Removal of the Heat Exchanger Unit (From the Air Conditioning Pack)

TASK 21-52-24-000-001-A-01
Removal of the Heat Exchanger Unit (From the Air Conditioning Pack)

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.

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	PLUG - BLANKING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [10HM4] (HEAT EXCHANGER UNIT)
191BB, 191KB
FOR [11HM4] (HEAT EXCHANGER UNIT)
192FB, 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 21-52-41-000-001-A	Removal of the Air Conditioning Pack
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

3. Job Set-up
Subtask 21-52-24-010-052-A

A. 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)

191BB
191KB.

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

192FB
192KB.

4. Procedure
Subtask 21-52-24-020-052-A

A. Removal of 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.

(1) Remove the air conditioning pack (Ref. AMM TASK 21-52-41-000-001) from the aircraft and attach it to an applicable support stand:
(a) Make sure that the air conditioning pack is correctly attached to the support stand before you remove the pack components.

NOTE: Damage to the components could occur if it is not correctly supported.

(2) Remove the pipe assembly (Ref. AMM TASK 21-52-23-000-001).
(3) Remove the clamp (9) and the sleeve (8).
(4) Remove the nut (45), washer (44), bonding strap (41) and screw (42).
(5) Removal of 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).
(6) Put a protective cover on the cooling elements of the heat exchanger unit (7).
(7) If installed, remove the nut (67), washer (68), bonding strap (34) and screw (69).
(8) Loosen the clamp (12), and disconnect the sleeve (13).
(9) Remove the duct (15).
(10) Remove the sleeves (88) and (16):
(a) Turn the sleeves (88) and (16) when you move or remove them. This will help to prevent damage to the internal seals.
(11) Remove and discard the nuts (74) and the washers (73).
(12) Remove the retaining cables (96) from the flange (4).
(13) Disconnect the retaining cables (75) from the flange (17).
(14) Disconnect the retaining cables (90) from the flange (10).
(15) Carefully remove the heat exchanger unit (7) from the air condition pack:
(a) Get other person to support you.

NOTE: The heat exchanger unit weighs 36 kg (79.3664 lb).

(16) Put the PLUG-BLANKING in each disconnected line end.

[Rev.10 from 2021] 2026.03.31 23:07:03 UTC