Graco Series A Operation manual

INSTRUCTIONS–P ARTS LIST 307–860
Rev. D
Supersedes B
This manual contains IMPORT ANT
W
ARNINGS AND INSTRUCTIONS
READ AND RET AIN FOR REFERENCE
Model AS4000M
MANUAL ELECTROSTATIC METALLIC
AIR SPRA Y GUN
100 psi (7 bar) MAXIMUM WORKING PRESSURE
Part Number 221–179 Series A
With 180–739 air cap and 0.047 in. (1.2 mm)
fluid nozzle.
U.S. Patent No. 4,241,880, 4,335,851, and 4,721,255
Other U.S. and Foreign Patents Pending
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441
COPYRIGHT 1988 GRACO INC.

 

307-860ą3
TABLE OF CONTENTS
Terms 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How AS4000M Spray Gun W orks 3. . . . . . . . . . . . . . .
Safety W arnings 4, 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation
Typical Installation 6. . . . . . . . . . . . . . . . . . . . . . . . . . .
Warning Signs 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ventilate the Spray Booth 7. . . . . . . . . . . . . . . . . . . . .
Connect the High V oltage Cable 7. . . . . . . . . . . . . . .
Connect the Air Lines 7. . . . . . . . . . . . . . . . . . . . . . . . .
Connect the Fluid Line 7. . . . . . . . . . . . . . . . . . . . . . . .
Check the Electrical Grounding 8. . . . . . . . . . . . . . . .
Operation
Operating
Checklist 9. . . . . . . . . . . . . . . . . . . . . . . . . .
Filter the Fluid 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjust the Spray Pattern 10. . . . . . . . . . . . . . . . . . . . .
Flush the Spray Gun 10. . . . . . . . . . . . . . . . . . . . . . . .
Maintenance
Daily
Care and Cleaning 11. . . . . . . . . . . . . . . . . . . . .
Clean the Air Cap and Fluid Nozzle 11. . . . . . . . . . . .
Service
Spray
Pattern T roubleshooting Chart 12. . . . . . . . . .
Gun Operation T roubleshooting Chart 13. . . . . . . . .
Electrical T roubleshooting Chart 14, 15 . . . . . . . . . . .
Gun Disassembly 16. . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrode Replacement 16. . . . . . . . . . . . . . . . . . . . . .
Barrel Removal 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Packing Removal 18. . . . . . . . . . . . . . . . . . . . . .
Fluid Packing Replacement 18. . . . . . . . . . . . . . . . . .
Resistor Assembly Replacement 19. . . . . . . . . . . . . .
Fan Air V alve Replacement 20. . . . . . . . . . . . . . . . . . .
Air V alve Replacement 20. . . . . . . . . . . . . . . . . . . . . . .
Resistor Stud or Contact Replacement 21. . . . . . . . .
Parts Drawing 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts List 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Order Replacement Parts 23. . . . . . . . . . . . . .
Accessories 24, 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Repair Kits 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Data Back Cover . . . . . . . . . . . . . . . . . . . . . . .
Warranty Back Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TERMS
WARNING Alerts user to avoid or correct conditions that
could cause bodily harm.
CAUTION Alerts user to avoid or correct conditions that
could cause damage to or destruction of
equipment.
NOTE Identifies essential procedures or helpful
information.
HOW AS4000M SPRAY GUN WORKS
A transformer supplies high voltage current through the
cable to the gun’s ionizing electrode, where the
electrostatic field is developed. The pump supplies fluid
through the hose and gun, where it is electrostatically
charged
as it passes the electrode. The charged fluid is
attracted to the grounded work piece, wrapping around it
and coating all surfaces.

