenoid-Valve
AMM 35-13-51-400-802
Installation of the Low-Pressure Oxygen-Supply Solenoid-Valves
3. Fault Confirmation
Subtask 35-10-00-710-073-A
A. Test
   (1) Do the operational test of the full-face/quick-donning oxygen masks AMM 35-12-41-710-001.
4. Fault Isolation
Subtask 35-10-00-810-072-A ** ON A/C NOT FOR ALL
A. If during the operational test there is no oxygen at each mask with REGUL LO PR indication:
  • make sure that there is 28VDC on the LP oxygen supply solenoid valve (3HT) pin A/A.
   (1) If there is 28VDC:
   (2) If there is no 28VDC:
  • replace the P/BSW-OXYGEN/CREW SUPPLY (2HT) ASM 351301.
   (3) If the fault continues:
  • do a check for a ground signal at the pin A/B of the LP oxygen supply solenoid valve (3HT) ASM 351301.
     (a) If there is no ground signal:
  • repair the wiring from the LP oxygen supply solenoid valve (3HT) pin A/B to the ground terminal ASM 351301.
     (b) If there is a ground signal:
  • do a check and repair the wiring from the LP oxygen supply solenoid valve (3HT) to the pushbutton switch (2HT) pin A/A ASM 351301.
Subtask 35-10-00-710-074-A ** ON A/C NOT FOR ALL
B. Test
   (1) Do the test given in Para. 3.A.
Subtask 35-10-00-810-072-B ** ON A/C NOT FOR ALL
C. During the operational test, if there is:
   (1) No oxygen flow at each oxygen mask and the REGUL 1+2 LO PR indication comes into view:
  • Make sure that there is 28VDC at the LP oxygen-supply solenoid-valves (3HT1) and (3HT2), pins A/A.
     (a) If there is 28VDC:
     (b) If there is no 28VDC:
  • Replace the P/BSW-OXYGEN/CREW SUPPLY (2HT), ASM 351301.
     (c) If the fault continues:
  • Do a check for a ground signal at pins A/B of the LP oxygen-supply solenoid-valves (3HT1) and (3HT2), ASM 351301.
       1 If there is no ground signal:
  • Repair the wiring from the LP oxygen-supply solenoid-valve (3HT1) pin A/B to the ground terminal, ASM 351301.
  • Repair the wiring from the LP oxygen-supply solenoid-valve (3HT2) pin A/B to the ground terminal, ASM 351301.
       2 If there is a ground signal:
  • Do a check and repair the wiring from the LP oxygen-supply solenoid-valve (3HT1) pin A/A to the pushbutton switch (2HT) pin A/B1, ASM 351301.
  • Do a check and repair the wiring from the LP oxygen-supply solenoid-valve (3HT2) pin A/A to the pushbutton switch (2HT) pin A/D1, ASM 351301.
     (d) If the fault continues:
   (2) No oxygen flow at the Captain and Third Occupant oxygen-masks and the REGUL 1 LO PR indication comes into view:
  • Make sure that there is 28VDC at the LP oxygen-supply solenoid-valve (3HT1), pin A/A.
     (a) If there is 28VDC:
     (b) If there is no 28VDC:
  • Replace the P/BSW-OXYGEN/CREW SUPPLY (2HT), ASM 351301.
     (c) If the fault continues:
  • Do a check for a ground signal at pin A/B of the LP oxygen-supply solenoid-valve (3HT1), ASM 351301.
       1 If there is no ground signal:
  • Repair the wiring from the LP oxygen-supply solenoid-valve (3HT1) pin A/B to the ground terminal, ASM 351301.
       2 If there is a ground signal:
  • Do a check and repair the wiring from the LP oxygen-supply solenoid-valve (3HT1) pin A/A to the pushbutton switch (2HT) pin A/B1, ASM 351301.
     (d) If the fault continues:
   (3) No oxygen flow at the First Officer and Fourth Occupant oxygen-masks and the REGUL 2 LO PR indication comes into view:
  • Make sure that there is 28VDC at the LP oxygen-supply solenoid-valve (3HT2), pin A/A.
     (a) If there is 28VDC:
     (b) If there is no 28VDC:
  • Replace the P/BSW-OXYGEN/CREW SUPPLY (2HT), ASM 351301.
     (c) If the fault continues:
  • Do a check for a ground signal at pin A/B of the LP oxygen-supply solenoid-valve (3HT2), ASM 351301.
       1 If there is no ground signal:
  • Repair the wiring from the LP oxygen-supply solenoid-valve (3HT2) pin A/B to the ground terminal, ASM 351301.
       2 If there is a ground signal:
  • Do a check and repair the wiring from the LP oxygen-supply solenoid-valve (3HT2) pin A/A to the pushbutton switch (2HT) pin A/D1, ASM 351301.
     (d) If the fault continues:
Subtask 35-10-00-710-074-B ** ON A/C NOT FOR ALL
D. Test
   (1) Do the test given in Para. 3.A.
   (2) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU:
  • Push the CREW SUPPLY pushbutton switch (the OFF legend goes off).
   (3) On the lower ECAM DU, make sure that you cannot see indications that follow:
  • REGUL 1 LO PR
  • REGUL 2 LO PR
  • REGUL 1+2 LO PR.
   (4) In the cockpit, on the OXYGEN section of the overhead control and indicating panel 21VU:
  • Release the CREW SUPPLY pushbutton switch (the OFF legend comes on).
[Rev.8 from Aug 2018] 2026.04.04 04:33:38 UTC
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