SECTION 7: TROUBLESHOOTING
CAS40P 40 CFM / 100 PSIG
PAGE - 62
®
An Oshkosh Corporation Company
Abnormal pressure fluctua-
tions (continued)
Pressure switch incorrectly set
May need to be replaced or reset; consult
Service Department for reset instructions.
Pressure switch faulty
Replace; consult Service Department for
reset instructions.
Hydraulic supply problems
Refer to
Compressor runs slow
section of
this table.
Pressure relief valve(s)
open continuously
Defective air pressure gauge
Replace gauge (
Section 8.6, Part 2 of 4
).
Damaged, worn, or leaking valve
Replace valve (
Section 6.4.17
).
Pressure switch set too high
May need to be replaced or reset; consult
Service Department for reset instructions.
Compressor recycles too
frequently
Air line leak
Inspect and replace hose or tighten con-
nections.
Pressure switch differential setting
is too small
May need to be replaced or reset; consult
Service Department for reset instructions.
Pressure switch faulty
Replace; consult Service Department for
reset instructions.
Excessive moisture in receiver
tank
Drain tank; check/drain on more frequent
interval to prevent moisture build-up.
Discharge air valve leaking
Replace.
Compressor will not shut
OFF or unload
Pressure switch faulty (if it does
not remove power from the sole-
noid valve)
Replace; consult Service Department for
reset instructions.
Solenoid valve does not operate
(no power to solenoid valve)
Replace solenoid valve (
Section 8.9
[12V]
, or
Section 8.10 [24V]
).
Air line leak
Inspect and replace hose or tighten con-
nections.
Oil in discharge air
Air intake restricted
Change air filters (
Section 6.4.4
).
Compressor crankshaft overfilled
Drain to correct level.
Compressor crankcase has oil
with the wrong viscosity
Drain crankcase and refill with the correct
oil (
Section 6.4.3
).
Continued on next page
7.2 TROUBLESHOOTING GUIDE
MALFUNCTION/FAULT
POSSIBLE CAUSE
CORRECTIVE ACTION
Manual #99905382 Rev 02
(JUNE 2018)