4 307-860
SAFETY W ARNINGS
SERIOUS BODILY INJURY, EXPLOSION, FIRE, OR ELECTRIC SHOCK
CAN OCCUR IF THE PRECAUTIONS BELOW ARE NOT FOLLOWED.
READ AND UNDERSTAND ALL INSTRUCTION MANUALS, TAGS,
AND WARNING LABELS BEFORE OPERATING EQUIPMENT.
ELECTROSTATIC EQUIPMENT SHALL ONLY BE USED BY TRAINED,
QUALIFIED PERSONNEL WHO SHALL BE FULLY CONVERSANT WITH
THE REQUIREMENTS STATED WITHIN THIS INSTRUCTION MANUAL.
EQUIPMENT MISUSE HAZARD
General Safety
Any misuse of the spray equipment or accessories, such as overpres -
surizing,
modifying parts, using incompatible chemicals and fluids, or us -
ing
worn or damaged parts, can cause them to rupture and result in seri -
ous
bodily injury , fire, explosion or property damage.
NEVER point the spray gun at anyone or at any part of the body . NEVER
put hand or fingers over the spray nozzle.
ALWAYS follow the Pressure Relief Procedure , at right, before cleaning
or removing the fluid nozzle or servicing any system equipment.
NEVER try to stop or deflect leaks with your hand or body .
NEVER
alter or modify any part of this equipment; doing so could cause it
to malfunction.
CHECK all spray equipment regularly and repair or replace worn or dam -
aged
parts immediately .
System Pressure
This gun has a maximum working pressure of 100 psi (7 bar). Never ex -
ceed the maximum working pressure of the gun or any other component
or accessory used in the system.
Fluid Compatibility
BE SURE all fluids and solvents used are chemically compatible with the
“Wetted Parts” shown in the TECHNICAL DA T A on the back cover . Al-
ways read the fluid and solvent manufacturer ’ s literature before using the
fluid or solvent in this gun.
Pressure Relief Procedure
To reduce the risk of serious bodily injury , including splashing in the eyes
or on the skin, injury from moving parts or electric shock, always follow
this procedure when shutting of f the system, when checking or servicing
any part of the spray system, when installing, cleaning or changing fluid
nozzles, and whenever you stop spraying.
1. T urn off the high voltage power supply .
2. T
urn of f the air and fluid supply to the gun.
3. Trigger the gun into a grounded metal waste container to relieve
fluid
pressure.
4. Open the pump drain valve, having a waste container ready to catch
the drainage.
5. Leave the pump drain valve open until you are ready to spray again.
HAZARDOUS FLUID HAZARD
Improper handling of hazardous fluids or inhaling vapors can cause ex -
tremely
serious bodily injury , even death, due to splashing in the eyes,
ingestion, inhalation, or bodily contamination. Know what fluid you are
pumping and its specific hazards. Store hazardous fluids in approved
containers. Dispose of any waste fluid according to all Local, State and
Federal regulations pertaining to the disposal of hazardous wastes. Ob -
serve all precautions when handling known or potentially hazardous flu -
ids,
including, but not limited to, the following.
1. Always wear appropriate, protective clothing and equipment, such as
eye protection, respiratory protection, and gloves.
2. Provide for the safe piping and disposal of all exhaust air .
3. Provide proper ventilation in accordance with accepted industry
standards and governmental regulations. Refer to Ventilate the
Spray
Booth , on page 5.
HOSE SAFETY
TIGHTEN all fluid connections securely before each use.
NEVER use a damaged hose. Before each use, check the entire hose for
cuts, leaks, abrasion, bulging cover , or damage or movement of the hose
couplings. If any of these conditions exist, replace the hose immediately .
HANDLE
AND ROUTE HOSES CAREFULL Y . Do not pull on hoses to
move equipment. Do not use fluids or solvents which are not compatible
with the inner tube and cover of the hose.


FIRE OR EXPLOSION HAZARD
All parts of the electrostatic spray system must be properly grounded to
reduce the risk of static electricity discharge. Static electricity is created
by the high velocity flow of fluid through the pump and hose and the spray
gun’s power supply. Ungrounded objects can become electrically
charged and sparking may occur. Sparks can ignite vapors from sol-
vents, fluid being sprayed, dust particles and other flammable sub-
stances,
which can cause a fire or explosion and result in serious bodily
injury and property damage.
If you experience any sparking or feel even a slight shock, STOP
SPRAYING IMMEDIATELY. Check for proper grounding of the entire
system.
Be sure you have corrected the problem before starting to spray
again.
The
minimum spraying distance from the gun nozzle to the work piece is
4 in. (100 mm). Holding the gun any closer to the work piece will cause
sparking.
Grounding
The following are minimum requirements for grounding a basic electro -
static system. Your system may include other equipment or objects
which
must also be grounded. Always check your local electrical code for
detailed grounding instructions. Be sure your system is connected to a
true earth ground.
1. Pump: ground by using a ground wire and clamp as described in
your separate pump instruction manual.
2. Air compressors: ground according to the manufacturer ’s recom -
mendations.
3. High voltage power supplies: must be properly grounded and lo -
cated outside the spray area. Ground according to the manufactur -
er’s
recommendations.
4. High voltage cable: obtain grounding through connection of an un -
damaged cable to a properly grounded power supply .
5. All electric cables going to the power supply must be properly
grounded.
6. Spray gun: obtain grounding through connection to properly
grounded high voltage cable.
7. Object being sprayed: keep the work piece hangers clean and
grounded
at all times. Contact points must be sharp points or knife
edges.
8. All electrically conductive objects or devices in the spray area, in -
cluding paint containers and wash cans, must be properly
grounded.
9. All persons entering the spray area: shoes must have conductive
soles, such as leather , or personal grounding straps must be worn.
Rubber or plastic soles are not conductive. The operator must not
wear gloves which insulate the hand from the spray gun. See page 9
for how to modify the glove.
10. The floor of the spray area must be electrically conductive and
grounded. Do not cover the floor with cardboard or any non–con -
ductive
material which would interrupt grounding continuity .
11. Flammable liquids in the spray area must be kept in approved,
grounded containers. Do not store more than the quantity needed
for one shift.
12. All solvent pails: use only grounded metal pails, which are conduc -
tive. Do not place the pail on any non–conductive surface, such as
cardboard or paper , which would interrupt grounding continuity .
Flushing and Cleaning Safety
To reduce the risk of static sparking or splashing, always follow the Pres-
sure
Relief Procedure on page 4 before flushing. Use the lowest possi -
ble
pressure and use a grounded metal waste container .
Be sure the high voltage power supply is OFF during flushing.
NEVER use solvents having a flash point of less than 70 _ F (21 _ C) to
clean the gun. NEVER use solvents having a flash point of less than 100 _
F (38 _C) to clean the spray system. AL WAYS remove all solvent from the
system before reactivating the spray gun.
Use only non–sparking tools to clean residue from the booth and hang -
ers.
Ventilate the Spray Booth
To prevent hazardous concentrations of toxic and/or flammable vapors,
spray only in a properly ventilated spray booth.
The High V oltage Power Supply must be electrically interlocked with the
ventilators to prevent operation of the Power Supply unless ventilating
fans are operating.
NEVER operate the spray gun unless the ventilating fans are operating.
IMPORTANT
United States Government safety standards have been adopted under the Occupational Safety and Health Act. These standards––particularly the
General Standards, Part 1910.107 and any other appropriate regulations––should be consulted in connection with the installation, operation, and
maintenance of electrostatic spray painting equipment.

