Troubleshooting - Air Motor
3A9121A
25
Troubleshooting - Air Motor
NOTE:
To find parts lists for the parts identified in the
troubleshooting tables, see page numbers listed in the
table below.
2. Check all possible causes and problems before
disassembling pump.
* To determine if fluid hose or gun is obstructed, follow
the
, page 10. Disconnect
fluid hose and place a container at pump fluid outlet to
catch any fluid. Turn on air power just enough to start
pump. If pump starts, the obstruction is in fluid hose or
gun.
Problem
Cause
Solution
Air motor will not run and there is no
obvious exhaust
Check air supply
Supply air to motor inlet.
Pump is locked up.
Disconnect or remove pump to
verify motor operation.
Ice broke loose in manifold and
caught in air valve.
Turn off and exhaust air. Push top
and bottom manual shuttle override
buttons (R) back and forth until flush
with base of valve cap (316). Restart
motor.
Air motor doesn't run and large
volume of air blows through exhaust
outlet on either stroke.
Main motor piston o-ring (6) has
failed or main valve. See below.
Replace piston o-ring (6). See
Air exhausts from rear outlet
continuously when motor is stalled
against fluid valve on one stroke or
the other.
Shuttle valve cup (313) and plate
(314) failure.
Replace shuttle valve cup (313) and
plate (314).
Motor stalled at bottom of stroke
with no exhaust at bottom pilot. No
exhaust at top pilot.
Bottom pilot valve (D) is not
exhausting. Usually ice in the pilot or
pilot exhaust port.
Disconnect pilot line (L) for that pilot.
If motor changes over, bottom pilot
is plugged. Replace pilot valve
and/or thaw ice that is blocking air
signal.
Metered air hole in main valve
shuttle piston (304) is plugged.
Disconnect pilot line (L). If motor still
doesn't change over, shuttle piston
metering hole is plugged. Clean or
replace shuttle valve piston
assembly (304).
Motor stalled at bottom of stroke
with exhaust at bottom pilot. Some
exhaust at top pilot.
Top pilot or fittings are leaking air
when not activated by motor piston.
Tighten fittings leak or replace top
pilot valve (D).