SUBTASK 47-21-00-790-017
(2) On the control box of the test equipment, SPL-14094, do these steps:
CAUTION
KEEP THE PRESSURE IN THE LIMITS. NEGATIVE PRESSURE CAN
CAUSE DAMAGE TO THE TUBES.
(a) Adjust the AIR SUPPLY REGULATOR control to increase to get -4.0 psig (-27.6 kPa).
(b) Adjust the VACUUM REGULATOR control to decrease to get -4.5 psig (-31.0 kPa) to
-5.0 psig (-34.5 kPa).
SUBTASK 47-21-00-480-010
(3) Connect the other end of the hose assembly to the vacuum hose fitting on the control box of
the test equipment, SPL-14094.
(a) Set the VACUUM valve to the OFF position.
(b) Adjust the AIR SUPPLY REGULATOR control to decrease to the lowest position.
(c) Turn off the external air pressure.
SUBTASK 47-21-00-790-018
(4) Do the vacuum leakage test.
(a) Hold the vacuum pressure between 1 minute 50 seconds and 2 minutes 10 seconds.
(b) Make sure that the vacuum pressure reading on the gauge is between -4.5 psig
(-31.0 kPa) to -5.0 psig (-34.5 kPa).
1) Record the initial vacuum value from the gauge.
(c) Wait between 24 minutes and 26 minutes.
1) Record the final vacuum value from the gauge.
(d) Make sure that the air vacuum difference between initial and final values is between ± .20
psig (± 1.38 kpa).
(e) If the air vacuum difference between initial and final values is more than ± .20 psig (±
1.38 kpa):
1) Replace the primary backflow prevention check valve (TASK 47-21-04-000-801).
(f) Repeat the vacuum leakage test to make sure that the leak is repaired.
SUBTASK 47-21-00-980-005
(5) On the control box of the test equipment, SPL-14094, set the EXHAUST valve to the OPEN
position.
G. Put the Airplane Back to Its Usual Condition
SUBTASK 47-21-00-020-009
(1) In the left main wheel well, on the rear spar, disconnect one end of the hose assembly included
with the test equipment, SPL-14094 from the flame arrestor fitting.
SUBTASK 47-21-00-020-010
(2) Disconnect the other end of the hose assembly included with the test equipment, SPL-14094
from the vacuum hose fitting on the control box of the test equipment, SPL-14094.
SUBTASK 47-21-00-420-004
(3) Connect the dielectric hose to the flame arrestor.
737-600/700/800/900
AIRCRAFT MAINTENANCE MANUAL
47-21-00
Page 610
D633A101-ILF Oct 15/2019
ECCN 9E991 BOEING PROPRIETARY - Copyright © Unpublished Work - See title page for details
EFFECTIVITY
ILF 402, 452, 509, 510, 523, 525-528, 568, 569, 576, 577, 581, 583, 585, 588-590,
592-599, 601-603, 606, 607, 610-615, 620, 625-627, 691-699, 833-835, 838, 971, 980-999;
ILF 101, 151, 156-199, 301, 304, 308, 310, 314, 315, 317-319, 323, 331-399, 401, 405,
406, 409, 410, 412, 416, 424, 425, 427-429, 451, 501-504, 507, 508, 512-514, 516, 518,
524, 531-533, 535-537, 541, 542, 552-556, 560-562, 567, 571-575, 671, 672, 686, 703,
707-710, 803-813, 821, 822, 831, 832, 836, 837, 841, 842, 851, 852, 854-858, 861-863,
871-874, 947, 948, 968-970, 972, 973 POST SB 737-47-1003
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