TM 9-4940-427-14&P
MODEL 303C OIL & WATER SEPARATOR
MANUAL FOR
MIL-S-12928E CLASS II
The Model 303C is made up of the 303 Air Filter and two 18C-3R Air
(attached), which
Part Sheet
Regulators as shown on
provides an exploded view of both.
The 303 air filter section of the 303C is where the compressed air is
cleaned of contamination (dirt,rust,etc.) and moisture,which is generally a
mixture of oil and water. In operation, the unit should be drained daily.
This is accomplished at the drain cock (1-HC-320).
To insure maximum efficiency, the reusable filter element (1-303-19)
should be inspected at least every three months. This is accomplished as
follows:
1. Relieve the unit of air pressure.
2. Loosen the cap nuts (1-303-07), using 3/4" wrenches.
3. Remove the lower cap nut (1-303-07), bottom casting (1-303-02),
and filter housing (1-303-03).
The filter element (1-303-19) is an edge type filter and all the contami-
nation collects on the outside of the element. If it is excessive, remove
the element and clean. This is accomplished as follows:
Unscrew the upper cap nut (1--303--07) from the center rod
1.
(1-303-04). This removes the main baffle and filter assembly.
Clean the filter element in solvent.
2.
Install the main baffle and filter assembly by inserting the
3.
center rod (1-303-04) thru the upper casting (1-303-01) and
screwing on the upper cap nut (1-303-07) hand-snug.
4.
Install the filter housing (1-303-03), bottom casting (1-303-02),
and lower cap nut (1-303-07).
5.
Tighten upper and lower cap nuts (1-303-07) with wrench.
6.
The unit is now ready for service.
The 18C-3R is the air regulator section of the 303C, and it is here the
regulation of air pressure is accomplished through the operation of the thumb
screw (1-18-20). When the thumb screw is turned clockwise, the indicated pres-
sure on the gage (GA-160) will increase. To decrease the pressure, simply
turn the the thumb screw counterclockwise.
TO increase the life of the diaphragm (1-18-10), the thumb screw should
be turned counterclockwise until the gage reads zero when the unit is not in
operation for extended periods of time. It is good practice, for instance,
if the unit is not being used at night, to have the day crew leave the unit
set at zero.
Troubleshooting of the 18C-3R is generally confined to two areas--the
diaphragm (1-18-10) and the valve stem (1-18-09). If the gage (GA-160) is
acting erratically, and air is coming out of the relief hole in the bonnet
(1-18-02A), then the diaphragm is faulty. If the same condition exists and
air is not coming out of the above-mentioned relief hole, then the trouble
is in the valve stem. Generally, something is keeping it stuck open.
To check either part, the following procedure should be followed:
Remove all pressure from the unit.
1.
Unscrew the machine screws (1-18-21), and the unit will dis-
2.
assemble as shown on Parts List
1