Troubleshooting Guide - DeWalt DWMT70777 Instruction Manual

This section provides a list of the more frequently encountered malfunctions, their cause and corrective actions. The operator or maintenance personnel can
perform some corrective actions, and others may require the assistance of a qualified
Defective Pattern Likely cause
1. Dirty or damaged
air cap
2. Dirty or damaged
Heavy top or
fluid tip
bottom pattern
Air pressure too high for
material viscosity being
sprayed.
Split
pattern
1. Dirty or distorted air
horn holes.
2. One of the air horn
holes completely
obstructed.

TROUBLESHOOTING GUIDE

Suggested remedy
1. Rotate air cap 180°. If the
pattern follows the air cap,
the problem is in the air cap.
Clean and inspect the air cap.
If the pattern is not corrected,
replacement is necessary.
2. If pattern doesn't follow the air cap,
the problem is with the fluid tip.
Clean and inspect the tip for dried
paint, dirt or damage. If the pattern
is not corrected, replacement
is necessary.
1. Reduce air pressure.
2. Turn pattern control knob
clockwise to decrease fan width.
Turn fluid needle adjusting nut
counterclockwise to increase
fluid flow.
1. Rotate air cap 180°. If the
pattern follows the air cap,
the problem is in the air cap.
2. Clean and inspect the horn
holes. If the horn holes are
distorted, replacement is
necessary.
10
D WaLT
technician or your dealer.
e
Defective Pattern Likely cause
Air getting into paint
stream somewhere.
Example: Same
symptoms as a cup
running out paint.
Gun splitting
1. Fluid nozzle
cracked or worn
2. Leak at thread
of fluid nozzle
3. Leak at fluid needle
Spitting, irregular
4. Needle packing
or fluttering spray
worn out
5. Insufficient fluid in cup
6. Vent hole in
container cover clogged
Air back
Excessive air blowing
pressuring
back into cup.
into cup.
1. Material too heavy
2. Insufficient air
pressure
Unatomized
3. Fluid pressure
or spattered
too high
spray
4. Dried material on tip
of fluid nozzle or
air jets of air cap
Suggested remedy
1. Check and tighten fluid needle
packing nut.
2. Tighten fluid tip.
3. Check fluid tip seat for damage.
4. Check for poor gun to cup seating.
5. Check that cup is correctly
fastened on the gun.
1. Tighten or replace
2. Tighten fluid nozzle
3. Tighten compression nut assembly
or replace needle packing
4. Replace packing
5. Fill cup with fluid
6. Clean out
1. Tighten fluid tip.
2. Check fluid tip seat.
3. Check for damaged fluid seat
on tip or seat on gun head.
1. Thin material or use larger orifice
fluid nozzle set
2. Increase pressure to within limit
3. Reduce pressure
4. Clean