Removal of the Oxygen Distribution Manifold

TASK 35-12-81-000-801-A
Removal of the Oxygen Distribution Manifold

WARNING: KEEP ALL HYDROCARBONS (FUELS, LUBRICANTS, ETC.) AWAY FROM ALL SOURCE OF OXYGEN. OXYGEN BECOMES EXPLOSIVE WHEN IT TOUCHES HYDROCARBONS.

WARNING: CLEAN THE TOOLS AND MAKE SURE YOUR HANDS ARE CLEAN TO PREVENT CONTAMINATION OF THE OXYGEN SYSTEM.

CAUTION: BE VERY CAREFUL WHEN YOU DO WORK ON OR NEAR THE AIR-CONDITIONING DUCTS. THE DUCTS ARE MADE OF THIN MATERIAL AND YOU CAN EASILY BREAK THEM.

ZONE: 125
FIN: 5753HM ** ON A/C NOT FOR ALL
FIN: 5753HM1 ** ON A/C NOT FOR ALL
FIN: 5753HM2 ** ON A/C NOT FOR ALL

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 3M (10 FT)- ADJUSTABLE
No specific	AR	BAG - VINYL
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)
FOR [5753HM1] (MANIFOLD DISTRIBUTION)
No specific	AR	BAG - VINYL
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN
FOR [5753HM2] (MANIFOLD DISTRIBUTION)
No specific	AR	BAG - VINYL
No specific	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
125	LATERAL AVIONIC COMPARTMENT
812

C. Referenced Information

REFERENCE	DESIGNATION
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 35-00-00-860-001-A	Special Precautions When Working on a Gaseous Oxygen System
TASK 35-13-14-000-001-A	Removal of the Low-Pressure Oxygen Pressure-Switch
TASK 52-41-00-010-002-A	Open the Avionics Compartment Doors for Access
Oxygen Distribution Manifold ** ON A/C NOT FOR ALL
Oxygen Distribution Manifold ** ON A/C NOT FOR ALL
FOR [5753HM1] (MANIFOLD DISTRIBUTION)
TASK 35-13-14-000-802-A	Removal of the Low-Pressure Oxygen Pressure-Switches
FOR [5753HM2] (MANIFOLD DISTRIBUTION)
TASK 35-13-14-000-802-A	Removal of the Low-Pressure Oxygen Pressure-Switches

3. Job Set-up
Subtask 35-12-81-941-050-A

A. Safety Precautions

WARNING: WHEN YOU DO WORK ON THE GASEOUS OXYGEN SYSTEM, MAKE SURE THAT YOU OBEY ALL THE APPLICABLE SAFETY PRECAUTIONS. IF YOU DO NOT OBEY THESE PRECAUTIONS, INJURY TO PERSONS AND/OR DAMAGE TO THE AIRCRAFT CAN OCCUR.

(1) Obey the special precautions when you do work on the gaseous oxygen system (Ref. AMM TASK 35-00-00-860-001).
(2) Make sure that there is good airflow in the work area.

Subtask 35-12-81-861-050-A

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

Subtask 35-12-81-010-050-A

C. Get Access
(1) Put an ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position at access door 812.
(2) Open access door 812 (Ref. AMM TASK 52-41-00-010-002).

Subtask 35-12-81-860-052-A ** ON A/C NOT FOR ALL

D. Aircraft Maintenance Configuration
(1) Fully close the manual shutoff valve of the crew oxygen-storage cylinder (5750HM).
(2) Put the WARNING NOTICE(S) in position to tell persons not to open the manual shutoff valve of the crew oxygen-storage cylinder (5750HM).

Subtask 35-12-81-870-050-A ** ON A/C NOT FOR ALL

E. Bleeding of the Oxygen System
(1) In the cockpit, on the overhead panel, on the OXYGEN section of panel 21VU:
(a) Push the CREW SUPPLY pushbutton switch (the OFF legend goes off).
(2) On one of the oxygen-mask stowage box, push and hold the PRESS TO TEST AND RESET control button. At the same time, push and hold the PRESS TO TEST/EMERGENCY knob on the mask regulator:
(a) Keep the PRESS TO TEST AND RESET control button and the PRESS TO TEST/EMERGENCY knob pushed for a minimum of three seconds.

NOTE: During this time, the flow rate indicator changes from yellow to black and the volume of the sound of the oxygen flow decreases.

