Leak Test of the Vacuum Toilet System (VTS)

TASK 38-31-00-790-002-A
Leak Test of the Vacuum Toilet System (VTS)

1. Reason for the Job

NOTE: This task gives the instructions necessary to do a full leak test before and after the maintenance work on all the VTS components, but not the vacuum generator.

NOTE: A different short leak test is also available and is applicable only for the equipment installed in the lavatories and the galleys. If you do the short leak test, it is not necessary to do this full leak test.

NOTE: Two persons are necessary to do this procedure.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 2M (6 FT)
No specific	1	STOPWATCH
9501501-4000	1	VACUUM TOILET-LEAK TESTER

B. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TSM 38-31-00-810-854	Vacuum Pressure of the Vacuum System is Too Low
Measuring Tool
Pressure - Altitude Graph

3. Job Set-up
Subtask 38-31-00-860-056-A

A. Preparation for a Leak Check
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001)

Subtask 38-31-00-865-134-A

B. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-VACUUM-SYS	35MG	A06
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-VACUUM-GEN	33MG	A08
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-E	34MG	A04
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-D	39MG	A03
** ON A/C ALL
2001VU	VACU TOIL SYS-LAV PWR-A	32MG	A01
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-VACU-SYS	35MG	A06
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-VACU-GEN	33MG	A08
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-G	34MG	A04
2001VU	VACU TOIL SYS-LAV PWR-F	39MG	A03
2001VU	VACU TOIL SYS-LAV PWR-D	45MG	A02
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-L	45MG	A02
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-L	23MG	A05
** ON A/C NOT FOR ALL
2001VU	VACU TOIL SYS-LAV PWR-M	34MG	A04

Subtask 38-31-00-941-061-A

C. Put an ACCESS PLATFORM 2M (6 FT) in position below the vacuum-system overboard vent.

Subtask 38-31-00-480-054-A

WARNING: ALWAYS WEAR RUBBER GLOVES, GOGGLES AND PROTECTIVE CLOTHES WHEN YOU DO THIS TASK.

D. Installation of the test tool 9501501-4000 VACUUM TOILET-LEAK TESTER.

Measuring Tool

(1) Clean the component interfaces and the adjacent area.
(2) Make sure that the Leak Tester is in the correct condition and that the date of the calibration is not expired.
(3) Put the indication unit (P/N 9501501-4100) and the test plug (P/N 9501501-4400) in position in the overboard vent.
(4) Make sure that the mark on the test plug touches the forward edge of the fuselage.
(5) Make sure that you can clearly read the manometer.
(6) Tighten the serrated nut of the test plug with your hand to lock the tool in the overboard vent.
(7) Close the manual ventilation valve of the measuring tool.

4. Procedure
Subtask 38-31-00-790-052-A

A. Leak Check of the Vacuum Toilet System
(1) Do this test before the removal and after the installation of components of the vacuum toilet system and compare the recorded results.

NOTE: The result (of the test done) after the installation must not be more than 10% below the result (of the test done) before the removal.
This makes sure that the component is correctly installed and that there are no leaks.

(2) Make sure that the measured differential pressure values (result) are not less than the limits given in the Figure

Pressure - Altitude Graph

NOTE: All values shown in this test are negative pressures.

Leak Test

ACTION	RESULT
1.In each lavatory:	At the manometer:
Push and release the toilet flush switch.
Use a STOPWATCH and record the time of the flush cycle.	After 30 seconds, record the value and compare it with the calculated value from graph 1. After 120 seconds, record the value and compare it with the calculated value from graph 2.
At the measuring tool: Open the manual ventilation valve and release the pressure. Wait 2 minutes. Close the manual ventilation valve.	At the manometer: The pressure is zero.

(3) If the result of the leak test is not satisfactory, refer to the troubleshooting procedure TSM 38-31-00-810-854.

5. Close-up
Subtask 38-31-00-080-054-A

A. Removal of the Test Tool

WARNING: ALWAYS WEAR RUBBER GLOVES, GOGGLES AND PROTECTIVE CLOTHES WHEN YOU DO THIS TASK.

(1) Disconnect the indication unit and the test plug from the overboard vent.
(2) Clean the component interfaces and the adjacent area.

Subtask 38-31-00-942-062-A

B. Put the aircraft back to its initial configuration.
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove the access platform(s).
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(4) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

[Rev.10 from 2021] 2026.04.01 12:40:12 UTC