Removal of the Heat Exchanger Unit (from the Aircraft)

TASK 21-52-24-000-001-A
Removal of the Heat Exchanger Unit (from the Aircraft)

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: BE CAREFUL WHEN YOU REMOVE OR INSTALL THIS EQUIPMENT. THIS EQUIPMENT IS HEAVY (MORE THAN 12 KG (26.5 lb)) AND CAN CAUSE INJURY AND/OR DAMAGE.

NOTE: The procedure is the same for heat-exchanger units 10HM4 and 11HM4.

ZONE: 190
FIN: 10HM4
FIN: 11HM4

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	CAP - BLANKING
No specific	AR	PLUG - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	1	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
190	BELLY FAIR, AIR CONDITIONING & HYD COMPT
FOR [10HM4] (HEAT EXCHANGER UNIT)
191KB
FOR [11HM4] (HEAT EXCHANGER UNIT)
192KB

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-52-23-000-001-A	Removal of the Pipe Assembly between the Main Heat Exchanger and the Air Cycle Machine
TASK 21-52-24-200-001-A	Attachment Components (In-Service Wear Limits) - Heat Exchanger
TASK 21-61-52-000-003-A	Removal of the Ram-Air Outlet
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 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from the Belly Fairing Structure
Heat Exchanger Unit - Component Location ** ON A/C NOT FOR ALL
Heat Exchanger Unit - Component Location ** ON A/C NOT FOR ALL
Heat Exchanger Unit - Component Location ** ON A/C NOT FOR ALL
Heat Exchanger Unit - Component Location ** ON A/C NOT FOR ALL
Heat Exchanger Unit - Component Location ** ON A/C NOT FOR ALL
Attachment Components - Heat Exchanger Unit

3. Job Set-up
Subtask 21-52-24-861-051-A

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

Subtask 21-52-24-865-050-A

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 10HM4 (HEAT EXCHANGER UNIT)
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
** ON A/C NOT FOR ALL
121VU	IGGS/CTRL	7YA	N28
** ON A/C NOT FOR ALL
121VU	IGGS/CTRL	7YA	P28
** ON A/C NOT FOR ALL
122VU	AIR COND/PACK TEMP/CTL SYS1/1/115VAC	1HH	X22
122VU	AIR COND/PACK TEMP/CTL SYS1/1/28VDC	3HH	X21
122VU	AIR COND/PACK TEMP CTL SYS2/1/28VDC	4HH	Y19
122VU	AIR COND/PACK TEMP CTL SYS2/1/115VAC	2HH	Y18
** ON A/C NOT FOR ALL
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 1/CHAN B/115VAC	50HH	Y18
** ON A/C NOT FOR ALL
122VU	CSAS / CTRL	1HW	U17
** ON A/C NOT FOR ALL
FOR FIN: 11HM4 (HEAT EXCHANGER UNIT)
122VU	AIR COND/PACK TEMP/CTL SYS1/2/115VAC	21HH	W22
122VU	AIR COND/PACK TEMP/CTL SYS1/2/28VDC	23HH	W21
122VU	AIR COND/PACK TEMP CTL SYS2/2/28VDC	24HH	Y21
122VU	AIR COND/PACK TEMP CTL SYS2/2/115VAC	22HH	Y20
** 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 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20

Subtask 21-52-24-010-051-A

C. Get Access
(1) Remove these access panels from the belly fairing structure (Ref. AMM TASK 53-35-13-000-002):
(a) FOR [10HM4] (HEAT EXCHANGER UNIT)

191KB.

(b) FOR [11HM4] (HEAT EXCHANGER UNIT)

192KB.

(2) Remove the ram-air outlet (Ref. AMM TASK 21-61-52-000-003).
(3) Remove the pipe assembly (Ref. AMM TASK 21-52-23-000-001).

Subtask 21-52-24-941-052-A

D. Safety Precautions
(1) In the cockpit, on the overhead panel, on the AIR COND section of panel 30VU:
(a) Make sure that:

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

(b) Put a WARNING NOTICE(S) in position to tell persons not to operate these pushbutton switches.
(2) On the HP ground connector, put the WARNING NOTICE(S) in position to tell persons not to supply the ground air.

4. Procedure
Subtask 21-52-24-020-051-A ** ON A/C NOT FOR ALL

A. Removal of the Heat Exchanger Unit
(1) Remove the clamp (5), and disconnect the bellows (6).
(2) Remove the clamp (12), and disconnect the sleeve (13).
(3) Remove the clamp (14), and move the duct (15) and the sleeve (16) to the heat exchanger unit (7).
(4) Remove the clamp (2), and move the sleeve (3) away from the heat exchanger unit (7).
(5) Remove the nut (33), the washer (32) and the screw (31).
(6) If necessary, disconnect the bonding straps (34) and (41).
(7) Hold the hexagonal part of the retaining cables (75), (90) and (96), and remove and discard the nuts (74) and the washers (73).