6ą307-860
TYPICAL INSTALLATION
Connection for 75 KV Power Supply
KEY
AAir Supply Line
B Air & W ater Separator
C Ball V alve
D
Air Line Lubricator
E Air Regulator (bleed–type)
FPump
G Fluid Filter
H Remote Switch and Lights Wiring
J ON–OFF (D.P .–D.T .) Switch
K High V oltage Power Supply
(located outside the spray/hazardous area)
L Remote Switch & Lights
M Air Filter (5 micron)
N High V oltage Cable
O Fluid Regulator
P Fluid Line
Q Electrostatic Gun
R Atomizing Air Line
S Air Supply Shutof f V alve
(bleed–type)
T Fluid Drain V alve
NON–HAZARDOUS AREA
Power Supply Must Be Interlocked
W ith Spray Booth Exhaust Fan.
HAZARDOUS AREA
WARNING
SIGN
The Typical Installation shown above is only a guide for
selecting
and installing electrostatic air spray systems. It
is not an actual system design. The particular type and
size
system for your operation must be custom designed
for your needs. For assistance in designing a system,
contact
your Graco representative.
Warning Signs
Mount warning signs in the spray area where they can
easily be seen and read by all operators. See the AC–
CESSORIES section on page 25.
WARNING
Installing
and servicing this equipment requires ac -
cess to parts which may cause electric shock or
other serious bodily injury if the work is not per-
formed
properly . Do not install or service this equip -
ment
unless you are trained and qualified.
Be sure your installation complies with National,
State
and Local codes for the installation of electri -
cal
apparatus in a Class 1, Group D, Divisions 1 and
2 Hazardous Location.

307-860ą7
INSTALLATION
Ventilate the Spray Booth
WARNING
To prevent hazardous concentrations of toxic
and/or
flammable vapors, spray only in a properly
ventilated spray booth. The High Voltage Power
Supply must be electrically interlocked with the
ventilators to prevent operation of the power
supply unless the ventilation fans are operating.
NEVER OPERATE THE SPRAY GUN UNLESS
VENTILATION F
ANS ARE OPERA TING.
Check and follow all of the National, State and
Local codes regarding air exhaust velocity
requirements.
Check
and follow all local safety and fire codes and
OSHA standard 1910–107(b)(5)(i).
NOTE: High velocity air exhaust will decrease the
operating efficiency of the electrostatic system.
Air exhaust velocity of 100–150 ft/min (31–46
linear
meters/minute) should be suf ficient.
Connect the High Voltage Cable (Refer to the
Typical
Installation Drawing)
1. Connect one end of the High V oltage Cable (N) to the
gun (Q) in the spray booth area.
2. Insert the High V oltage Cable into the insulator tube
of the gun and tighten the cable with the retaining nut.
3. Route the High V oltage cable (N) from the gun to the
Power Supply (K). T o avoid permanent indentations
of the cable and cable failures caused by unneces-
sary
stress to the cable, be sure to take the following
precautions:
a. Support the cable overhead to avoid people
walking
on it and vehicles driving over it.
b. DO NOT clamp the cable too tightly at supports.
c. Avoid sharp kinks and bends in the cable.
4. Lubricate the cable o–rings with petroleum jelly. At-
tach
the cable to the Power Supply .
Connect the Air Lines (Refer to the T ypical
Installation Drawing)
1. Install an air line filter (M) to ensure a clean, dry air
supply
to the gun. Dirt and moisture in the air line can
ruin the appearance of your finished work piece, and
cause the Power Supply to malfunction.
2. Install an air line lubricator (D) as close to the pump
(F) as possible.
3. Install a bleed–type air regulator (E) on the pump and
gun air supply lines to control air pressure to the
pump
and gun.
4. Install a bleed–type air shutof f valve (S) on the main
air line and each gun air supply line to shut of f air to
the gun(s). Install an additional bleed–type valve on
each pump air supply line.
WARNING
The
bleed–type air shutoff valve is required in your
system to relieve air trapped between this valve
and
the pump after the valve is closed. T rapped air
can cause the pump to cycle unexpectedly , which
could result in serious bodily injury, including
splashing
in the eyes or on the skin and injury from
moving parts.
5. Connect an air supply line to the 1/4 npt(m) IN port on
the Power Supply air flow switch.
6. Connect an air line from the 1/4 npt(m) OUT port on
the air flow switch to the gun’ s 1/4 npsm(m) air inlet.
Connect the Fluid Line (Refer to the T ypical
Installation Drawing)
1. Before connecting the fluid line (P), blow it out with
air,
and flush it with solvent. Be sure the solvent you
use is compatible with the fluid to be sprayed.
2. Connect the fluid line from the outlet of the pump to
the 3/8 npsm(f) inlet of the gun.
3. Install a fluid filter (G) and drain valve (T) at the pump
outlet.
WARNING
The
fluid drain valve is required in your system to
assist in relieving fluid pressure in the
displacement
pump, hose and gun; triggering the
gun to relieve pressure may not be sufficient.
Install
a drain valve close to the pump’ s fluid outlet.
The drain valve reduces the risk of property
damage or serious bodily injury, including
splashing in the eyes or on the skin and
contamination
from hazardous fluids.
4. Install a fluid regulator (O) to control the fluid pres-
sure
to the gun.