(b) When the flow rate indicator is black and when you no longer hear the sound of the oxygen flow:

Release the PRESS TO TEST/EMERGENCY knob.
Release the PRESS TO TEST AND RESET control button.

WARNING: MAKE SURE THAT THE PRESS TO TEST/EMERGENCY KNOB IS NOT IN THE EMERGENCY POSITION. IF IT IS IN THE EMERGENCY POSITION, THERE CAN BE A LEAK OF OXYGEN.

(c) Make sure that the PRESS TO TEST/EMERGENCY knob is not in the EMERGENCY position.
(3) Do this bleeding procedure for all the oxygen-mask stowage boxes.
(4) In the cockpit, on the overhead panel, on the OXYGEN section of panel 21VU:
(a) Release the CREW SUPPLY pushbutton switch (the OFF legend comes on).
(b) Put a WARNING NOTICE(S) in position to tell persons not to push the CREW SUPPLY pushbutton switch.

Subtask 35-12-81-860-052-B ** ON A/C NOT FOR ALL

F. Aircraft Maintenance Configuration
(1) Fully close the manual shutoff valves of the crew oxygen-storage cylinders (5750HM1 and 5750HM2).
(2) Put the WARNING NOTICE(S) in position to tell persons not to open the manual shutoff valves of the crew oxygen-storage cylinders (5750HM1 and 5750HM2).

Subtask 35-12-81-870-050-B ** ON A/C NOT FOR ALL

G. Bleeding of the Oxygen System(s)
(1) In the cockpit, on the overhead panel, on the OXYGEN section of panel 21VU:
(a) Push the CREW SUPPLY pushbutton switch (the OFF legend goes off).
(2) FOR [5753HM1] (MANIFOLD DISTRIBUTION)
(a) On the captain oxygen-mask stowage-box, push and hold the PRESS TO TEST AND RESET control button. At the same time, push and hold the PRESS TO TEST/EMERGENCY knob on the mask regulator:
1 Keep the PRESS TO TEST AND RESET control button and the PRESS TO TEST/EMERGENCY knob pushed for a minimum of three seconds.

NOTE: During this time, the flow rate indicator changes from yellow to black and the volume of the sound of the oxygen flow decreases.

2 When the flow rate indicator is black and when you no longer hear the sound of the oxygen flow:

Release the PRESS TO TEST/EMERGENCY knob.
Release the PRESS TO TEST AND RESET control button.

WARNING: MAKE SURE THAT THE PRESS TO TEST/EMERGENCY KNOB IS NOT IN THE EMERGENCY POSITION. IF IT IS IN THE EMERGENCY POSITION, THERE CAN BE A LEAK OF OXYGEN.

3 Make sure that the PRESS TO TEST/EMERGENCY knob is not in the EMERGENCY position.
(3) FOR [5753HM2] (MANIFOLD DISTRIBUTION)
(a) On the first-officer oxygen-mask stowage-box, push and hold the PRESS TO TEST AND RESET control button. At the same time, push and hold the PRESS TO TEST/EMERGENCY knob on the mask regulator:
1 Keep the PRESS TO TEST AND RESET control button and the PRESS TO TEST/EMERGENCY knob pushed for a minimum of three seconds.

NOTE: During this time, the flow rate indicator changes from yellow to black and the volume of the sound of the oxygen flow decreases.

2 When the flow rate indicator is black and when you no longer hear the sound of the oxygen flow:

Release the PRESS TO TEST/EMERGENCY knob.
Release the PRESS TO TEST AND RESET control button.

WARNING: MAKE SURE THAT THE PRESS TO TEST/EMERGENCY KNOB IS NOT IN THE EMERGENCY POSITION. IF IT IS IN THE EMERGENCY POSITION, THERE CAN BE A LEAK OF OXYGEN.

3 Make sure that the PRESS TO TEST/EMERGENCY knob is not in the EMERGENCY position.
(4) Do this bleeding procedure for all the oxygen-mask stowage boxes.
(5) In the cockpit, on the overhead panel, on the OXYGEN section of panel 21VU:
(a) Release the CREW SUPPLY pushbutton switch (the OFF legend comes on).
(b) Put a WARNING NOTICE(S) in position to tell persons not to push the CREW SUPPLY pushbutton switch.

