Functional Test of the Flush Control Unit (FCU)

TASK 38-31-00-720-001-A
Functional Test of the Flush Control Unit (FCU)

NOTE: The functional test of the FCU in one lavatory is given, the procedure is the same for all the other lavatories.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
14400-980	1	FCU TESTER IIA

B. Referenced Information

REFERENCE	DESIGNATION
TASK 12-15-38-613-001-A	Fill the Potable Water Tank System (Aircraft Electrical Power Available)
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
TASK 25-45-22-000-001-A	Removal of the Toilet Shroud and the Seat
TASK 25-45-22-000-802-A	Removal of the Toilet Shroud of the Space Flex Lavatory
TASK 25-45-22-400-001-A	Installation of the Toilet Shroud and the Seat
TASK 25-45-22-400-802-A	Installation of the Toilet Shroud of the Space Flex Lavatory
TASK 38-31-00-680-001-A	Draining of the Toilet System

3. Job Set-up
Subtask 38-31-00-861-065-A

A. Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).

Subtask 38-31-00-010-068-A

B. Get Access
(1) Get access to the cabin.
(2) Open the lavatory door.
(3) Remove the toilet shroud (Ref. AMM TASK 25-45-22-000-001) (Ref. AMM TASK 25-45-22-000-802).

Subtask 38-31-00-865-121-A

C. Open, safety and tag this(these) circuit breaker(s):

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 38-31-00-860-053-A

D. Preparation for Test
(1) Disconnect the electrical connector 50MG-A, 50MG1-A, 50MG2-A 50MG3-A or 50MG4-A from the Flush Control Unit (FCU).
(2) Put the 14400-980 FCU TESTER IIA in position at the FCU. (1)
(3) Connect the electrical connector 50MG-A, 50MG1-A, 50MG2-A 50MG3-A or 50MG4-A to the FCU tester IIA.
(4) Connect the electrical connector of the FCU tester IIA to the FCU.
(5) Make sure that the potable water system has enough water to do this test. If necessary fill the system (Ref. AMM TASK 12-15-38-613-001).
(6) Make sure that the waste holding tank is clean and empty. Drain if necessary (Ref. AMM TASK 38-31-00-680-001).

Subtask 38-31-00-865-122-A

E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

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 38-31-00-861-058-A

F. Make sure that the ground service network is energized (Ref. AMM TASK 24-42-00-861-001).

4. Procedure
Subtask 38-31-00-720-050-A ** ON A/C NOT FOR ALL

A. Do this Test.

ACTION	RESULT
1.On the FCU tester IIA: put the power switch to the POWER position.	On the FCU tester IIA: the green light INPUT POWER comes on. the NO FAULT light comes on and stays on. NOTE: If the NO FAULT light goes off after a few seconds (then there is a fault in the system) and one of the subsequent lights will come on: the open position limit switch, the close position limit switch, the rinse water solenoid, the FCU internal faults, the flush valve motor, the no power to FCU or disabled.
2.On the FCU tester IIA: push the flush pushbutton.	On the FCU tester IIA: the FLUSH CYCLE light comes ON.
	In the vacuum system: the vacuum blower operates for 15 s. the toilet flush cycle functions and the toilet flushes.
3.On the FCU tester: turn the blower switch to the BLOWER OFF position. push and hold the flush pushbutton.	In the vacuum system: the vacuum blower does not operate. the flush valve operates and 0.2 l (0.05 USgal) of water flows into the toilet bowl. NOTE: At the end of each flush cycle the status of the toilet is updated. The NO FAULT light will stay on if no faults are found during this cycle.
4.On the FCU tester IIA: release the blower switch to the NORMAL position.
5.On the FCU tester IIA: put the ENABLE/DISABLE switch to the DISABLE position.	On the FCU tester IIA: the NO FAULT light goes off. the NO POWER to FCU or DISABLE light is on. NOTE: If necessary you can cancel a flush cycle when you push the RESET pushbutton. NOTE: During the complete test: the SYSTEM INOP light on the Forward Attendant Panel (FAP) is on. the Vacuum System Controller (VSC) receives no data that the FCU is powered, this is normal and should be ignored, the VSC has no effect on the toilet operation, but will still control the vacuum blower. the faults shown are not stored in the VSC Electrically Erasable Programmable Read Only Memory (EEPROM). NOTE: The FCU tester IIA is defective if: two or more red lights are ON, the NO FAULT light and also one of the red lights are ON.

Subtask 38-31-00-720-050-C ** ON A/C NOT FOR ALL

A. Do this Test.

ACTION	RESULT
1.On the FCU tester IIA: put the power switch to the POWER position.	On the FCU tester IIA: the green light INPUT POWER comes on. the NO FAULT light comes on and stays on. NOTE: If the NO FAULT light goes off after a few seconds (then there is a fault in the system) and one of the subsequent lights will come on: the open position limit switch, the close position limit switch, the rinse water solenoid, the FCU internal faults, the flush valve motor, the no power to FCU or disabled.
2.On the FCU tester IIA: push the flush pushbutton.	On the FCU tester IIA: the FLUSH CYCLE light comes ON.
	In the vacuum system: the vacuum blower operates for 15 s. the toilet flush cycle functions and the toilet flushes.
3.On the FCU tester: turn the blower switch to the BLOWER OFF position. push and hold the flush pushbutton.	In the vacuum system: the vacuum blower does not operate. the flush valve operates and 0.2 l (0.05 USgal) of water flows into the toilet bowl. NOTE: At the end of each flush cycle the status of the toilet is updated. The NO FAULT light will stay on if no faults are found during this cycle.
4.On the FCU tester IIA: release the blower switch to the NORMAL position.
5.On the FCU tester IIA: put the ENABLE/DISABLE switch to the DISABLE position.	On the FCU tester IIA: the NO FAULT light goes off. the NO POWER to FCU or DISABLE light is on. NOTE: If necessary you can cancel a flush cycle when you push the RESET pushbutton. NOTE: During the complete test: the VACUUM SYSTEM DISABLED message on the WATER/WASTE page on the Flight Attendant Panel (FAP) is shown. the DUE B receives no data that the FCU is powered, this is normal and should be ignored, NOTE: The FCU tester IIA is defective if: two or more red lights are ON, the NO FAULT light and also one of the red lights are ON.

5. Close-up
Subtask 38-31-00-410-067-A

A. Close Access
(1) Disconnect the electrical connector 50MG-A, 50MG1-A, 50MG2-A 50MG3-A or 50MG4-A from the FCU tester IIA.
(2) Disconnect the electrical connector of the FCU tester IIA from the FCU.
(3) Remove the FCU tester IIA.
(4) Connect the electrical connector 50MG-A, 50MG1-A, 50MG2-A 50MG3-A or 50MG4-A to the FCU.
(5) Make sure that the work area is clean and clear of tools and other items.
(6) Install the toilet shroud (Ref. AMM TASK 25-45-22-400-001) (Ref. AMM TASK 25-45-22-400-802).
(7) Close the lavatory door.

Subtask 38-31-00-862-058-A

B. De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).

[Rev.10 from 2021] 2026.04.01 01:19:47 UTC