TM 5-4310-369-14
e. Adjustment of Unloader Valve. (Figure 4-8)
Belt and Pulley Guard
(1) Start compressor unit and allow air pressure to
build up.
(2) Unloader valve should unload compressor at
Do not operate the air compressor with the
175 psi and reload compressor at 140 psi. If the above air
belt guard removed.
pressures are not achieved, adjust unloader valve.
(a) Loosen jam nuts (5 and 8).
removing screws.
(b) The unloading pressure can be adjusted by
b. Cleaning and Inspection.
nut (3). Turn clockwise to increase and counterclockwise
to decrease.
(c) The differential (difference between cut in
Drycleaning solvent, P-D-680, used to clean parts
and cut out pressure) is obtained by adjusting screw (6).
is potentially dangerous to personnel and property.
Turning clockwise will widen the differential and counter-
Avoid repeated and prolonged skin contact. Do
clockwise will narrow the differential.
(d) Repeat items b and c until desired settings are
not use near open flame or excessive heat. Flash
point of solvent is 100 (38C).
obtained.
(e) After adjustments are made, tighten nuts (5
(1) Clean all parts with cleaning solvent, item 5,
and 8).
(2) Inspect the V-belt guard and mounting brackets
Safety and Relief Valve
for dents, cracks or other damage. Straighten minor dents
a. Removal.
and bends in the guard and brackets.
(1) Release air from the air receiver tank by de-
(3) Inspect all attaching hardware for damaged
pressing handle on air hose inflator assembly until air tank
threads. Replace damaged attaching hardware and replace
gage reads 0 psi.
an unserviceable guard, bracket or other defective part.
(2) Remove the safety valve (4) from the air
receiver tank.
with screws.
b. Cleaning and Inspection.
Unloader Valve
Drycleaning solvent, P-D-680, used to clean parts
determined setting (approximately 175 psi [12.3 kg/sq cm]),
is potentially dangerous to personnel and property.
air is released to the unloader valve. When air pressure drops
Avoid repeated and prolonged skin contact. Do
to a predetermined setting (approximately 140 psi [9.8
kg/sq cm]) the unloader valve closes.
not use near open flame or excessive heat. Flash
b. Removal.
point of solvent is 100F (38C).
(1) Release the air from the air receiver tank by
(1) Clean all parts in cleaning solvent, item 5,
depressing handle on airhose inflator assembly until air
tank gage reads 30 psi or less. (Figure 4-7).
(2) Inspect all parts for breaks, cracks and other
(2) Remove the unloader valve (2) from the air
damage. Replace a defective part.
receiver tank.
c. Cleaning and Inspection.
NOTE
This valve is preset at 200 psi (14.16 kg/sq cm).
The internal parts of the safety valve cannot be
Drycleaning solvent, P-D-680, used to clean parts
repaired. Replace valve if defective.
is potentially dangerous to personnel and property.
c. Installation.
Avoid repeated and prolonged skin contact. Do
(1) Install the safety valve (4) in the fitting (14) on
not use near open flame or excessive heat. Flash
air receiver tank (1).
point of solvent is 100F (38C).
(2) Close draincock (5).
(1) Clean unloader assembly with cleaning solvent,
Interstage Safety Valve.
item 5, App. D. and dry thoroughly.
a. Removal. Remove the interstage safety valve (30)
(2) Examine mounting threads for defective threads
from the compressor high pressure cylinder head by turning
or cracks.
the valve counterclockwise.
(3) Replace defective unloader.
d. Installation. Install the unloader valve (2) in the air
receiver tank (1).