NOTE: The retaining cables (75), (90) and (96) will twist, if you do not hold the hexagonal part of the retaining cables (75), (90) and (96).

(8) Disconnect the retaining cables (75), (90) and (96) from the flanges (17), (10) and (4).
(9) Remove the sleeve (88).
(10) Remove and discard the seals (87).
(11) Move the sleeves (72) and (79) away from the heat exchanger unit (7).
(12) Remove the heat exchanger unit:

WARNING: SUPPORT THE UNIT/ASSEMBLY. THE UNIT/ASSEMBLY IS HEAVY. IF YOU DO NOT SUPPORT IT, IT WILL FALL. THIS CAN CAUSE INJURY TO PERSONS, AND/OR DAMAGE TO EQUIPMENT.

(a) Hold the heat exchanger unit (7), and remove the nuts (54), washers (55), bolts (56), (if necessary, washers (57)) and bushes (58).
(b) Remove the nut (35), washer (36), bolt (40), (if installed, washer (39)) and bush (38).
(c) Disconnect the support rods (83), (82) and (80) and carefully remove the heat exchanger unit (7).

NOTE: The heat exchanger unit weighs approximately 40 kg (88.18 lb).

(13) Remove the sleeve (16) together with the duct (15).
(14) Remove the duct (15) from the sleeve (16).
(15) Remove the sleeves (72) and (79) from the flange (70) and the pipe assembly (91).
(16) Remove and discard the seals (71 (77)) and (84 (184)) or the seals (85 (185)) and (86 (186)) from the sleeves (16), (72) and (79).
(17) Hold the hexagonal part of the retaining cables (92), and remove and discard the nuts (74) and the washers (73).

NOTE: The retaining cables (92) will twist, if you do not hold the hexagonal part of the retaining cables (11).

(18) Disconnect the retaining cables (92) from the flange (76) and remove the pipe assembly (91).
(19) Remove the screw of the clamp (97).
(20) Carefully bend the clamp (97) and remove it.
(21) Remove the sleeve (78).
(22) Remove and discard the seals (77).
(23) Turn the sleeve when you disconnect it.
(24) Put the PLUG-BLANKING in each disconnected line end.
(25) Remove the nut (45), washer (44), bonding strap (41) and screw (42).
(26) If necessary, remove the nut (67), washer (68), bonding strap (34) and screw (69).
(27) Remove the inlet plenum (46):
(a) For the left heat-exchanger unit (10HM4):
1 Remove the nuts (50), washers (49), screws (48), inlet plenum (46) and seals (43) and (47).
(b) For the right heat-exchanger unit (11HM4):
1 Remove the nuts (50), washers (49), screws (48), inlet plenum (46) and seals (143) and (147).
(28) Put a protective cover on the cooling elements of the heat exchanger unit (7).
(29) Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate as follows:
(a) If one of the air-conditioning pack identification-plate/air-conditioning pack amendment-plate is installed:
1 Remove the screws (52).
2 Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate (53) from the heat exchanger unit (7).
3 Keep the removed items for the installation procedure.

NOTE: The air-conditioning pack identification-plate/air-conditioning pack amendment-plate contains the serial number and the part number for the air conditioning pack.

(b) If the air-conditioning pack identification-plate and the air-conditioning pack amendment-plate are installed:
1 Remove the screws (52).
2 Remove the air-conditioning pack identification-plate (51) from the heat exchanger unit (7).
3 Remove the air-conditioning pack amendment-plate (53) from the heat exchanger unit (7).
4 Keep the removed items for the installation procedure.

NOTE: The air-conditioning pack identification-plate and the air-conditioning pack amendment-plate contain the serial number and the part number for the air conditioning pack.

Subtask 21-52-24-020-051-C ** ON A/C NOT FOR ALL

A. Removal of the Heat Exchanger Unit
(1) For the left heat-exchanger unit (10HM4):
(a) Do not remove the seals from the duct ends.
(b) Remove the clamps (202) and the sleeves (201).
(c) Remove the nuts (208) and the washers (207).
(d) Hold the ducts (203) and (204) and the bonding strap (205) to remove the screws (210) and the washers (209).
(e) Remove the ducts (203) and (204) and the bonding straps (205) and (206).
(f) Remove and discard the seals (231).
(2) Put the PLUG-BLANKING in each disconnected line end.

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.