8ą307-860
INSTALLATION
Check the Electrical Grounding (See Fig 1)
WARNING
Proper electrical grounding of every part of your
system is essential. For your safety, read the
warning section, FIRE OR EXPLOSION
HAZARD, on page 5. Ground the system as
explained there. Then check your system as
explained
below .
1. Make sure the High Voltage Power Supply is pro–
perly grounded and located outside the spray area.
The
Power Supply case and spray gun actuator can
become charged if the case is not well grounded. The
ground wire is part of the high voltage circuit and
must, without fail, be connected to a true earth
ground. As an added precaution, attach a separate
ground wire to the case of the High Voltage Power
Supply.
2. Shut of f the Power Supply and the air and fluid lines
to the gun.
3. Have a qualified electrician check the electrical
grounding
continuity of the spray gun. Use an ohm -
meter
(V) to measure resistance between the handle
of the gun (Q) and a true earth ground (U). The resis -
tance
should be less than 20 ohms.
WARNING
If the resistance is over 20 ohms, the gun is not
properly grounded, and the system may be haz-
ardous. Check again that you have properly
grounded
your system components; see FIRE OR
EXPLOSION HAZARD , on page 5. Since the gun
is grounded through connection to an undamaged,
properly grounded, high voltage cable and power
supply, check for a grounding problem with the ca -
ble
and power supply first. BE SURE you have cor -
rected
the problem before using the system.
Fig 1
U
KEY
QGun
UTrue
Earth Ground
VOhmmeter
Q
V

307-860ą9
OPERATION
WARNING
Pressure
Relief Procedure
To reduce the risk of serious bodily injury , including
splashing in the eyes or on the skin, injury from
moving parts or electric shock, always follow this
procedure when shutting off the system, when
checking
or servicing any part of the spray system,
when installing, cleaning or changing fluid nozzles,
and whenever you stop spraying.
1. T urn of f the high voltage power supply .
2. T
urn of f the air and fluid supply to the gun.
3. Trigger the gun into a grounded metal waste
container
to relieve fluid pressure.
4. Open the pump drain valve, having a waste
container
ready to catch the drainage.
5. Leave the pump drain valve open until you are
ready to spray again.
Operating Checklist
Check the following list daily, before starting to operate
the system, to help ensure you of safe, efficient
operation.
 Be sure all operators are properly trained to
safely operate an electrostatic air spray
system.
 Be sure all operators are trained how to prop-
erly
and completely relieve system pressure.
 Be sure the system is thoroughly grounded.
See
FIRE OR EXPLOSION HAZARD on page
5, and Check the Electrical Grounding on
page 8.
 Be sure the operator and all persons entering
the
spray area are properly grounded.
 Be sure ventilation fans are operating properly .
 Be sure the workpiece hangers are clean and
grounded.
Contact points must be sharp points
or knife edges.
 Be sure all refuse is removed from the spray
booth.
 Be
sure all flammable liquids in the spray booth
are in approved, grounded containers.
 Be sure all conductive objects within 20 ft (6 m)
of the gun are electrically grounded and the
floor
of the spray area is electrically conductive
and grounded.
 Be sure the operator’s glove is modified, if
used, so the operator’s hand will not be insu-
lated from the spray gun handle. See Fig 2.
Fig 2
or
2 Fingers of
Glove Cutoff
3 in. (76 mm)
Square Cutout
Filter the Fluid
Filter the fluid to remove coarse particles and sediment
which
could clog the spray nozzle.


OPERATION
Adjust the Spray Pattern
This gun can atomize many fluids with different viscosi-
ties and at various flow rates. Follow these steps to es-
tablish
the correct fluid flow and air flow:
1. Set the atomizing air pressure at 30 psi (2 bar) and
fluid
pressure at 3 to 4 psi (0.25 bar).
2. Choose the correct fluid nozzle and air cap combina -
tion for your application. See Instruction Manual
307–803
for the air cap consumption and fluid nozzle
flow rate information. Both flow rate and viscosity
must
be considered. A 0.047 in. (1.2 mm) fluid noz -
zle
is furnished with the gun.
3. Adjust the fluid flow by using the fluid pressure regu -
lator installed in the fluid line. (See the Accessories
section.)
4. For fine adjustment, use the fluid adjusting screw
(54)
located at the rear of the gun. See Fig 3. T urn it
clockwise to reduce the amount of fluid being
sprayed, and
counterclockwise to increase the
amount
being sprayed.
5. Use an air pressure regulator to adjust the pressure
for the desired degree of atomization. Always use the
lowest air pressure possible for the most efficiency.
See the Spray Pattern Troubleshooting Chart in
the Service Section.
6. Use the air adjusting screw (41) to change the shape
of the spray pattern. Turn it counterclockwise for a
wide
pattern and clockwise for a solid, round pattern.
Fig 3
KEY
41 Air Adjusting Screw Assembly
54 Fluid Adjusting Screw Assembly
54
41
NOTE: When
increasing to a wide, flat pattern, you may
have to increase the supply of fluid to the gun to
maintain the same amount of coverage over a
large
area.
When all adjustments of atomizing air , fluid pressure, and
fan pattern are made, the Power Supply can be turned on
and operation can begin. (The spray pattern may need to
be adjusted slightly after the Power Supply is turned on.)
Flush the Spray Gun
WARNING
To
reduce the risk of fire or explosion and serious
bodily injury , the Power Supply MUST be turned
OFF before flushing.
1. Turn
of f the Power Supply (K). Follow the Pressure
Relief
Procedure W arning on page 9.
3. Disconnect and plug the fluid line.
4. Connect the solvent supply to the gun.
5. Run solvent through the gun.
6. Disconnect the solvent supply .
7. Reconnect the fluid supply line.
8. T urn on the fluid and air supplies.
9. T rigger the gun until it is clean of solvent.


