Draining of the Potable Water System (without Electrical Power)

TASK 12-24-38-680-002-A
Draining of the Potable Water System (without 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)

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
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 12-24-38-680-052-A

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 12-24-38-941-053-A ** ON A/C NOT FOR ALL

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

Subtask 12-24-38-941-053-B ** ON A/C NOT FOR ALL

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

Subtask 12-24-38-860-051-A ** ON A/C NOT FOR ALL

C. Aircraft Maintenance Configuration
(1) Make sure that the potable water shutoff valve in each lavatory is open.
(2) 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).
(3) Make sure that the potable water shutoff valve in each galley is open.

Subtask 12-24-38-860-051-B ** ON A/C NOT FOR ALL

C. 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 galley is open.

Subtask 12-24-38-010-055-A ** ON A/C NOT FOR ALL

D. 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 12-24-38-010-055-B ** ON A/C NOT FOR ALL

D. 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 12-24-38-680-053-C ** ON A/C NOT FOR ALL

A. Drain the Potable Water System

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 drain hoses to:

the fill and drain port on the service panel
the drain port on the mid drain and overflow panel
the drain port on the forward drain panel.

(2) On the potable water service-panel 2023VU:
(a) Turn the fill and drain control handle 3254MM to the PULL TO DRAIN position. Then pull it out to the mechanical stop.
(3) On the mid drain panel:
(a) Turn the overflow control handle to the OPEN position.
(b) Turn the drain control handle to the OPEN position.
(4) On the forward drain panel:
(a) Turn the drain control handle on the drain panel to the OPEN position.

NOTE: Water will drain from:

the fill and drain port on the service panel 2023VU
the drain port on the mid drain panel
the drain port on the forward drain panel.

(5) When the system is drained:

push in and turn the fill and drain control handle 3254MM to the NORMAL position.
turn the drain control handle on the mid drain panel to the CLOSED position.
turn the overflow control handle on the mid drain panel to the CLOSED position.
turn the drain control handle on the forward drain panel to the CLOSED position.

(6) Disconnect the drain hose(s) from the drain port(s).
(7) Clean and dry the panels with a lint-free cotton cloth Textile-Lint free Cotton - (Material No.14SBA1) .
(8) Install the cap on the fill and drain port of the service panel.

Subtask 12-24-38-680-053-D ** ON A/C NOT FOR ALL

A. Drain the Potable water System

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

(1) Connect the drain hoses to:

the fill and drain port on the service panel
the drain port on the forward drain panel.

(2) On the potable water service-panel 2023VU:
(a) Turn the fill and drain control handle 3254MM to the PULL TO DRAIN position. Then pull it out to the mechanical stop.
(3) On the forward drain panel:
(a) Turn the drain control handle to the OPEN position.

NOTE: Water will drain from:

the fill and drain port on the service panel 2023VU
the drain port on the forward drain panel.

NOTE: Water will remain in the supply lines to the toilet units.

(4) When the system is drained:

push in and then turn the fill and drain control handle 3254MM to the NORMAL position.
turn the drain control handle on the forward drain panel to the CLOSED position.

(5) Disconnect the drain hose(s) from the drain port(s).
(6) Clean and dry the panels with a lint-free cotton cloth Textile-Lint free Cotton - (Material No.14SBA1) .
(7) Install the cap on the fill and drain port of the service panel.

5. Close-up
Subtask 12-24-38-410-053-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) Close the access panels 133AL, 171AL.
(3) Remove the access platform(s).
(4) Remove all the ground support equipment, the maintenance equipment, the standard and special tools and all other items.

Subtask 12-24-38-410-053-B ** 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) Close the access panels 133AL, 192NB, 171AL.
(3) Remove the access platform(s).
(4) Remove all the ground support equipment, the maintenance equipment, the standard and special tools and all other items.

[Rev.10 from 2021] 2026.04.01 03:56:44 UTC