(3) For the left heat-exchanger unit (10HM4):
(a) Disconnect the electrical connectors (211), (212) and (213).
(b) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(4) Remove the clamp (12), and disconnect the sleeve (13).
(5) Remove the clamp (14), and move the duct (15) and the sleeve (16) to the heat exchanger unit (7).
(6) Remove the clamp (2), and move the sleeve (3) away from the heat exchanger unit (7).
(7) Remove the nut (33), the washer (32) and the screw (31).
(8) If necessary, disconnect the bonding straps (34) and (41).
(9) Hold the hexagonal part of the retaining cables (75), (90) and (96), and remove and discard the nuts (74) and the washers (73).

NOTE: The retaining cables (75), (90) and (96) will twist, if you do not hold the hexagonal part of the retaining cables (75), (90) and (96).

(10) Disconnect the retaining cables (75), (90) and (96) from the flanges (17), (10) and (4).
(11) Remove the sleeve (88).
(12) Remove and discard the seals (87).
(13) Move the sleeves (72) and (79) away from the heat exchanger unit (7).
(14) Remove the heat exchanger unit:

WARNING: SUPPORT THE UNIT/ASSEMBLY. THE UNIT/ASSEMBLY IS HEAVY. IF YOU DO NOT SUPPORT IT, IT WILL FALL. THIS CAN CAUSE INJURY TO PERSONS, AND/OR DAMAGE TO EQUIPMENT.

(a) Hold the heat exchanger unit (7), and remove the nuts (54), washers (55), bolts (56), (if necessary, washers (57)) and bushes (58).
(b) Remove the nut (35), washer (36), bolt (40), (if necessary, washer (39)) and bush (38).
(c) Disconnect the support rods (83), (82) and (80) and carefully remove the heat exchanger unit (7).

NOTE: The heat exchanger unit weighs approximately 40 kg (88.18 lb).

(15) Remove the sleeve (16) and the duct (15).
(16) Remove the duct (15) from the sleeve (16).
(17) Remove the sleeves (72) and (79) from the flange (70) and the pipe assembly (91).
(18) Remove and discard the seals (71 (77)) and (84 (184)) or the seals (85 (185)) and (86 (186)) from the sleeves (16), (72) and (79).
(19) Hold the hexagonal part of the retaining cables (92), and remove and discard the nuts (74) and the washers (73).

NOTE: The retaining cables (92) will twist, if you do not hold the hexagonal part of the retaining cables (92).

(20) Disconnect the retaining cables (92) from the flange (76) and remove the pipe assembly (91).
(21) Remove the screw of the clamp (97).
(22) Carefully bend the clamp (97) and remove it.
(23) Remove the sleeve (78).
(24) Remove and discard the seals (77).
(25) Turn the sleeve when you disconnect it.
(26) Put the PLUG-BLANKING in each disconnected line end.
(27) Remove the nut (45), washer (44), bonding strap (41) and screw (42).
(28) If necessary, remove the nut (67), washer (68), bonding strap (34) and screw (69).
(29) Remove the inlet plenum (46) and (230) as follows:
(a) For the left heat-exchanger unit (10HM4):
1 Remove the nuts (224), washers (225), screws (220), (223) and (226), bonding straps (221), (222) and (227), inlet plenum (230) and seal (228).
(b) For the right heat-exchanger unit (11HM4):
1 Remove the nuts (50), washers (49), screws (48), inlet plenum (46) and seals (143) and (147).
(30) Put a protective cover on the cooling elements of the heat exchanger unit (7).
(31) Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate as follows:
(a) If one of the air-conditioning pack identification-plate/air-conditioning pack amendment-plate is installed:
1 Remove the screws (52).
2 Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate (53) from the heat exchanger unit (7).
3 Keep the removed items for the installation procedure.

NOTE: The air-conditioning pack identification-plate/air-conditioning pack amendment-plate contains the serial number and the part number for the air conditioning pack.

(b) If the air-conditioning pack identification-plate (51) and the air-conditioning pack amendment-plate (53) are installed:
1 Remove the screws (52).
2 Remove the air-conditioning pack identification-plate (51) from the heat exchanger unit (7).
3 Remove the air-conditioning pack amendment-plate (53) from the heat exchanger unit (7).
4 Keep the removed items for the installation procedure.

NOTE: The air-conditioning pack identification-plate/air-conditioning pack amendment-plate contains the serial number and the part number for the air conditioning pack.

Subtask 21-52-24-020-051-E ** ON A/C NOT FOR ALL

A. Removal of the Heat Exchanger Unit
(1) For the left heat-exchanger unit (10HM4):
(a) Do not remove the seals from the duct ends.
(b) Remove the clamps (202) and the sleeves (201).
(c) Remove the nuts (208) and the washers (207).
(d) Hold the ducts (203), (204) and the bonding strap (205) and remove the screws (210) and the washers (209).
(e) Remove the ducts (203) and (204) and the bonding strap (205) and (206).
(f) Remove and discard the seals (231).
(2) Put the PLUG-BLANKING in each disconnected line end.