MAINTENANCE
Daily Care and Cleaning
For Y our Safety , always follow the Pressure Relief Pro -
cedure on page 9 when shutting off the system, when
you
stop spraying and before checking, servicing, install -
ing,
cleaning or changing any part in the system.
1. Clean the fluid and air line filters daily .
2. Clean the outside of the gun daily with a soft cloth,
dampened
in a compatible solvent.
3. Clean the air cap and fluid nozzle daily, minimum.
Some applications require more frequent cleaning.
Replace the fluid nozzle and air cap if they are
damaged. See Clean the Air Cap and Fluid
Nozzle,
below .
4. Check the electrode (56). Straighten it if bent, and re -
place it if broken or damaged. See page 16 for re-
placing
the electrode.
5. Check all of the work hangers for build–up of
material;
clean them, if necessary .
CAUTION
Do
not use metal tools to clean the air cap holes as
this may scratch them, and make sure the elec-
trode
wire is not damaged. Scratches in the air cap
holes or a damaged electrode wire can distort the
spray pattern.
Do not use any cleaning method which may al -
low
solvent into the gun air passages. Clogged
air passages cause poor atomization and exces-
sive current demands. Point the gun down while
cleaning to prevent dirty solvent from running back
into the air passages. NEVER IMMERSE THE
GUN
IN SOL VENT.
Clean all parts with a non–conductive solvent,
compatible with the fluid being sprayed.
Conductive solvents can cause the gun to
malfunction.
Clean the Air Cap and Fluid Nozzle
Equipment needed:
Soft bristle brush (supplied).
Fluid nozzle wrench (supplied).
Solvent compatible with fluid being sprayed.
Procedure:
1. Turn off the Power Supply. Follow the Pressure
Relief
Procedure W arning on page 9.
2. Remove the retaining nut (47) and air cap (17). See
Fig 4.
3. Squeeze the gun trigger and remove the fluid nozzle
(19) with the fluid nozzle wrench (77b) supplied.
Make
sure the front of the gun is held down. See Fig
4.
4. Use the soft bristle brush (77a), supplied, and sol-
vent
to clean the air cap, fluid nozzle, and front part of
the gun.
5. Squeeze the gun trigger and screw the fluid nozzle
back
into the gun finger tight. T orque the fluid nozzle
to 10–12 in–lb (1.1–1.4 N.m) (about 1/4 of a turn) with
the wrench (77b) supplied.
6. Replace the retaining nut and air cap carefully to
avoid bending the electrode wire (56). Tighten the
retaining nut so it is snug, allowing the air cap to turn
with resistance. If it is too tight, the spray pattern will
be distorted.
Fig 4
KEY
17 Air Cap
19 Fluid Nozzle
47 Retaining Nut
56 Electrode
77b Wrench
77b
47
17
56
19

12 307-860
SPRAY PA TTERN TROUBLESHOOTING CHART
WARNING
Installing
and servicing this equipment requires access to parts which may cause electric shock or other serious
bodily injury if the work is not performed properly . Do not install or service this equipment unless you are trained and
qualified.
To reduce the risk of serious bodily injury, including splashing fluid or solvent in the eyes or on the skin, always
follow the Pressure Relief Procedure on page 9 before checking, adjusting, cleaning or repairing the gun or any
part of the system. Disconnect the fluid hose from the gun.
NOTE: Check all possible remedies in the T roubleshooting Charts before disassembling the gun.
Insuf ficient fluid supply . Adjust fluid regulator or fill fluid tank.
Dry or worn fluid needle packing Lubricate or replace packing,
or loose packing nut permits air tighten packing nut.
to get into fluid passage.
Loose fluid nozzle or damaged T ighten or replace fluid nozzle.
fluid nozzle taper seat.
Dirt between fluid nozzle, taper Clean.
seat and body .
Loose or cracked coupler at T ighten or repair .
fluid inlet.
Loose fluid tube in cup or tank. Tighten.
Fluid build–up on air cap; partially Clean with soft implement or
clogged horn holes. Full air pres– submerge in suitable solvent and
sure from clean horn hole forces wipe clean.
fan pattern toward clogged end.
Damaged fluid nozzle or air Replace damaged part.
cap holes.
Fluid build–up on the perimeter Remove obstruction. Never use
of fluid nozzle orifice, or partially wire or hard instruments.
clogged fluid nozzle orifice
T oo high atomization air pressure. Reduce air pressure or adjust air
adjusting valve.
Fluid too thin. Regulate fluid viscosity .
Not enough fluid pressure Increase fluid pressure.
Low atomization air pressure Raise air pressure.
Fluid too thick Regulate fluid viscosity .
T
oo much fluid. Reduce fluid flow . Reduce fluid
pressure on pressure feed guns
and/or adjust fluid adjusting screw
until proper pattern is obtained.
Last coat of fluid applied too wet. Apply drier finish with multiple strokes.
T oo much air pressure. Use least air pressure necessary .
Insuf
ficient air pressure. Increase air pressure.
Non–uniform spray pattern. Clean or replace air cap.
PROBLEM: CAUSE SOLUTION
IMPROPER SPRA Y
PATTERN
Fluttering or spitting
spray
Streaks
NOTE: Some improper patterns are caused by the improper balance between air and fluid.

