Draining of the Potable Water System (with Electrical Power)

TASK 12-24-38-680-001-A
Draining of the Potable Water System (with Electrical Power)

1. Reason for the Job
Self Explanatory
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	HOSE - DRAIN

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
133AL, 171AL
192NB

D. Referenced Information

REFERENCE	DESIGNATION
TASK 12-31-38-660-001-A	Cold Weather Maintenance - Water/Waste
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
Potable Water Service-Panel ** ON A/C NOT FOR ALL
Potable Water Service-Panel ** ON A/C NOT FOR ALL
Potable Water Service-Panel ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 12-24-38-680-050-A ** ON A/C NOT FOR ALL

A. Draining of the Potable water System

CAUTION: MAKE SURE THAT THE DRAIN VALVES STAY IN THE DRAIN POSITION AFTER YOU DRAIN THE POTABLE WATER SYSTEM IF:

THE BLEED AIR SYSTEM IS OFF, AND
THE OUTSIDE AIR TEMPERATURE IS BELOW 0 DEG.C (32 DEG.F).

THIS WILL PREVENT DAMAGE TO THE POTABLE WATER SYSTEM.

(1) You must drain the water system when the outside air temperature is as shown in the cold weather maintenance - procedure (Ref. AMM TASK 12-31-38-660-001).

Subtask 12-24-38-680-050-B ** ON A/C NOT FOR ALL

A. Draining of the Potable water System

CAUTION: MAKE SURE THAT THE DRAIN VALVES STAY IN THE DRAIN POSITION AFTER YOU DRAIN THE POTABLE WATER SYSTEM IF:

THE BLEED AIR SYSTEM IS OFF, AND
THE OUTSIDE AIR TEMPERATURE IS BELOW 0 DEG.C (32 DEG.F).

THIS WILL PREVENT DAMAGE TO THE POTABLE WATER SYSTEM.

(1) You must drain the water system when the outside air temperature is as shown in the cold weather maintenance - procedure (Ref. AMM TASK 12-31-38-660-001).

Subtask 12-24-38-861-051-A

B. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 12-24-38-865-052-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
2000VU	WATER SYSTEM-QANT-IND	1MA	B01
** ON A/C NOT FOR ALL
2001VU	WATER SYS-QUANT-IND	1MA	B06
** ON A/C NOT FOR ALL
2001VU	WATER SYS-DRAIN	1MP	B05
** ON A/C NOT FOR ALL
2001VU	WATER-SYS-DRAIN	1MP	B05

Subtask 12-24-38-941-052-A ** ON A/C NOT FOR ALL

D. Put the ACCESS PLATFORM 2M (6 FT) in position below the 133AL and 171AL.

Subtask 12-24-38-941-052-B ** ON A/C NOT FOR ALL

D. Put the ACCESS PLATFORM 2M (6 FT) in position below the 133AL, 192NB and 171AL.

Subtask 12-24-38-860-050-A ** ON A/C NOT FOR ALL

E. Aircraft Maintenance Configuration
(1) Make sure that the potable water shutoff-valve in each lavatory is open.
(2) Make sure that the potable water shutoff-valve in each wet galley is open.
(3) Make sure that the potable water-mixing timer control-knob in each lavatory is set to the center position (between the RED and BLUE band).
(4) Make sure that the potable water shutoff-valve in each galley is open.

Subtask 12-24-38-860-050-B ** ON A/C NOT FOR ALL

Subtask 12-24-38-010-054-A ** ON A/C NOT FOR ALL

F. Open for Access
(1) Open the access panels 133AL 171AL.
(2) Remove the cap from the fill and drain port on the service panel 2023VU.

Subtask 12-24-38-010-054-B ** ON A/C NOT FOR ALL

F. Open for Access
(1) Open the access panels 133AL 192NB 171AL.
(2) Remove the cap from the fill and drain port on the service panel 2023VU.

