Troubleshooting Guide - DeWalt DWMT70779 Guide D'utilisation

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 D
Defective Pattern likely cause
1. Dirty or damaged
air cap
2. Dirty or damaged
fluid tip
Heavy top or
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.
Air getting into paint
stream somewhere.
Example: Same
symptoms as a cup
running out paint.
Gun splitting

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.
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.
10
WalT technician or your dealer.
e
Defective Pattern likely cause
1. Fluid nozzle
cracked or worn
2. Leak at thread
of fluid nozzle
3. Leak at fluid needle
4. Needle packing
Spitting, irregular
worn out
or fluttering spray
5. Insufficient fluid in cup
6. Vent hole in
container cover clogged
Air back
Excessive air blowing
pressuring
back into cup.
into cup.
Unatomized 1. Material too heavy
or spattered
spray
2. Insufficient air
pressure
3. Fluid pressure
too high
4. Dried material on tip
of fluid nozzle or
air jets of air cap
Inadequate 1. Air needle partially
air delivery closed
2. Dried material in air
jets or air cap
3. Obstruction in air line
Excessive fog 1. Air pressure too high
for viscosity of fluid
Suggested remedy
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
1. Open control knob
2. Clean
3. Remove obstruction
1. Reduce air pressure and/or
open fluid control knob