13307-860
GUN OPERA TION TROUBLESHOOTING CHART
Misalignment between air cap Remove and clean air cap and fluid
and fluid nozzle. nozzle as described in Maintenance
Section under Clean the Air Cap and
Fluid Nozzle , then reinstall them.
PROBLEM CAUSE SOLUTION
Loose packing nut (27). Tighten.
W
orn needle packing (6). Replace needle packing.
Air leakage from front of
gun.
Fluid leakage from front
of gun.
Air valve not seating properly . Clean, service.
Air stem packing too tight. Loosen packing.
T oo much air pressure. Reduce,use least air pressure
needed for good results.
Fluid thinned too much. Properly thin fluid.
Electrode (56) worn or damaged. Replace electrode.
W orn fluid seat. Replace fluid nozzle (19) and/or
electrode (56).
Fluid packing (6) too tight. Lubricate packing and adjust packing
nut (27).
Loose fluid nozzle (19). T ighten fluid nozzle.
Fluid adjusting screw (54) not Adjust screw .
set correctly .
Excessive spray fog.
Leakage from fluid pack -
ing nut.
Insuf ficient air pressure. Increase, use least air pressure
needed for good results.
Fluid poorly mixed or filtered. Remix or refilter fluid.
Improper thinner being used. Use proper thinner .
“Orange Peel” finish.
Fluid low . Check, add if necessary .
Damaged air cap (17). Replace air cap.
Dirty or clogged fluid nozzle (19). Clean fluid nozzle.
Damaged fluid nozzle (19). Check, replace fluid nozzle.
No fluid sprays from gun.
Exhaust air flow insufficient Check for proper CFM, check
or not directed properly . baf fles and direction of air flow .
Equipment closer to ionizing Mount gun closer to target.
nozzle than object being sprayed.
Equipment covered with
fluid.
Equipment covered with
fluid.

14 307-860
ELECTRICAL TROUBLESHOOTING CHART
Parts poorly grounded. Clean hangers, check for proper
ground on conveyer or track.
High exhaust velocity . Reduce within code limits.
High fluid pressure. Reduce pressure.
Fluid viscosity . Check supplier for proper fluid for
electrostatic spray .
Low or no electrostatic voltage. See below .
Faulty gun resistance. Check; resistance should be 250
megohms + 20 from the end of the
gun electrode (56) to the end
of the High V oltage Cable, where it
connects to the Power Supply . If
resistance is lower , check resistance
of resistor (12) and electrode (56).
Improper distance between gun Adjust spraying distance to
and workpiece. 8–12 in. (203–305 mm).
T oo high atomizing air pressure. Reduce air pressure.
T oo low fluid resistivity . Check fluid resistivity with paint
meter and probe (refer to Instruction
Manual 307–263).
Faulty Power Supply resistance. Check Power Supply resistance. See
instruction manual included with
power supply .
Faulty needle electrode assembly . Replace needle electrode assembly .
PROBLEM CAUSE SOLUTION
Poor wrap–around.
Power Supply is of f. Line Power Switch is OFF , should be
turned ON.
Fuse on inside of Power Supply Replace fuse.
is blown.
Power line voltage is incorrect. Adjust for correct voltage.
Low or no electrostatic
wrap.
Low or no electrostatic
wrap. (Spraying voltage
light comes on, then goes
off).
Gun held too close to part being Increase distance between part
painted. and gun.
Fluid is too conductive. Lower conductivity of fluid or adjust
T ime Delay Relay setting on Power
Supply . See PS7500M Power Supply
Manual 307–859.
Electrical short in the High Replace the High V oltage Cable.
V oltage Cable.
Electrical short in gun. T ake gun apart and visually check the
resistor housing (40), resistor well
and needle well in the gun barrel (36)
for dirt and/or damage. Clean and
replace parts as required.
Faulty Power Supply . See instruction manual included with
Power Supply .
Continued on next page.

