Removal of the Low Oil Pressure Switch [CFMB]

TASK 79-34-15-000-041-A
Removal of the Low Oil Pressure Switch

FIN: 4000EN ** 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	CONTAINER 10 L(2 1/2 USGAL)
No specific	AR	COVER - PROTECTION
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
Low Oil Pressure Switch

3. Job Set-up
Subtask 79-34-15-941-050-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 79-34-15-865-065-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ANTI ICE/PROBES/AOA/1	4DA1	D04
49VU	ANTI ICE/PROBES/PITOT/1	3DA1	D02
122VU	ANTI ICE/PROBES/2/TAT	1DA2	Y15
122VU	ANTI ICE/PROBES/2/PITOT	3DA2	Y14
122VU	ANTI ICE/PROBES/2/AOA	4DA2	Y13
122VU	ANTI ICE/PROBES/2/STATIC	5DA2	Y11
122VU	ANTI ICE/PROBES/3/PITOT	3DA3	Z16
122VU	ANTI ICE/PROBES/3/AOA	4DA3	Z15
122VU	ANTI ICE/PROBES/3/STATIC	5DA3	Z14
122VU	ANTI ICE/PROBES/1/STATIC	5DA1	Z13
122VU	ANTI ICE/PROBES/1/TAT	1DA1	Z12

Subtask 79-34-15-865-066-A ** ON A/C NOT FOR ALL

WARNING: OPEN THE PROBE HEATER AND WINDOW HEATER CIRCUIT-BREAKERS BEFORE YOU OPEN THE PHC AND WHC CIRCUIT BREAKERS. IF YOU DO NOT OBEY THIS SEQUENCE:

THE PROBES WILL BECOME TOO HOT.
THIS CAN CAUSE DAMAGE TO EQUIPMENT AND INJURY TO MAINTENANCE PERSONNEL.

C. Open, safety and tag these circuit breakers in this sequence:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
49VU	ANTI ICE/PROBES/PHC/1	2DA1	D03
122VU	ANTI ICE/WHC/2	5DG2	W13
122VU	ANTI ICE/WHC/1	5DG1	X13
122VU	ANTI ICE/PROBES/PHC/3	2DA3	Y16
122VU	ANTI ICE/PROBES/PHC/2	2DA2	Y12

Subtask 79-34-15-010-050-A ** ON A/C NOT FOR ALL

D. Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 79-34-15-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the Low Oil Pressure Switch
(1) Cut and remove the safetywire from the insulation housing (15). Remove the housing from the low oil pressure switch (25).
(2) Cut and remove the safetywire from the Low Pressure (LP) bootie (5) and the High Pressure (HP) bootie (10). Remove the booties from the tubes.
(3) Disconnect the electrical connector 4000ENA from the pressure switch (25).
(4) Put a CONTAINER 10 L(2 1/2 USGAL) below the pressure switch (25) to collect the drained oil.
(5) Disconnect the tubes from the unions (40) in the pressure switch (25).
(6) Remove the bolts (35) and the washers (30) that attach the pressure switch (25) to the bracket.
(7) Remove the pressure switch (25) and the thermo barrier (20) from the engine.
(8) Remove the unions (40) and packings (45) from the pressure switch (25). Discard the packings.
(9) Put COVER - PROTECTION on the pressure switch, the tubes and the unions.

[Rev.10 from 2021] 2026.04.01 03:39:48 UTC