CAS40P 40 CFM / 100 PSIG
SECTION 6: MAINTENANCE
PAGE - 41
®
An Oshkosh Corporation Company
on plunger [
P
] and assemble with spring [
L
] into
inlet hold-down cover [
GG
] and [
K
] (refer to
Section 6.4.6.2
for part lubrication).
2. Assemble fingers [
H
] and [
FF
] and locknut [
G
]
to complete assembly.
3. Install hold-down cover assemblies with "O"
rings [
J
] and [
Y
] using cap screws [
M
].
Tighten evenly to a torque of 10 foot-lbs.
Connect unloader tube [
AA
] to tube elbow
[
R
] and tube tee [
CC
]. Connect tubing from
pilot valve to tube tee [
CC
].
6.4.6.2 LUBRICATION
When assembling plunger, [
P
] and “O” ring [
N
] to
hold-down cover [
GG
] and [
K
], coat “O” ring with sili-
con grease to facilitate assembly.
6.4.6.3 SERVICE
Dirt in unloader line or defective pilot valve could hold
valve open allowing unloading fingers to keep inlet
valves open. Sometimes tapping the pilot valve will
allow pilot valve to resume normal operation. If not,
remove, clean or replace. Also broken “O” ring [
N
]
may cause erratic operation. Refer to
unloader pilot
operation NOTE
and
Section
6.4.6, Compressor
Valve Maintenance
description for details.
6.4.7 CENTRIFUGAL UNLOADER INSTALLATION
To maximize the accessible work space needed for
compressor unit maintenance, both side panels
(drive assembly access panel and instrumentation
panel) must be removed. Consult
Section 6.4.1.2,
Removing and Replacing a Side Panel
to remove
the side panels.
WARNING
Before performing maintenance:
Shut down machine, relieve all system
pressure and lock out all power, as per
the Safety Section of this manual. If
machine is hot, allow package to cool
before removing any panel.
NOTE THAT THE SYSTEM CAN BE
STARTED REMOTELY:
Always clearly tag the start-up
instrumentation against accidental
system start-ups during maintenance.
IMPORTANT
Required, precise adjustments are
needed to perform maintenance on the
centrifugal unloader. IMT suggests
contacting the Service Department for
assistance when performing this
procedure.
NOTE
UNLOADER PILOT OPERATION:
The inlet valve unloaders are designed to
provide CONSTANT PRESSURE
CONTROL by holding open the inlet
valves in both cylinders. When the air
supply exceeds the demand and the
discharge pressure rises above the
maximum required, the pilot valve (not
shown) admits air at discharge pressure
to a plunger in each unloader, holding
the inlet valve discs off their seats. Thus
the air drawn into the cylinders is freely
discharged without being compressed.
When the pressure has dropped to the
desired minimum, the pilot valve closes,
allowing the inlet valves to seat and
compression to be resumed.
Manual #99905382 Rev 02
(JUNE 2018)
Summary of Contents for IMT CAS40P
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