15307-860
ELECTRICAL TROUBLESHOOTING CHART
PROBLEM CAUSE SOLUTION
Faulty resistor stud (71). Replace the resistor stud.
Resistor (12) not making a good See Resistor Assembly Replace–
connection with contact inside of ment , in the Service Section.
gun body .
High V oltage Cable not making Replace conductive spring (58c)
good contact with resistor (58a). as required.
Cable insulation punctured. Replace cable.
Spring at transformer end of Stretch spring.
cable not making good contact.
Electrical short in High V oltage Replace the High V oltage Cable.
Cable.
Electrical short in gun. T ake gun apart and visually check the
resistor housing (58b), resistor well
and needle well in the gun barrel (36)
for dirt and/or damage. Clean and
replace parts as required.
Faulty Power Supply . See instruction manual included with
Power Supply .
Low or no electrostatic
wrap. (Spraying voltage
light is on all the time).
Air flow switch in Power Supply Check switch, replace if faulty .
not working or sluggish return.
Spraying voltage stays
on when gun trigger is
released.
Faulty Power Supply . See instruction manual included with
Power Supply .
Air flow switch is stuck or Replace or repair air flow switch.
sluggish.
Low or no electrostatic
wrap. (Spraying voltage
light does not come on).
W ork piece not properly Clean work piece hangers. Check for
grounded. proper ground on conveyor or track.
Operator not properly grounded Be sure floor is properly grounded.
or is in contact with ungrounded W ear shoes with non–insulating
object. soles. Be sure operator is not in
contact with or carrying any metallic
items which could build up electrical
charge. If a glove is worn, modify it
as shown on page 9. Be sure high
voltage cable is undamaged and
power supply is properly grounded.
Gun not properly grounded. See Check the Electrical Grounding
in the Installation Section.
Operator gets mild
shock when touching
work piece.

16 307-860
SERVICE
Gun Disassembly
WARNING
Installing and servicing this equipment requires
access
to parts which may cause electric shock or
other serious bodily injury if the work is not per-
formed properly. Do not install or service this
equipment unless you are trained and qualified.
Follow the Pressure Relief Procedure, page 9,
before
servicing the gun or any part of the system.
Disconnect the fluid hose from the gun.
NOTE: Check all possible remedies in the
Troubleshooting
Charts before disassembling
the gun.
CAUTION
If the plastic parts of the gun must be held se-
curely, ALWAYS clamp them in padded vice jaws
to
prevent damage to the parts.
ALWAYS lubricate o–rings and seals with petro-
leum
jelly .
ALWAYS
remove gun from worksite for service or
repair. Service or repair area must be clean.
Flush the gun as described under Flush the Spray Gun
in the Operation Section. Follow the Pressure Relief
Procedure Warning on page 9. Disconnect the air and
fluid
line from the gun.
Disconnect the High Voltage Cable from the gun and
cover the cable to prevent contamination. The High
Voltage Cable can stay at the worksite when you service
the gun.
NOTE: Parts included with a repair kit are marked with
an
asterisk, for example, (77d*).
Electrode Replacement
Remove the air cap (17) and fluid nozzle (19) as de-
scribed
in the Maintenance Section under Clean the Air
Cap and Fluid Nozzle.
Remove the electrode (56*) with the wrench (77d*) sup -
plied.
See Fig 5. Hold the needle shaft assembly (55) nut
with a small wrench if the needle turns.
Install the new electrode assembly with the wrench. Do
not
over tighten.
CAUTION
To avoid damaging the plastic threads, be very
careful when installing the electrode.
Install the air cap and fluid nozzle as described in the
Maintenance Section under Clean the Air Cap and
Fluid Nozzle .
The barrel retaining ring (26) and the retaining nut (48) do
not have to be removed. If they must be replaced, lift one
end of the retaining ring out of its groove and spiral it of f
the
end of the barrel. Then remove the retaining nut. Spi -
ral
the new retaining ring back over the barrel.
Fig 5
KEY
77d Wrench
*77d

307-860 17
SERVICE
Barrel Removal
Remove the three nuts (81) and screws (80), then re-
move
the shroud (79). See Fig 6.
Disconnect the fluid hose nut (67) and collar (68) from the
fitting (39). See Fig 7.
Pull the tube (31) out of the fitting (39).
NOTE: If the tube (31) needs to be replaced, be sure to
wrap the new tube around the barrel (36) three
times.
Refer to Fig 6.
Remove the trigger by removing the screws (33) and
spacers (61) from the gun.
Loosen the retaining nut (48), using the wrench (77b)
supplied.
Hold
the gun handle (57) with one hand and pull straight
up to remove the gun barrel (36). See Fig 8.
The barrel may slide off with heavy resistance. Pull the
barrel
straight up to avoid damaging the resistor housing
(58b).
NOTE: The gasket (34) should be left in the gun handle if
it is not being replaced. See the Parts Drawing
on
page 22 for the gasket location.
Fig 6
KEY
79 Shroud
31 Fluid
T ube
36
Gun Barrel
80 Screw
81 Nut
79
81
80
36 31
W rap around
barrel 3 times
Fig 7
KEY
31 Fluid T ube
33 Screw
39 Adapter
48
Retaining Nut
61 Spacer
67
Fluid Hose Nut
68 Collar
77b Wrench
31
33,
61
39
77b
67, 68
48
Fig 8
KEY
26 Retaining Ring
36 Gun Barrel
48 Retaining Nut
57 Gun Handle
57
36
26,
48

