2. Using LOW PRESS. REGULATOR (N),
adjust the inlet pressure to 90 psig. Close OUT-
PUT valve (C).
3. Read the PRESS/SUCTION manometer
(4). The reading must be between 0.50 and 3.5
in H2O. Enter this reading in the appropriate
block of the performance test sheet.
4. Adjust OUTPUT valve (C) to a flow of
100 lpm and read the PRESS/SUCTION
manometer (4). The reading must also be between
0.50 and 3.5 in H2O. Enter this reading on the
test sheet also.
5. Increase the altitude to 43,000 feet, as
shown on the HIGH RANGE ALTM. (12), and
repeat steps 1 through 3. The readings on
PRESS/SUCTION manometer (4) must be
between 9.2 and 12.5 in H2O.
6. Increase the altitude to 50,000 feet. The
readings must be between 14.0 and 18.0 in H2O
at this altitude.
7. After the completion of this test, leave
OUTPUT valve (C) slightly open, and open
CHAMBER BLEED valve (K) and return to sea
8. Open the chamber door and close valve
(C). Turn off the vacuum pump.
9. Turn ON/OFF valve (L) to OFF, and
remove the regulator from the test stand.
10. Close the N2 supply cylinder and, using
LOW PRESS. REGULATOR (N) and SYSTEM
BLEED valve (S), relieve all the pressure in the
test stand. Secure all the test stand valves.
11. If the aneroid should need adjusting,
loosen the aneroid lockscrew using a .035 Allen
wrench and adjust the aneroid assembly using re-
taining pliers in accordance with the pressure
breathing test troubleshooting table 12-2.
NOTE: Remember we are discussing the
model 29267-A1 regulator only. For other
models of the CRU-79/P miniature
regulator, you must refer to the NAVAIR
After the completion of all the tests, you must
purge the regulator with aviators breathing
oxygen for 1 to 3 minutes at 90 psig to the
NEVER BLOCK THE OUTLET OF THE
MINIATURE REGULATOR WHILE
PRESSURE IS APPLIED TO THE
INLET. THIS WILL SERIOUSLY
DAMAGE THE REGULATOR.
After completion of the oxygen purge, place the
regulator in a plastic bag for storage.
The MD-1, CRU-52/A, CRU-54/A, CRU-
55/A, CRU-57/A, MD2, and CRU-72/A shown
in figures 12-3 and 12-4 are panel-mounted,
automatic, positive pressure diluter demand-type
regulators, and they are used in conjunction with
the pressure breathing type oxygen mask. The
regulators provide 100-percent oxygen, or an
air/oxygen mixture at the correct ratio, depending
Figure 12-3.Aircraft panel mounted oxygen regulator,
MD-1 (low pressure).
Figure 12-4.-Aircraft panel mounted oxygen regulator,
MD-2 (high pressure).