Removal of the Cabin Pressure Controller (CPC)

TASK 21-31-34-000-001-A
Removal of the Cabin Pressure Controller (CPC)

ZONE: 121
ZONE: 122
FIN: 11HL
FIN: 12HL

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	ACCESS PLATFORM 1M(3 FT)
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
121	AVIONICS COMPARTMENT
122	AVIONICS COMPARTMENT
811

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
Cabin Pressure Controller ** ON A/C NOT FOR ALL
Cabin Pressure Controller ** ON A/C NOT FOR ALL
Cabin Pressure Controller ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 21-31-34-861-050-A

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

Subtask 21-31-34-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
FOR FIN: 11HL (PRESS CONT 1)
49VU	AIR COND/CAB/PRESS/CTL1	1HL	D09
122VU	AIR COND/CAB PRESS/CTL/MAN	3HL	Y23
FOR FIN: 12HL (PRESS CONT 2)
122VU	AIR COND/CAB PRESS/CTL/MAN	3HL	Y23
122VU	AIR COND/CAB PRESS/CTL/2	2HL	Y22

Subtask 21-31-34-010-050-A

C. Get Access
(1) Put the ACCESS PLATFORM 1M(3 FT) in position at access door 811.
(2) Open access door 811.

4. Procedure
Subtask 21-31-34-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Cabin Pressure Controller
(1) Install the protective cap (6) on the pressure port of the controller (1).
(2) Loosen the nut (4).
(3) Lower the nut (4).
(4) Pull the cabin pressure controller (1) on its rack (3) to disconnect the electrical connector (2).
(5) Remove the cabin pressure controller (1) from its rack (3).
(6) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

Subtask 21-31-34-020-050-B ** ON A/C NOT FOR ALL

A. Removal of the Cabin Pressure Controller
(1) Install the protective caps (6) on the pressure ports of the controller (1) (for controller with P/N type 20791-0XXX).

NOTE: There are no protective caps on controller with P/N type 20791-1XXX.

(2) Loosen the nut (4).
(3) Lower the nut (4).
(4) Pull the cabin pressure controller (1) on its rack (3) to disconnect the electrical connector (2).
(5) Remove the cabin pressure controller (1) from its rack (3).
(6) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

Subtask 21-31-34-020-050-C ** ON A/C NOT FOR ALL

A. Removal of the CPC
(1) Install the protective cap (6) on the pressure port of the CPC (1).
(2) Loosen the nut (4) from the lug (5) of the CPC (1).
(3) Pull the CPC (1) to disconnect it from the electrical connector port (2).
(4) Remove the CPC (1) from the rack (3).
(5) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.

[Rev.10 from 2021] 2026.03.31 23:04:42 UTC