Removal of the Pressure Regulating Valve

TASK 21-63-52-000-001-A
Removal of the Pressure Regulating Valve

WARNING: MAKE SURE THAT AIR IS NOT SUPPLIED TO THE AIR CONDITIONING SYSTEM FROM THE MAIN ENGINE, THE APU OR A GROUND SOURCE. HOT COMPRESSED AIR CAN CAUSE INJURY TO PERSONNEL.

WARNING: MAKE SURE THAT THE COMPONENTS OF THE BLEED AIR SYSTEM ARE COOL. HOT COMPONENTS WILL BURN YOU.

WARNING: MAKE SURE THAT THE PNEUMATIC SYSTEM IS DEPRESSURIZED BEFORE YOU START WORK. PRESSURIZED AIR CAN CAUSE INJURY TO PERSONNEL.

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.

CAUTION: DO NOT PUT YOUR WEIGHT ON THE DUCTS. IT IS VERY EASY TO BREAK THEM.

FIN: 14HK

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	AR	CAP - BLANKING
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
825

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 25-54-12-000-001-A	Removal of the Forward Cargo-Compartment Partition
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 06-41-53-00	FUSELAGE-DESCRIPTION AND OPERATION
Pressure Regulating Valve ** ON A/C NOT FOR ALL
Pressure Regulating Valve ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 21-63-52-861-050-A

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

Subtask 21-63-52-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
** ON A/C NOT FOR ALL
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS2	4HK	V20
122VU	AIR COND/ZONE TEMP CTL/28VDC/SYS1	3HK	V19
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS2	2HK	V18
122VU	AIR COND/ZONE TEMP CTL/115VAC/SYS1	1HK	V17
** ON A/C NOT FOR ALL
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/115VAC	53HH	W22
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/28VDC	55HH	W21
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/115VAC	49HH	X22
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/28VDC	51HH	X21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20
122VU	AIR COND/TEMP CTL SYS 1/CHAN B/115VAC	50HH	Y18

Subtask 21-63-52-941-051-A

C. Safety Precautions
(1) On the panel 30VU:
(a) Make sure that:

the APU BLEED pushbutton switch is in the off position (the ON legend is off) and,
the ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are in the off position (the OFF legends are on).

(b) Put a warning notice in position to tell persons not to operate these pushbutton switches.
(2) On the HP and the LP ground connector put a warning notice in position to tell persons not to supply the ground air.

Subtask 21-63-52-010-050-A

D. Get Access
(1) Put the ACCESS PLATFORM 2M (6 FT) in position at the forward cargo-compartment door 825.
(2) Open the forward cargo-compartment door 825 (Ref. AMM TASK 52-30-00-860-001).
(3) Remove the access panels at partition FR34 (Ref. AMM D/O 06-41-53-00), (Ref. AMM TASK 25-54-12-000-001).

4. Procedure
Subtask 21-63-52-020-051-B ** ON A/C NOT FOR ALL

A. Removal of the Pressure Regulating Valve

Pressure Regulating Valve ** ON A/C NOT FOR ALL

(1) Disconnect the electrical connectors (1), (2) and (3).
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(3) Disconnect the control tube (4) from the pressure regulating valve (30) and from the check valves [7270HM] and [7272HM]
(4) Disconnect the control tube (5) from the pressure regulating valve (30).
(5) Put the PLUG-BLANKING in each disconnected line end.
(6) Remove the nut (10), the washer (9), the screw (6), the washer (7) and disconnect the bonding strap (8).
(7) Remove the clamps (26) and (28) and the duct assembly (27).
(8) Remove and discard the O-ring (25).
(9) Put blanking plugs on the open ends of the duct flange (29) and the duct assembly (27).
(10) Hold the pressure regulating valve (30) and remove the clamp (31).
(11) Remove the pressure regulating valve (30) and the O-ring (25). Discard the O-ring (25).
(12) Put blanking plugs on the open ends of the duct flange (24) and the pressure regulating valve (30).

Subtask 21-63-52-020-051-C ** ON A/C NOT FOR ALL

A. Removal of the Pressure Regulating Valve

Pressure Regulating Valve ** ON A/C NOT FOR ALL

(1) Disconnect the electrical connectors (1) and (2).
(2) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(3) Disconnect the control tube (4) from the pressure regulating valve (30) and from the check valves [7270HM] and [7272HM]
(4) Disconnect the control tube (3) from the pressure regulating valve (30).
(5) Put the PLUG-BLANKING in each disconnected line end.
(6) Remove the nut (9), the washer (8), the screw (5), the washer (6) and disconnect the bonding strap (7).
(7) Remove the clamps (26) and (28) and the duct assembly (27).
(8) Remove and discard the O-ring (25).
(9) Put blanking plugs on the open ends of the duct flange (29) and the duct assembly (27).
(10) Hold the pressure regulating valve (30) and remove the clamp (31).
(11) Remove the pressure regulating valve (30) and the O-ring (25). Discard the O-ring (25).
(12) Put blanking plugs on the open ends of the duct flange (24) and the pressure regulating valve (30).

[Rev.10 from 2021] 2026.03.31 23:09:45 UTC