Installation of the Thermocouple (APS 3200)

TASK 49-72-15-400-002-A
Installation of the Thermocouple (APS 3200)

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	Torque wrench: range to between 56 and 51 lbf.in (0.63 and 0.58 m.daN )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-00-00-710-008-A	Operational Test of the APU
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
Thermocouple

3. Job Set-up
Subtask 49-72-15-860-053-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) On the panel 25VU, make sure that the APU MASTER SW pushbutton switch is off.
(2) Make sure that there is a warning notice in the cockpit to tell persons not to start the APU.
(3) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).
(4) Make sure that the access platform is in position below the APU compartment.
(5) Make sure that the APU access doors are open (Ref. AMM TASK 52-41-00-010-001).

Subtask 49-72-15-865-054-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

4. Procedure
Subtask 49-72-15-420-051-A ** ON A/C NOT FOR ALL

CAUTION: -YOU MUST NOT INCREASE THE TIGHTENING TORQUE MORE THAN THE MAXIMUM VALUE.

APPLY ALL TIGHTENING TORQUES WITH A TORQUE WRENCH OR A CALIBRATED SCREWDRIVER.

A. Installation of the Thermocouple

NOTE: There are two thermocouples. The procedure is the same for each of the thermocouples.
Long thermocouple TC1 P30 (1) is installed on the RH side (FD) of the APU and short thermocouple TC2 P31 (2) is installed on the LH side (FD) of the APU.

(1) Install the short thermocouple TC2 P31 (2) or the long thermocouple TC1 P30 (1) with the bolt (3).
(2) TORQUE the bolt (3) to between 56 and 51 lbf.in (0.63 and 0.58 m.daN )

.
(3) Attach the cables of the thermocouples to the clamps (5) and install the clamps (5) and (6) with the bolts (4).
(4) TORQUE the bolts (4) to between 56 and 51 lbf.in (0.63 and 0.58 m.daN )

.
(5) Remove the CAP-BLANKING from each electrical connector and receptacle.
(6) Make sure that all the electrical connections are clean and in the correct condition.
(7) Connect long thermocouple TC1 P30 (1) or short thermocouple TC2 P31 (2) to the mount bracket.

Subtask 49-72-15-865-055-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-72-15-710-050-A ** ON A/C NOT FOR ALL

C. Test
(1) Do the operational test of the APU (Ref. AMM TASK 49-00-00-710-008).

5. Close-up
Subtask 49-72-15-410-051-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 APU access doors 315AL 316AR (Ref. AMM TASK 52-41-00-410-001).
(3) Remove the access platform(s).
(4) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:32:08 UTC