Troubleshooting
311238ZAM
17
Erratic motor operation
Symptom
Cause
Check Procedure
Solution
Motor runs slow.
Icing.
Note: External icing is
normal.
Stop spraying for a few
minutes to see if motor speed
returns to normal.
Reduce pressure, cycle rate, or duty cycle of
motor, and/or turn the de-icing control knob
(62-
NXT112
) counter-clockwise to open.
Low-Noise motors will ice faster than De-ice
models. Convert to de-ice muffler by removing
diffuser (63-
15G689
) and deflector
(54-
15H179
).
Add coalescing filter with auto drain (
NXT093
)
if models w/ built in air controls
In-adequate air supply, line
size, and/or reducing QC
connections
Verify air supply and line size Increase air supply, remove any restricting
connecting devices Note: air line minimum size
of 3/4 in. should be used. See system manual
for air consumption data
Slow motor reversal. Plugged poppet muffler
(58-
120206
) on top cap
plate (1), and/or poppet
muffler (58-
120206
) in
bottom motor cover (3).
Remove poppet mufflers (58)
and check for proper
changeover.
Replace poppet muffler (58-
120206
) on top cap
plate (1), and/or poppet muffler (58-
120206
) in
bottom motor cover (3-
NXT302
).
Valve assembly is dry and
sticky.
Add oil to air filter cup or add an air line oiler.
Air motor “bounces”
at top or bottom of
the stroke.
Poppet pin seat has debris
or is damaged on top or
bottom poppet valve
(12-
NXT100
).
Clean or replace the bottom poppet valve
(12-
NXT100
) Note: Problem poppet is typically
opposite from where motor bounces, because
the opposite poppet valve is slightly leaking,
preventing proper changeover.
Piston valve seal damaged
or installed backward on
piston valve (119-
NXT142
).
Inspect piston valve for
damage and proper
orientation.
Replace valve body (103-
15H394
) or entire air
valve assembly (40-
120089
).
Valve body (103-
15H394
)
is cracked due to screws
(123-
120089
) being
over-torqued.
Replace valve body (103-
15H394)
or entire air
valve assembly (40-
120089
).
Motor runs below 10
psi air input
pressure Note: 20
psi (140 kpa, 1.4
bar) or greater
needed to run NXT
air motor.
Missing or damaged spring
loaded detent
(113-
NXT145
).
Remove air valve cover
(112-
16A038
) and check for
binding/sticking of spring
loaded detent (113-
NXT145
)
Note: be careful removing
gasket (106-
15H634
).
Replace spring loaded detent (113-
NXT145
).
Motor runs only at
50 psi (345 kpa, 3.4
bar) or greater.
Leaking flat gasket
(46-
253476
).
Remove outer valve cover
(47-
287844
) and verify four
3/8 -16 x 4" screws
(41-
120088
), are tight to 20
ft-lbs (27.1 N•m)
Replace flat gaskets (46-
253476
). Note: apply
grease to gasket surface prior to re-assembly.
Motor runs at 20 -
50 psi (140-345
kPa, 1.4-3.4 bar),
but stops if input air
pressure is 50 psi
(345 kpa, 3.4 bar) or
greater.
Two bumpers (59-
277366
)
installed below #4 main
piston.
Disassemble and inspect
Remove extra bumper (59-
277366
).
