(2)
For secondary heat exchanger install nuts, bolts, washers, stiffening flanges (if applicable) and lower spacer connecting heat exchanger to flexible duct as shown in view 1, Fig. 401.
C. Install bolts securing heat exchanger to lower wing beam.
D. Align heat exchanger with duct connections.
NOTE: Adjust length of support rods as required to have heat exchanger duct connections match with duct runs. After final adjustment, lockwire support rods.
E. Install duct section and V-band clamp outboard of 35°F control valve.
F. Align duct section and install clamp downstream of valve at Y-joint.
G. Install V-band clamps connecting heat exchanger to air conditioning ducts.
CAUTION: MAINTAIN 1/2-INCH CLEARANCE BETWEEN AIR CONDITIONING DUCT AND HEAT EXCHANGER TO PREVENT DUCT FROM RUBBING ON THE LOWER EDGE OF THE FORWARD HEAT EXCHANGER.
H. For right heat exchanger, install turbofan duct section.
I. Install section of air cleaner purge line.
J. Install heat exchanger inlet lip.
K. Install ram air inlet duct inspection doors.
L. Provide electrical power.
M. Pressurize pneumatic system to approximately 25 psi.
N. Operate air conditioning air cycle system.
O. Hold temperature selector to manual COOL until air mix valve moves to full COLD then move selector to OFF.
P. Check for leakage at all duct joints that were separated by listening and feeling. Diffused leakage is allowed at any connection but jet blasts are not.
Q. Turn air cycle system off.
R. Remove pneumatic power if no longer required.
S. Remove electrical power if no longer required.
T. Close air conditioning equipment bay and ram air duct access doors.
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HEAT EXCHANGER - ADJUSTMENT/TEST
1. General
A. Dirty or clogged heat exchangers may cause A/C pack overheat trip. Should problems occur, accomplish heat exchanger tests included in 21-00, Air Conditioning - Maintenance Practices.
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Nov 15/79 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 21-51-21 Page 501
HEAT EXCHANGERS - CLEANING
1. General
A. This procedure has one task. The task is to clean the primary and secondary heat exchangers of the air cycle system.
B. The heat exchangers are cleaned with a detergent that flows through the heat exchangers in the opposite direction of the ram air. Air from the APU or from a high pressure ground cart can be used to move the detergent through the heat exchangers.
2. Primary and Secondary Heat Exchangers Cleaning
A. Equipment and Materials
(1)
C21002-20 - Reverse Flusher - Heat Exchanger
(2)
PF80-012 - Deactivator - Check Valve, PF Industries Inc.
(3)
High Pressure Ground Cart
(4)
B00541 - Detergent, P-D-220, diluted with water as suggested by the manufacturer
B. Prepare to Clean the Heat Exchangers
(1)
Set the position of these switches on the forward overhead panel as follows:
(a)
Set the APU BLEED switch to OFF.
(b)
Set the L PACK and R PACK switches to OFF.
(c)
Set the ISOLATION VALVE switch to OPEN.
(2)
Make sure that the inlet doors and the exit louvers for the ram air are fully open.
(3)
Open the bay doors to the air conditioning equipment.
(4)
Open the access doors for the ram air duct.
(5)
Remove the two access panels to the heat exchangers.
(6)
Examine the exchangers to see if dirt or other unwanted material is on the inlet of the heat exchangers.
(a) Remove all unwanted material from the inlet of the heat exchangers.
(7)
Install the heat exchanger reverse flusher below the ram air exhaust louvers and against the airplane (Fig. 701).
(8)
Put a container of diluted detergent on the work stand, and make sure that the container is above the reverse flusher.
(9)
Install the quick-disconnect end of a hose to the fitting on the side of the reverse flusher.
(10)
Put the other end of the hose into the container with the detergent.
C. Clean the Heat Exchangers with the APU as the Pneumatic Source
(1) Use the APU as the pneumatic source to clean the heat exchangers as follows:
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