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.

(3) For the left heat-exchanger unit (10HM4):
(a) Disconnect the electrical connectors (211), (212) and (213).
(b) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(4) Remove the clamp (12), and disconnect the sleeve (13).
(5) Remove the clamp (14), and move the duct (15) and the sleeve (16) to the heat exchanger unit (7).
(6) Remove the clamp (2), and move the sleeve (3) away from the heat exchanger unit (7).
(7) Remove the nut (33), the washer (32), and the screw (31).
(8) If necessary, disconnect the bonding straps (34) and (41).
(9) Remove and discard the nuts (74) and the washers (73) from the retaining cables (75), (90) and (92).

NOTE: Hold the hexagonal part of the retaining cables (75), (90) and (92) will twist, if you do not hold the hexagonal part of the retaining cables (75), (90) and (92).

(10) Disconnect the retaining cables (75), (90) and (92) from the flanges (17), (10) and (4).
(11) Remove the sleeve (88).
(12) Remove and discard the seals (87).
(13) Move the sleeves (72) away from the heat exchanger unit (7).
(14) Remove the heat exchanger unit:

WARNING: SUPPORT THE UNIT/ASSEMBLY. THE UNIT/ASSEMBLY IS HEAVY. IF YOU DO NOT SUPPORT IT, IT WILL FALL. THIS CAN CAUSE INJURY TO PERSONS, AND/OR DAMAGE TO EQUIPMENT.

(a) Hold the heat exchanger unit (7) and remove the nuts (54), washers (55), bolts (56), (if necessary, washers (57)) and bushes (58).
(b) Remove the nut (35), washer (36), bolt (40), (if necessary, washer (39)) and bush (38).
(c) Disconnect the support rods (83), (82) and (80) and carefully remove the heat exchanger unit (7).

NOTE: The heat exchanger unit weighs approximately 40 kg (88.18 lb).

(15) Remove the sleeve (16) together with the duct (15).
(16) Remove the duct (15) from the sleeve (16).
(17) Remove the sleeves (72) from the flange (70).
(18) Remove and discard the seals (71 (77)) and (84 (184)) or the seals (85 (185)) and (86 (186)) from the sleeves (16), (72) and (79).
(19) Hold the hexagonal part of the retaining cables (92), and remove and discard the nuts (74) and the washers (73).

NOTE: The retaining cables (92) will twist, if you do not hold the hexagonal part of the retaining cables (92).

(20) Disconnect the retaining cables (92) from the flange (76), and remove the pipe assembly (91).
(21) Discard the seals (77).
(22) Put the PLUG-BLANKING in each disconnected line end.
(23) Remove the nut (45), washer (44), bonding strap (41) and screw (42).
(24) If necessary, remove the nut (67), washer (68), bonding strap (34) and screw (69).
(25) Remove the inlet plenums (46) and (230) as follows:
(a) For the left heat-exchanger unit (10HM4):
1 Remove the nuts (224), washers (225), screws (220), (223) and (226), bonding straps (221), (222) and (227), inlet plenum (230) and seal (228).
(b) For the right heat-exchanger unit (11HM4):
1 Remove the nuts (50), washers (49), screws (48), inlet plenum (46) and seals (143) and (147).
(26) Put a protective cover on the cooling elements of the heat exchanger unit (7).
(27) Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate as follows:
(a) If one of the air-conditioning pack identification-plate/air-conditioning pack amendment-plate is installed:
1 Remove the screws (52).
2 Remove the air-conditioning pack identification-plate/air-conditioning pack amendment-plate (53) from the heat exchanger unit (7).
3 Keep the removed items for the installation procedure.

NOTE: The air-conditioning pack identification-plate/air-conditioning pack amendment-plate contains the serial number and the part number for the air conditioning pack.

NOTE: The air-conditioning pack identification-plate and the air-conditioning pack amendment-plate contain the serial number and the part number for the air conditioning pack.

Subtask 21-52-24-020-053-A

B. Removal of the Attachment Components

Attachment Components - Heat Exchanger Unit

(1) Record the positions of the support rods to use in the installation procedure.
(2) Remove the nuts (54), washers (55), bolts (56), (if installed, washers (57)), bushings (58) and support rods (80), (82) and (83).
(3) Do the inspection of the components for in-service wear (Ref. AMM TASK 21-52-24-200-001).

[Rev.10 from 2021] 2026.04.02 06:11:28 UTC