LAV X Failure

TASK 38-31-00-810-827-A
LAV X Failure

1. Possible Causes

FCU
wiring
WATER VALVE
FLUSH VALVE

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 38-30-00-615-002	Blockage Removal (Orbital Flush Valve)
AMM 38-31-00-710-009	Operational Test of the Toilet Unit
AMM 38-31-00-740-001	BITE Test of the Vacuum Toilet System
ASM 383111
AMM 38-31-12-000-001	Removal of the Flush Control Unit
AMM 38-31-12-400-001	Installation of the Flush Control Unit
AMM 38-31-55-000-001	Removal of the Water Valve
AMM 38-31-55-400-001	Installation of the Water Valve
AMM 38-31-57-000-001	Removal of the Flush Valve
AMM 38-31-57-400-001	Installation of the Flush Valve
MCDU Display

3. Fault Confirmation
Subtask 38-31-00-710-100-A ** ON A/C NOT FOR ALL

A. Do a test of the vacuum toilet system AMM 38-31-00-710-009.

Subtask 38-31-00-740-067-A ** ON A/C NOT FOR ALL

B. Do the bite test AMM 38-31-00-740-001.

4. Fault Isolation
Subtask 38-31-00-810-119-C ** ON A/C NOT FOR ALL

A. If the operational test does not operate:

Refer to the bite test last leg or previous leg report.
MCDU Display ** ON A/C NOT FOR ALL

(1) If the LAST LEG or PREVIOUS LEG REPORT give the maintenance message LAV X FCU:

replace the FCU AMM 38-31-12-000-001 and AMM 38-31-12-400-001.
If the fault continues:
do a check and repair the wiring between the:
- FCU connector J2/B / J2/A / J2/C and flush valve motor ASM 383111.

Subtask 38-31-00-810-120-A ** ON A/C NOT FOR ALL

B. If the operational test does not operate:

Refer to the bite test last leg or previous leg report page.
MCDU Display ** ON A/C NOT FOR ALL

(1) If the LAST LEG or PREVIOUS LEG REPORT give the maintenance message LAV X WATER VALVE:

replace the WATER VALVE , AMM 38-31-55-000-001 and AMM 38-31-55-400-001.

Subtask 38-31-00-810-122-A ** ON A/C NOT FOR ALL

C. If the operational test does not operate:

Refer to the bite test last leg or previous leg report.
MCDU Display ** ON A/C NOT FOR ALL

(1) If the LAST LEG REPORT or PREVIOUS LEG REPORT gives the maintenance message LAV X FLUSH VALVE MOTOR:

make sure that the flush valve is not blocked.
if blocked, remove the blockage AMM 38-30-00-615-002.

(2) If the fault continues:

replace the FLUSH VALVE , AMM 38-31-57-000-001 and AMM 38-31-57-400-001.

Subtask 38-31-00-810-123-A ** ON A/C NOT FOR ALL

D. If the operational test does not operate:

Refer to the bite test last leg or previous leg report page.
MCDU Display ** ON A/C NOT FOR ALL

(1) If the LAST LEG REPORT or PREVIOUS LEG REPORT gives the maintenance message LAV X FLUSH VALVE CLOSED LIMIT SWITCH: or
LAV X FLUSH VALVE OPEN LIMIT SWITCH:

adjust the closed or the open limit switch, refer to the manufacturer's instructions given in the related Component Maintenance Manual (CMM).

(2) If the fault continues:

replace the FLUSH VALVE , AMM 38-31-57-000-001 and AMM 38-31-57-400-001.

Subtask 38-31-00-710-101-A ** ON A/C NOT FOR ALL

E. Test
(1) Do the test as given in paragraph 3. A. to check the correct operation.
(2) After the subsequent flight, make sure that the fault does not continue.

[Rev.8 from Aug 2018] 2026.04.04 04:34:14 UTC