TROUBLESHOOTING DEFECTIVE SPRAY PATTERNS
The following procedure summarizes the steps that an
operator must immediately take when the first signs of a
defective spray pattern emerge.
1. Check the external portion of the fluid tip for material
buildup. If buildup has occurred, secure the gun
trigger safety switch and clean the gun fluid tip with a
non-metal soft brush.
2. If the spray pattern exhibits signs of tails at the top or
bottom ends of the pattern, increase the air pressure
gradually until the tails disappear.
3. If increasing air pressure does not dissipate the tails,
the fluid tip may be worn and may need to be
replaced. Another sign of the need to replace a worn
tip is a gradual decline in spraying pattern width.
4. If cleaning or replacing the fluid tip does not dissipate
the tails; the spraying defect is most likely due to the
material temperature and/or viscosity.
5. If pattern pulsation or blinking occurs, check the
pressure regulators, all downstream regulators, and the
pump. These may require further adjustment or even
repairs.
Figure 3
Correct
Pattern
Tails
GENERAL TROUBLESHOOTING
IMPORTANT REGULATORY NOTE
The AA4400M Air-Assist H.V.L.P. hand spray gun combines the proven efficiency of the Binks compliant spray guns with
air-assist atomization to yield a reliable, carefully engineered compliant spray gun. With 25' of 5/16" I.D. air hose and
regulator set at only 1.4 bar [20 psi] the compliant air cap registers 0.7 bar [10 psi] of atomization air to shape and soften the
spray pattern. The AA4400M air-assist H.V.L.P. gun operates at high transfer efficiencies and fully complies with all
government regulations for H.V.L.P. spray guns.
Max. Fluid Input: 303 bar [4400 psi]
Max. static air pressure at regulator with 25' of hose to inlet: 1.4 bar [20 psi]
Max. Dynamic Gun Inlet Air Pressure: 1 bar [14 psi]
Gun Body: Forged Aluminum Alloy
Fluid Path: Stainless Steel and Tungsten Carbide / PEEK
PROBLEM
CAUSE
ACTION
Fluid leaking from
through the seal
Worn seal or needle shaft.
Loose needle seal.
Replace needle assembly (18).
Tighten packing nut gently until leak stops.
Fluid leaking from the
front of the gun
Needle ball worn or damaged.
Worn seat assembly.
Replace needle assembly (18).
Replace fluid seat (3/3A).
Fluid in air passages
Spray tip seal leaking.
Leaking around fluid seat.
Tighten air cap/nozzle guard assembly (7)
Replace carbide tip assembly (5/5A).
Tighten or replace fluid seat (3/3A).
Slow fluid shut off
Fluid buildup on needle assembly.
Clean or replace needle assembly (18).
No fluid output when
triggered
Tip orifice plugged.
Needle is damaged or broken.
Fluid filter or fluid hose plugged.
For flat tip: Turn off fluid supply. Relieve pressure into a closed earth-
grounded container. Engage trigger safety. Remove air cap/nozzle
guard assembly (6) and the carbide tip (5). Clean or replace carbide
tip assembly (5).
For twist tip: Rotate twist tip (5A) in aircap (6A) and spray into a
closed-grounded container to try clear tip of any debris. If that fails
to unplug the tip then remove, clean and replace twist tip.
Turn off fluid supply. Relieve pressure into a closed-grounded
container. Remove trigger (10). Replace needle assembly (18)
Turn off fluid supply. Relieve pressure into a closed-grounded
container. Turn off air supply to pump and relieve fluid pressure with
bypass valve. Engage trigger safety. Very slowly loosen the hose
connection at the gun to relieve any pressure in hose. Remove hose
and clear obstruction. NOTE: When replacing filter, use two
wrenches—one to hold tube (11) in place and prevent twisting, and
the other to remove nut (14). Only tighten nut (14) from 12-15 N-m
[9 -11 ft.-lbs.]
(Refer to page 12 when referencing part numbers in brackets.)
CAUTION
Always engage trigger lock and relieve fluid pressure before
servicing gun.
!
EN
77-2922-R12 (4/2021)
5 / 16
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