5. Close OXYGEN SUPPLY valve V-6. Bleed
the test stand using SYSTEM BLEED valve V-5.
Close TEST PRESSURE GAUGE-TO-BELL
JAR valve V-2.
6. Remove the converter assembly from test
FILL AND BUILDUP TIME TEST
To perform the fill and buildup time test, it
will be necessary to take the converter to a LOX
servicing area, or use a LOX servicing trailer in
the immediate area of the oxygen shop. Any other
method is acceptable that meets requirements of
the test, and does not violate safety precautions.
Remember, LOX requires special precautions.
Once the converter is in a satisfactory loca-
tion, proceed as follows:
1. Attach a vent drain line to the converter
quick-disconnect coupling. This line should be
long enough to route venting LOX away from all
2. Attach the pressure gauge/relief valve test
fixtures to the supply quick-disconnect coupling
(refer to NAVAIR 13-1-6.4).
3. Attach the servicing trailer filler valve to
the converter fill, buildup, and vent valve.
4. Note the time, and start filling the
converter. Maintain a filling pressure at 30 psig.
5. The converter is full when a steady stream
of LOX flows from the drain line. When the
converter is full, note the time. The time required
to fill the converter at 30 psig should be no longer
than 10 minutes. Record the fill time in the
appropriate space on the Performance Test Sheet.
6. Note the time, and disconnect and secure
the servicing trailer. The time noted at this point
is the beginning of the buildup time test.
7. Observe the pressure gauge on the quick-
disconnect coupling. On the performance test
sheet, record the time it takes the converter
assembly to buildup to a working pressure of 70
to 80 psig. This time should not exceed 5 minutes.
8. If discrepancies were noted in either part
of the test, locate the probable cause using the
troubleshooting chart (table 12-21).
9. Remove the vent drain line and the pressure
gauge/relief valve test fixture you installed in steps
1 and 2.
CAPACITANCE TEST (FULL)
The capacitance test requires simultaneous use
of the 50-pound scales and the quantity gauge
capacitance type tester incorporated in the test
stand. Ensure the scales are positioned close
enough to the tester, then proceed as follows:
1. Place the full converter on the scales.
2. Using the test stand cable assembly,
connect the upper terminals of the converter high
and low capacitance cable assemblies to terminals
A and B, respectively, of the liquid oxygen
quantity gauge capacitance type tester.
3. Turn the power ON and allow the tester
to warm up 10 minutes before proceeding.
4. Turn the CAPACITANCE RANGE
SELECTOR knob to its 10X position.
5. Turn the FUNCTION SELECTOR knob
to the CAPACITANCE (UUF) position.
6. Enter the total weight of the full converter
in the space provided on the performance test
7. Subtract the tare weight of the converter
from its total weight. Enter this figure on the
Performance Test Sheet. This is the weight of
LOX in the converter.
8. Using the formula given on the Perform-
ance Test Sheet, 2.33 x W + 124.7 = C(max),
calculate the capacitance maximum (C-max). Use
the weight of LOX for W. Enter the result of the
calculation in the space provided.
9. Use the formula 2.25 x W + 122.3
= C(min) and calculate the capacitance minimum
(C-tin) on the next line of the test sheet. Use the
weight of LOX for W.
Table 12-21.Troubleshooting (Fill and Buildup Time Test)