Troubleshooting Chart - DeVilbiss AGX-550 Service Manual

TROUBLESHOOTING
Proper gun adjustment will result in normal spray patterns, from
round with the fan control valve (23) closed, to long and narrow
with the valve open. Pattern width depends upon how much
the valve is opened, the type of air cap used and fluid flow rate.
PROBLEM
Will not spray.
Improper spray pattern
A B C
Jerky or fluttering spray
Fluid leaking from needle
packings (11).
Dripping from fluid tip.
Air Leakage from Control
Valve (23)
SB-2-624-X (6/2017)

TROUBLESHOOTING CHART

CAUSE
No pressure to gun.
Piston stops moving.
New air packing (20)
A. Gun not adjusted properly.
A,B. Material build up on the air
cap or fluid tip.
To determine where the material build up is, rotate the air cap 180° and test spray. If the
pattern stays in the same position, the condition is caused by material build up on the fluid
tip. If the pattern changes with air cap movement, the build up is in the air cap.
D
C,D. Wrong material or material too
thick.
D. Insufficient material or atomizing
air pressure too high.
Insufficient material in the
tank or an obstruction in the line.
Gun material passage plugged.
Worn packings (11).
Loose or damaged fluid tip.
Needle packings (11) worn.
Rough or worn fluid needle shaft.
Worn or damaged fluid tip (3)
or needle (28).
Piston springs (30) and/or (31)
damaged or deformed.
Check to verify only one air packing
(20) is installed in piston.
Worn seals.
NORMAL SPRAY PATTERN
The proper combination of fluid pressure, fan and
atomization air pressure, and fluid tip size should
result in a pattern of this shape.
CORRECTION
Check air and material lines.
Check tightness of socket screws (7).
Remove fluid needle (28) and lubricate
with petroleum jelly and reassemble.
Re-adjust. See "Operation Section".
Clean the air cap or fluid tip. See
"Preventive Maintenance".
Note
C,D. Adjust material pressure or thin material.
D. Increase material or reduce atomizing
air pressure.
Fill tank or clear obstruction.
Clean.
Replace.
Tighten or replace.
Replace.
Polish contact point where packings (11)
makes contact with very fine emery cloth
or replace.
Replace.
Replace.
Remove extra.
Replace valve. (23).
7 / 12
EN
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