4. Procedure
Subtask 12-24-38-680-051-B ** ON A/C NOT FOR ALL

A. Draining of the Potable Water System (PWS)

Potable Water Service-Panel ** ON A/C NOT FOR ALL

CAUTION: MAKE SURE THAT THE DRAIN VALVES ARE IN THE CLOSED POSITION IF THE BLEED AIR SYSTEM IS "ON". YOU MUST DO THIS LESS THAN 10 MIN AFTER THE FLOW OF WATER FROM THE DRAIN PORTS OF THE POTABLE WATER SYSTEM STOPS. THIS WILL PREVENT DAMAGE TO THE POTABLE WATER SYSTEM.

(1) Connect the HOSE - DRAIN to:

The fill and drain port on Potable Water Service Panel (PWSP) 2023VU
The drain port on the forward drain panel.

(2) On PWSP 2023VU:
(a) Turn fill and drain control handle 3254MM to the PULL TO DRAIN position. Then, pull it to the mechanical stop.

NOTE: Drain-valve control light 2MP comes on.

NOTE: The water drains from:

The fill and drain port on PWSP 2023VU
The drain port on the forward drain panel.

(3) In the lavatories, push the toilet flush button to drain the remaining water from the toilet system.
(4) Operate the water faucet(s), the coffee makers and the water heater in the galley(s) (if installed) to drain them.
(5) Do step (4) again and again until the remaining water is fully drained from the galley(s).

NOTE: After you drain the PWS:

15 minutes is necessary to drain the water from the galley(s).
The position of the aircraft has an effect on the time necessary to drain the water from the galley(s).

(6) You must do step (4) again if the aircraft is moved.
(7) When the system is drained, remove the drain hose from:

The fill and drain port on PWSP 2023VU
The drain port on the forward panel.

(8) Put fill and drain control handle 3254MM back to the NORMAL position.

NOTE: If you drain the PWS in cold weather, it is recommended that you put the fill and drain control handle in the DRAIN position.

Subtask 12-24-38-680-051-C ** ON A/C NOT FOR ALL

A. Draining of the Potable Water System (PWS)

Potable Water Service-Panel ** ON A/C NOT FOR ALL

(1) Connect the HOSE - DRAIN to:

The fill and drain port on Potable Water Service Panel (PWSP) 2023VU
The drain port on the mid drain and overflow panel
The drain port on the forward drain panel.

(2) On PWSP 2023VU:
(a) Turn fill and drain control handle 3254MM to the PULL TO DRAIN position. Then, pull it to the mechanical stop.

NOTE: The lights that follow come on:

Drain-valve control light 2MP
Drain-valve control light 12MP
Overflow-valve control light 6MP.

NOTE: The water drains from:

The fill and drain port on PWSP 2023VU
The drain port on the mid drain and overflow panel
The drain port on the forward drain panel.

NOTE: After you drain the PWS:

15 minutes is necessary to drain the water from the galley(s).
The position of the aircraft has an effect on the time necessary to drain the water from the galley(s).

(6) You must do step (4) again if the aircraft is moved.
(7) When the system is drained, remove the drain hose from:

The fill and drain port on PWSP 2023VU
The drain port on the mid drain and overflow panel
The drain port on the forward drain panel.

(8) Put fill and drain control handle 3254MM back to the NORMAL position.

NOTE: If you drain the PWS in cold weather, it is recommended that you put the fill and drain control handle in the DRAIN position.

5. Close-up
Subtask 12-24-38-410-052-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Clean and dry the panels with a lint free cloth Textile-Lint free Cotton - (Material No.14SBA1) .
(3) Install the cap on the fill and drain port of the service panel.

NOTE: If the draining is done in cold weather the caps and access panels should be left open (Ref. AMM TASK 12-31-38-660-001).

(4) Close the access panels 133AL 171AL.

Subtask 12-24-38-410-052-B ** ON A/C NOT FOR ALL

NOTE: If the draining is done in cold weather the caps and access panels should be left open (Ref. AMM TASK 12-31-38-660-001).

(4) Close the access panels 133AL 192NB 171AL.

Subtask 12-24-38-862-051-A

B. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

Subtask 12-24-38-942-055-A

C. Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.04.01 03:56:43 UTC