HEAT EXCHANGERS - REMOVAL/INSTALLATION
1. General
A. Each pack has a primary and secondary heat exchanger located between two sections of the ram air duct in the air conditioning equipment bay (Fig. 401). Removal/Installation procedures for the heat exchanger are similar. The following procedure is for either with any difference noted in the applicable step.
2. Equipment and Materials
A. Primer, RTV 1200 (20-30-11)
B. Adhesive, RTV 174 (20-30-11)
C. Solvent - Final Cleaning of All Organic Coatings Prior to Non-structural Bonding (Series 89) (Ref AMM /SOPM 20-30-89).
3. Remove Heat Exchanger
A. Open ram air duct access door and air conditioning equipment bay doors.
B. Remove ram air inlet duct inspection doors.
C. Remove V-band clamps connecting heat exchanger to air conditioning ducts.
D. For right heat exchanger, remove section of turbofan duct assembly under heat exchanger to provide clearance for removal (Fig. 401).
E. Remove section of air cleaner purge line from under heat exchangers to provide clearance for removal of heat exchanger (Detail B, Fig. 401).
F. Remove V-band clamp outboard of 35°F control valve, and clamp downstream of valve at V-joint. Remove section of duct.
G. Remove screws securing heat exchanger inlet lip and remove inlet lip.
H. Remove screws securing heat exchanger to lower wing beam.
I. Disconnect heat exchanger from duct (Fig. 401).
(1)
For secondary heat exchanger remove nuts, bolts, washers and lower spacer connecting the heat exchanger to flexible duct except two bolts which connect the heat exchanger to the support rod clip assembly. Remove stiffening flanges from either side of flexible duct.
(2)
For primary heat exchanger remove all nuts, bolts and washers connecting heat exchanger to ram air outlet duct except those attached to the support rod clip assembly. Remove stiffening flange from between heat exchanger and ram air exhaust duct.
J. Support heat exchanger and remove fasteners connecting clip assembly to heat exchanger.
K. Remove heat exchanger.
4. Prepare Heat Exchanger for Installation
A. Check that gasket bonded to lower wing beam is not damaged. If damaged, replace.
B. Remove gasket.
(1) Remove gasket and adhesive with putty knife or similar tool with a medium sharp edge. Clean the remaining adhesive with solvent, Series 89 (Ref AMM/SOPM 20-30-89).
C. Install gasket.
(1)
Brush a liberal coat of RTV 1200 primer on bonding surfaces.
(2)
Allow a minimum of 30-minute drying time.
(3)
Apply a uniform layer of RTV 174 adhesive.
(4)
Join surfaces as soon as possible after application of adhesive to prevent formation of skin on adhesive.
NOTE: Apply sufficient pressure to ensure complete contact but not enough to squeeze out an excessive amount of adhesive.
(5)
Allow 24 hours drying at 70 to 80°F. Optional cure time is 45 to 60 minutes at 200 to 250°
535
May 01/98 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 21-51-21 Page 401
Heat Exchanger Installation 531
21-51-21 Figure 401 (Sheet 1) Feb 15/71
Page 402
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
531 Heat Exchanger Installation
Feb 15/71 Figure 401 (Sheet 2) 21-51-21
Page 403
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
F.
5. Install Heat Exchanger
A. Support heat exchanger in position and install nuts, bolts, washers and upper spacer for secondary heat exchanger connecting clip assembly to heat exchanger.
B. Connect heat exchanger to duct.
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