Subtask 35-12-81-865-052-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	OXYGEN/CREW/OXY/SPLY	1HT	HA01

4. Procedure

CAUTION: PUT DRY AND CLEAN METAL OR PLASTIC PLUGS ON ALL PIPES OR UNITS THAT YOU REMOVE TEMPORARILY. THEN PUT EACH PIPE OR UNIT IN A SEALED VINYL BAG. IF YOU DO NOT OBEY THESE INSTRUCTIONS, CONTAMINATION OF THE OXYGEN SYSTEM CAN OCCUR.

Subtask 35-12-81-000-050-A ** ON A/C NOT FOR ALL

A. Removal of the Oxygen Distribution Manifold
(1) Disconnect the electrical connector (10):

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

(a) Disconnect the electrical connector (10) from the LP oxygen pressure-switch (11).
(b) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(2) If installed, remove the OXYGEN CLEAN sticker from the oxygen inlet port (5), the oxygen outlet port (7) and the LP oxygen pressure-switch (11).

NOTE: It is not necessary to install a new OXYGEN CLEAN stickers.

(3) Disconnect the coupling nuts (6) and (8).
(4) Disconnect the oxygen inlet port (5) and the oxygen outlet port (7) from the oxygen distribution manifold (1).
(5) Remove and discard the rings (9).
(6) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN and a BAG - VINYL on the disconnected line ends.
(7) Hold the oxygen distribution manifold (1) and remove the bolts (2) and the washers (3).
(8) Remove the oxygen distribution manifold (1) from its support (4).
(9) If necessary, remove the LP oxygen pressure-switch (11) from the oxygen distribution manifold (1) (Ref. AMM TASK 35-13-14-000-001).
(10) Put the oxygen distribution manifold (1) in a BAG - VINYL.

Subtask 35-12-81-000-050-B ** ON A/C NOT FOR ALL

A. Removal of Oxygen Distribution Manifold
(1) FOR [5753HM1] (MANIFOLD DISTRIBUTION)
(a) Disconnect the electrical connector (2):

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

1 Disconnect the electrical connector (2) from the LP oxygen pressure-switch (3).
2 Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(b) If installed, remove the OXYGEN CLEAN sticker from the oxygen inlet port (8), the oxygen outlet ports (11) and the LP oxygen pressure-switch (3).

NOTE: It is not necessary to install a new OXYGEN CLEAN stickers.

(c) Disconnect the coupling nuts (7) and (10).
(d) Disconnect the oxygen inlet port (8) and the oxygen outlet ports (11) from the oxygen distribution manifold (4).
(e) Remove and discard the rings (9).
(f) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN and a BAG - VINYL on the disconnected line ends.
(g) Hold the oxygen distribution manifold (4) and remove the bolts (5) and the washers (6).
(h) Remove the oxygen distribution manifold (4) from its support (1).
(i) If necessary, remove the LP oxygen pressure-switch (3) from the oxygen distribution manifold (4) (Ref. AMM TASK 35-13-14-000-802).
(j) Put the oxygen distribution manifold (4) in a BAG - VINYL.
(2) FOR [5753HM2] (MANIFOLD DISTRIBUTION)
(a) Disconnect the electrical connector (2):

CAUTION: MAKE SURE THAT THE ELECTRICAL CONNECTORS ARE CLEAN BEFORE YOU DISCONNECT OR CONNECT THEM. CONTAMINATION ON THE ELECTRICAL CONNECTORS CAN CAUSE DAMAGE TO EQUIPMENT.

NOTE: It is not necessary to install a new OXYGEN CLEAN stickers.

(c) Disconnect the coupling nuts (7) and (10).
(d) Disconnect the oxygen inlet port (8) and the oxygen outlet ports (11) from the oxygen distribution manifold (4).
(e) Remove and discard the rings (9).
(f) Put a PLUG - BLANKING, APPROVED FOR USE WITH OXYGEN and a BAG - VINYL on the disconnected line ends.
(g) Hold the oxygen distribution manifold (4) and remove the bolts (5) and the washers (6).
(h) Remove the oxygen distribution manifold (4) from its support (12).
(i) If necessary, remove the LP oxygen pressure-switch (3) from the oxygen distribution manifold (4) (Ref. AMM TASK 35-13-14-000-802).
(j) Put the oxygen distribution manifold (4) in a BAG - VINYL.

[Rev.10 from 2021] 2026.04.01 01:04:20 UTC