TM 5-4310-343-35
(c) Run compressor unit at 3750 50 rpm.
(d) Shut down compressor unit, drain oil from sump, then refill oil sump with 350 cc of filtered oil
(Specification FSN 9150-753-4667).
(e) Start compressor unit and run free breathing at 3750 50 rpm with 3000 psi back pressure. Run for
16 hours and record temperature and case drain leakage. Temperature shall be between 100 and 130F. Case drain
leakage shall not exceed 160 cc per minute at any time during test. At conclusion of 16th hour, the case drain leakage
shall not exceed a 60 cc increase from amount recorded at first hour.
(f) Shut down compressor, drain oil sump and measure quantity of remaining oil.
Oil consumption
should not have exceeded 7 cc per hour.
(8) Air Flow Check. Check that the compressor unit delivers 4.0 scfm minimum at sea level inlet conditions.
The compressor unit should be operating at 3750 50 rpm with 3000 psi delivery pressure; and atmospheric conditions
should be 30.6 inches mercury absolute and 70 to 90F ambient air temperature.
(9) Pump-Up Test. With compressor unit operating as indicated in paragraph (7), a 200 cubic inch system
connected to the compressor discharge port should be filled from 0 to 3000 psi in 6.74 minutes maximum.
(10) Bleed Valve and Moisture Separator Blow-Down.
(a) When compressor stops, check that bleed valve blows down. This "blow down" is the unloading of he
pressure in the 4th stage and the aftercooler and results in an audible blast of air (from the bleed valve under the
compressor) approximately one minute after compressor stops.
(b) When compressor stops, check that moisture separator blows down. This "blow do wn" follows that of
the bleed valve, and is the unloading of the air pressure from the check valve back to the separator. The accumulated
moisture in the separator discharges with the escaping air with an audible blast from a port just under the moisture
separator.
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