UNLOADER
ASSEMBLY
- H E A D
Fig. 10. Air Unloading of Intake
HP (0.56
HP (1.1
and Up.
The unloader pilot is located on the crankcase and is
connected to the unloader by a copper line. The
and
(0.37 and 0.56
units use a pilot that is
mechanically activated (see Fig. 11). All other units are
operated by oil pressure (see Fig. 12). Disassemble and
clean units if suspect. See PARTS LIST section for
repair kit numbers.
Fig. 11. Three-Way Valve
and
(0.37 and 0.56
Units.
Fig. 12. Hydraulic Unloader Assembly-l-IHP (0.75
Units and Larger.
PRESSURE REGULATING VALVE
(PRV) STATION
The
to
(0.25 to 1.5
units use a Honey-
well
or
PRV. For detailed maintenance
and repair information, see Form No. 75-2558.
The prv station used on the
(2.2
units is a
combination of a Pall-Trinity-Micro Corp. filter, and a
Norgren regulator and relief valve (see Fig. 15 and
Table 3).
To perform maintenance and repair work on the prv
station, shut off air supply
from
tank. Bleed down the
system by manually operating the drain (push red button
on drain valve).
CAUTION
All valves and dampers return to the normal posi-
tion when system is bled. Study job drawings for
critical problems before bleeding down system.
The regulator and relief valve can now be replaced or
repaired with the appropriate repair kit (see PARTS
section).
After repairing or replacing, slowly turn air back on,
checking for leaks.
75-7268
16