DeVilbiss GTI-620S Service Manual

GTI-620S COMPLIANT HIGH VOLUME LOW PRESSURE
IMPORTANT: Before using this equipment,
read all safety precautions and instructions.
Keep for future use.
DESCRIPTION
These compliant high volume low pressure
suction feed GTI guns are designed to
®
apply a wide variety of finishing materials.
The guns were manufactured to provide
maximum transfer efficiency by limiting air
cap pressure to 10 psi (complies with rules
issued by SCAQMD and other air quality
authorities).
These guns will produce approximately 10
psi cap pressure at 30 psi gun inlet pres-
sure. Air cap test kits are available (see
ACCESSORIES) which can be utilized to set
the exact air cap pressure. Air consumption
for the GTI 600S (#100 cap) is 16 SCFM at
10 psi air cap pressure. Air consumption for
the GTI-620S (#2000 cap) is 15.5 SCFM at 10
psi air cap pressure.
Note
These guns include 300 series
stainless steel fluid tips and
needles. Guns may be used with
chlorinated solvent materials. See
page 2 for additional warnings.
Important: These guns may be used with
most common coating and finishing materi-
als. They are designed for use with mildly
corrosive and non-abrasive materials. If
used with other high corrosive or abrasive
materials, it must be expected that frequent
and thorough cleaning will be required and
the necessity for replacement of parts will
be increased.
INSTALLATION
For maximum transfer efficiency, do not use
more pressure than is necessary to atomize
the material being applied.
1. Connect the gun to a clean, moisture
and oil free air supply using a hose
size of at least 5/16" I.D. hose. Do not
use 1/4" I.D. hose (25' x 1/4" hose at 18
CFM has a pressure loss of 25 psi. 25'
x 5/16" hose at 18 CFM has a pressure
loss of 8 psi).
Note
Depending on hose length, larger
I.D. hose may be required. Install an
HAV-501 air gauge at the gun handle
and air cap test kit over tip. When
gun is triggered on, adjust regu-
lated pressure to desired setting to
SUCTION FEED SPRAY GUN
provide a maximum of 10 psi at the
air cap. Do not use more pressure
than is necessary to atomize the ma-
terial being applied. Excess pressure
will create additional overspray and
reduce transfer efficiency.
Note
If quick connects are required, use
only high flow quick connects ap-
proved for HVLP use such as DeV-
ilbiss HC-4419 and HC-4719. Other
types will not flow enough air for
proper gun operation.
Note
If an air adjusting valve is used at the
gun inlet, use DeVilbiss Model HAV-
500 or HAV-501 or HAV-511. Some
competitive adjusting valves have
significant pressure drop that can
adversely affect spray performance.
Models HAV-500 and HAV-501 have
minimal pressure drop, which is
important for HVLP spraying.
2. Attach the suction feed cup to the mate-
rial inlet.
Note
Protective coating and rust inhibi-
tors have been used to keep the
gun in good condition prior to
shipment. Before using the gun,
flush it with solvents so that these
materials will be removed from
fluid passages.
OPERATION
Mix, prepare and strain the material to be
sprayed according to the paint maufacturer's
instructions.
Strain material through a 60 or 90 mesh
screen.
1. Fill the suction feed cup with the mate-
rial. Do not overfill. Make sure that the
cup lid vent hole is clear.
2. Open the spreader adjustment valve
(10) (Fan) by turning the valve stem
counterclockwise.
3. Open fluid adjusting screw (17) by
turning counterclockwise.
4. Turn on air supply and set gun inlet
pressure to lowest recommended
pressure for material being sprayed.
Spray a test area. Air pressure and
paint flow should be adjusted to pro-
vide a uniform dispersion of atomized
paint throughout the pattern. Keep
air pressure as low as possible to
SERVICE BULLETIN
SB-2-473-N
Replaces SB-2-473-M
Repair Kit KK-5058-2
minimize bounce-back and overspray.
Excessive fluid flow will result in heavy
center spray patterns. Inadequate flows
may cause the patterrn to split. See
TROUBLESHOOTING, Page 5, if any
problems occur. If finer atomization is
required, increase gun inlet pressure.
If a reduced fluid flow rate is required,
turn fluid adjusting screw (17) clockwise
until desired fluid flow is obtained.
See Spray Gun Guide, SB-2-001 latest
revision, for details concerning setup of
spray guns.
PREVENTIVE MAINTENANCE
To clean air cap and fluid tip, brush exterior
with a stiff bristle brush. If necessary to clean
cap holes, use a broom straw or toothpick
if possible. If a wire or hard instrument is
used, extreme care must be used to prevent
scratching or burring of the holes which will
cauase a distorted spray pattern.
To clean fluid passages, remove excess
material from cup, then flush with a suit-
able solvent. Wipe gun exterior with a
solvent dampened cloth. Never completely
immerse in solvent as this is detrimental to
the lubricants and packings.
Note
When replacing the fluid tip or
fluid needle, replace both at the
same time. Using worn parts can
cause fluid leakage. See Chart 2.
Also, replace the needle packing
at this time. Lightly lubricate the
threads of the fluid tip before reas-
sembling. Torque to 15-20 ft. lbs.
Do not overtighten the fluid tip.
To prevent damage to fluid tip (5) or
fluid needle (11), be sure to either
1) pull the trigger and hold while
tightening or loosening the fluid
tip, or 2) remove fluid needle ad-
justing screw (17) to relieve spring
pressure against needle collar.