18 307-860
SERVICE
Fluid Packing Removal
Remove the electrode resistor as described in Electrode
Replacement.
Remove
the barrel as described in Barrel Removal .
Carefully remove the needle shaft assembly (55) from
the
rear of the barrel (36). See Fig 10.
Remove the packing nut (27) at the rear of the barrel, us -
ing
the wrench (77c) supplied.
NOTE: The nut (55a) is secured with Loctite ) to the nee -
dle shaft assembly (55) and should not be re-
moved.
If the nut is removed, it will have to be re -
assembled to the needle shaft assembly with
Loctite
No. 271 to the proper dimension. See Fig
9 for the correct length.
Slide the insulator (32) and support (23) off the needle
shaft.
Place barrel on a table top in a vertical position with the
back of the barrel touching the table top. Insert the rod
(77e),
supplied, in the front of the barrel and gently tap out
the needle packing (6*) and support (23). Check all the
parts
for wear or damage, replace them if necessary .
CAUTION
Use extreme care when handling the packing (6)
because
it is very brittle. Y ou may want to keep ex -
tra
packings on hand.
Clean all parts in non–conductive solvent
compatible
with the fluid being used, such as xylol
or mineral spirits. Use of conductive solvents can
cause the gun to malfunction.
Fluid Packing Replacement
Slide the packing nut (27) onto the fluid needle shaft (55).
Then slide the insulator (32) onto the needle shaft. The
holes in the one end of the insulator (32) must face to-
ward
the electrode end of the fluid needle shaft (55), as
shown in Fig 10.
Place the packing (6*) between the two supports (23),
with the beveled side of the supports facing toward the
packing. Slide the packing, with the supports, onto the
fluid
needle shaft (55).
Place the spring (13) over the nut (55a). Slide the barrel
over the resistor housing. With one hand, push the barrel
up against the front part of the gun handle. Using the
other hand, start and tighten the retaining nut (48). See
Fig 1 1.
Reassemble the needle electrode (56*), fluid nozzle (19)
and air cap (17) as described in the Maintenance Section
under Clean the Air Cap and Fluid Nozzle .
1.76 in.
(44 mm + 1 )
Fig 9
KEY
55 Needle Shaft Assy
55a Adjusting Nut
55
6.1 in. (155.3 mm)
55a
0
13
Fig 10
KEY
6Needle Packing
13 Spring
23 Support
27
Packing Nut
32 Insulator
36
Gun Barrel
55 Needle Shaft Assy
55a Nut
Beveled Side
Faces Packing (6)
55a
36

 
SERVICE
Fig 11
KEY
48 Retaining Nut
48
Resistor Assembly Replacement
Remove the trigger by removing the two screws (33) and
spacers (61). See Fig 12. Remove the gun barrel as de -
scribed in Barrel Removal. Remove the gasket (34)
from
the gun barrel (36) and replace if damaged.
Slide the hook (50) forward and out of the gun channel.
Pull
the resistor housing (58b) up and forward to remove
it from the gun handle (57) chamber . Remove the spring
(11) from the end of the resistor .
CAUTION
Clean all parts in non–conductive solvent
compatible
with the fluid being used, such as xylol
or mineral spirits. Use of conductive solvents can
cause the gun to malfunction. Do not submerge
the
resistor in solvent.
Check all parts for wear or damage, replace them if
necessary.
Place the new o–rings (69, 10*) over the new resistor
housing
(58b) and lubricate them with petroleum jelly .
CAUTION
All o–rings and conductive springs must be in
place
or the gun will malfunction.
Insert the resistor housing (58b) down through the top of
the gun. Slide the hook (50) into place.
Replace the barrel assembly by reversing the procedure
described in Barrel Removal .
Fig 12
KEY
10 O–Ring
11 Spring
33 Screws
50 Hook
57 Gun
Handle
58 Resistor Assy.
58a Resistor
58b
Resistor Housing
58c Spring
61 Spacers
69 O–Ring
58b
58a
58c
Spring inside
resistor housing
57

 
SERVICE
Fan Air Valve Replacement
Place a wrench on the valve housing (42) flats and
remove
the housing from the handle. See Fig 13.
Remove the retaining ring (14). Remove the air adjusting
screw (41) from the valve housing (42), turning it
counterclockwise .
Clean all parts, inspect for wear or damage, and replace if
necessary.
Lubricate the o–ring and the threads of the air adjusting
screw (41) with petroleum jelly .
Install the adjusting screw (41) into the valve housing
(42),
turning it clockwise, and secure it with the retaining
ring (14) .
Back the adjusting screw out of the valve housing (42)
until
it bottoms out against the retaining ring (14).
Apply Loctite ) pipe sealant to the threads of the housing
(42). Install the housing (42) into the gun handle, torquing
it to 14–20 ft/lb (20–27 N.m).
Air V alve Replacement
Using a screwdriver, remove the retainer (29), spring
(62),
and air valve stem (59) from the gun handle. See Fig
14. Replace parts as needed and install them back into
the
gun handle.
CAUTION
Clean
all parts in non–conductive solvent compatible
with the fluid being used, such as xylol or mineral
spirits. Use of conductive solvents can cause the
gun
to malfunction.
Install the new packing (18*) and guide (30) into the front
of the gun handle.
Tighten the guide (30) into the gun handle. Squeeze the
trigger and adjust it until there is no movement, then back
it of f until it moves freely .
KEY
14 Retaining Ring
41 Air Adjusting Screw Assy
42 V alve Housing
KEY
18 Packing
29 Retainer
30 Guide
59
Air V alve Stem
62 Spring
Apply Loctite
T orque to 14–20 ft/lb
(20–27 N.m)
14
41
29
62
59
*18
30
Fig 14 Fig 13
42