pressure. Full flow should be 3.0 c.f.m. of air.
(3) With the cap (1) adjusted so that a full flow' f
(1) Connect the relief valve to a high pressure
3.0 c.f.m,. of air is relieved at 2,275 + 25 psi an-
d the relief valve reseats at 1,950 psi, lock the
Warning: Be extremely careful when
cap in place with locknut 47).
working with pneumatic equipment to
(4) With the relief valve adjusted and locked in
prevent injury to personnel and damage to
position, apply pressure slowly to 2,275 - 25 psi
property resulting from careless handling or
so that the relief valve is relieving full flow of 3.0
possible equipment failure.
c.f.m. Slowly decrease the inlet pressure to
testing in an assigned area, cleared of all
1,950 psi so that the relief valve reseats. Allow
unauthorized personnel. Make certain all
one minute for the relief valve to stabilize and
equipment is properly cleared and secured.
then determine leakage of the relief valve. The
Clamp all pneumatic equipment being
measured leakage for one minute shall not
tested firmly in a vise or other suitable
exceed 3 cc of air.
testing fixture. Do not attempt to adjust or
disassemble equipment under pressure.
(1) Position the preformed packing (3) onto the
Use a heavy metal shield, equipped with
relief valve (2).
suitable safety glass windows to protect
(2) Screw the relief valve (2) into the cap (6) of the
personnel whenever proof pressure testing.
between 3 to 5 pound-feet.
(2) Back off the locknut (7) and adjust the cap (1)
(3) Install the water separator on the frame (par.
until the relief valve is passing full flow at 2,275
+ 25 psi. Pressure cycle the valve slowly ten
times from full open to zero inlet
Section III. FAN GROUP
component in the fan guard section while the
24. Description and Function
The fan group consists of a fan, fan guard, and attaching
compressor is in operation.
hardware. The fan consists of five vanes shaped in
such a manner that in rotation the fan propels air over
(1) Remove the screws (5), washers (6) and the
the compressor. The fan guard consists of concentric
fan guard (4).
wire rings mounted on four brackets. The inner portion
(2) Secure the pulley on the gasoline engine to
of the fan guard is covered by a circular metal plate.
prevent rotation of the crank-shaft, unscrew the
When positioned and mounted on the compressor, the
nut (3), and remove the washer (2) and fan (1).
fan serves to move the cooling air in and around the
b. Cleaning and Inspection.
intercoolers. The fan guard prevents external
(1) Clean all metallic parts in ultrasonic cleaner.
(2) Inspect components for scratches, nicks,
protection for personnel and the fan itself.
distortion and other damage.
(1) Secure the pulley on the engine to prevent
Fourth echelon maintenance personnel are authorized to
rotation of the crankshaft. Position the fan (1,
replace the fan, fan guard, fan nut, and attaching
8) on the compressor crankshaft and
secure with the washer (2) and fan nut (3).
Torque the fan nut to 17 pound-feet.
Warning: Do not attempt removal of any