SHD-138 Manual
6
3/16" WHEN PISTON IS UP
ITEM PART DESCRIPTION
QTY. ITEM PART DESCRIPTION
QTY.
1
26804 LOW PRESSURE INTAKE MANIFOLD R70
2
9
0521 WASHER 0.25 LOCK
12
1A
26807 HIGH PRESSURE INTAKE MANIFOLD R70
2
10
7493 GASKET UNLOADER VALVE R70
2
2
7481 CYLINDER UNLOADER VALVE R70
4
11
3
26812 UNLOADER PISTON R70
4
12
4
7483 O'RING UNLOADER VALVE R70
4
13
5
13924 PISTON ROD LP UNLOADER VALVE R70
2
14
5A
13925 PISTON ROD HP UNLOADER VALVE R70
2
6
4567 CLAW UNLOADER VALVE LP R70
2
6A
13921 CLAW UNLOADER VALVE HP R70
2
7
13922 SPRING UNLOADER VALVE LP R70
2
7A
13923 SPRING UNLOADER VALVE HP R70
2
8
1056 NUT 0.25-28 HH
8
17252 COMPRESSION FITTING
2
C5568 UNLOADER VALVE CONRADER
1
7499
COMPRESSION FITTING R70
1
C6064 U BOLT 0.25X1.25X2.25
1
13735 UNLOADER VALVE ASM LP R70
2
13736
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UNLOADER VALVE ASM HP R70
2
1 (LP)
1A (HP)
11
14
12
13
11
CAUTION
When re-installing head unloader the
actuating claw (Ref. No. 6) protrudes 3/16”
below the bottom of the manifold (Ref. No.
1) as shown. Claw must be position so that
it will enter three slots in the compressor
valve. Failure to follow this procedure will
result in an inoperative head unloader.
Air Pilot Valve Adjustment
(See Air Pilot Valve Adjustment Detail)
High Pressure Adjustment:
Proceed with the following
while the compressor is running.
1.) Loosen locknut (4) and back off several turns. Do
not turn differential adjuster (3).
2.) Check reading on the tank pressure gauge. Set the
compressor maximum pressure at 175 psi. Over
pressurizing compressor will cause damage and void
warranty. Turn threaded cap (1) clockwise to increase
pressure or counterclockwise to decrease pressure.
3.) After pressure is set, tighten locknut
4.) Be careful not to move the threaded cap (1).
Differential Pressure Adjustment:
Proceed with the
following while the compressor is running.
1.) Loosen locknut (2) and back off several turns.
2.) Check reading on the tank pressure gauge. Set the
pressure to 30 psi differential (unload at 175 psi, reload
at 145 psi). Turn nut (3) clockwise to increase
differential pressure or counterclockwise to decrease
differential pressure.
3.) After pressure is set, tighten locknut (2). Be careful
not to move nut (3)
Head Unloading System