Roberts 61-251 User manual

OWNER’S MANUAL
308–021 Rev D
Supersedes C
CARPET ADHESIVE SPRAYER
1/4 Gallon Per Minute, 120 VAC, 60 Hz
3000 psi (210 bar) Maximum Working Pressure
MODEL 61–251
For use with non–flammable,
water–base adhesive
Part No. 231–109, Series C
Complete Sprayer with hose and gun.
U.S. Patent No. 4,616,982
U.K. Patent No. 2,165,591
Other Foreign Patents Pending
ROBERTS CONSOLIDATED INDUSTRIES,
INC.
P
.O. BOX 1250/600 N. Baldwin Park Blvd.
City of Industry , California 91749
This manual contains important
warnings and information.
READ AND RETAIN FOR REFERENCE
Liquids can be injected into the body by high pressure airless
spray
or leaks – especially hose leaks.
Keep body clear of the nozzle. Never stop leaks with any part of the
body. Drain all pressure before removing parts. A void accidental
triggering of gun by always setting safety latch when not spraying.
Never spray without a tip guard.
In case of accidental skin injection, seek immediate “Surgical
Treatment”.
Failure
to follow this warning can result in amputation or serious
injury.
FIRE AND
EXPLOSION HAZARD
SKIN INJECTION
HAZARD
READ AND UNDERSTAND ALL LABELS AND INSTRUCTION MANUALS BEFORE USE
Spray painting, flushing or cleaning equipment with flammable liq -
uids
in confined areas can result in fire or explosion.
Use outdoors or in extremely well ventilated areas. Ground equip -
ment,
hoses, containers and objects being sprayed.
Avoid all ignition sources such as static electricity from plastic
drop
cloths, open flames such as pilot lights, hot objects such as
cigarettes, arcs from connecting or disconnecting power cords or
turning light switches on and off.
Failure to follow this warning can result in death or serious injury .
NOTE: This is an example of the DANGER label on your sprayer . This label
is available in other languages, free of charge. See page 15 to order .

 
WARNINGS
High Pressure Spray Can Cause Serious Injury . For Professional Use Only.
Observe All W arnings. Read and understand all instruction manuals before operating equipment.
FLUID INJECTION HAZARD
General Safety
This equipment generates very high fluid pressure. Spray from
the gun, leaks or ruptured components can inject fluid through
your skin and into your body , and cause extremely serious
injury, including the need for amputation. Also, fluid injected or
splashed into the eyes or on the skin can cause damage.
Never point the spray gun at any one or at any part of the body .
Never put your hand or fingers over the spray tip. Never try to
“blow back” adhesive; this is not an air spray system.
Always have the tip guard in place on the spray gun when spray -
ing.
Always follow the Pressure Relief Procedure, below, before
cleaning or removing the spray tip or servicing any system
equipment.
NEVER
try to stop or deflect leaks with your hand or body .
Be
sure equipment safety devices are operating properly before
each use.
Medical Alert––Airless Spray W ounds
If any fluid appears to penetrate your skin, get emergency
medical care at once. Do not treat as a simple cut . T ell the
doctor exactly what fluid was injected.
Note to Physician : Injection in the skin is a traumatic injury .
It is important to treat the injury surgically as soon as possible.
Do not delay treatment to research toxicity . Toxicity is a
concern with some exotic coatings injected directly into the
blood stream. Consultation with a plastic surgeon or re-
constructive
hand surgeon may be advisable .
Spray Gun Safety Devices
Be sure all gun safety devices are operating properly before
each use. Do not remove or modify any part of the gun; this can
cause a malfunction and result in serious injury .
Safety Lever
Whenever you stop spraying, even for a moment, always lock
the gun safety lever, making the gun inoperative. Failure to set
the safety lever can result in accidental triggering. See the illus -
tration
below .
Safety lever in
unlocked or
spraying
position.
Safety lever in
the locked or
inoperative
position.
TRIGGER
V
iew from front of gun

Diffuser
The gun diffuser breaks up spray and reduces the risk of fluid
injection
when the tip is not installed. Check dif fuser operation
regularly . Follow the Pressure Relief Procedure , below , then
remove the spray tip. Aim the gun into a metal pail, holding the
gun firmly to the pail. Using the lowest possible pressure, trigger
the gun. If the fluid emitted is not diffused into an irregular
stream, replace the dif fuser immediately .
T ip Guard
Always have the tip guard in place on the spray gun while spray -
ing. The tip guard alerts you to the fluid injection hazard and
helps
reduce, but does not prevent, the risk of accidentally plac -
ing your fingers or any part of your body close to the spray tip.
Trigger Guard
Always have the trigger guard in place on the gun when spray -
ing to reduce the risk of accidentally triggering the gun if it is
dropped
or bumped.
Spray T ip Safety
Use extreme caution when cleaning or changing spray tips. If
the
spray tip clogs while spraying, lock the gun safety lever im -
mediately. Always follow the Pressure Relief Procedure, be -
low
, and then remove the spray tip to clean it.
Never wipe of f build–up around the spray tip until the pressure
is fully relieves and the gun safety is locked.
Pressure Relief Procedure
To reduce the risk of serious injury , including fluid injection,
splashing fluid or solvent in the eyes or on the skin, or injury from
moving parts or electric shock, always follow this procedure
whenever you shut of f the sprayer , when checking or servicing
any part of the spray system, when installing, cleaning or chang -
ing
spray tips, and whenever you stop spraying.
1. Shut of f the sprayer and unplug it.
2. Hold a metal part of the gun firmly to the side of a grounded
metal pail, and trigger the gun into the adhesive pail to relieve
pressure.
3.
Lock the gun safety lever .
4. Turn
the bypass valve ONE turn counterclockwise to drain
adhesive back into the pail.
If you suspect that the spray tip or hose is completely clogged,
or that pressure has not been fully relieved after following the
steps above, very slowly loosen the part to relieve pressure
gradually,
then loosen completely . Now clear the tip or hose.

 
EQUIPMENT MISUSE HAZARD
General Safety
Misuse of the spray equipment or accessories, such as over
pressurizing, modifying parts, using incompatible chemicals
and
fluids, or using worn or damaged parts, can cause them to
rupture and result in fluid injection, splashing in the eyes or the
skin, or other injury, or fire, explosion or property damage.
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 damaged parts immediately .
Always
wear protective eyewear , gloves, clothing and respira -
tor
as recommended by the fluid and solvent manufacturer .
System Pressure
This sprayer can develop 3000 psi (210 bar) Maximum Working
Pressure. Be sure all spray equipment and accessories used
are rated to withstand the this pressure. Do not exceed the
maximum working pressure of any component or accessory
used
in the system.
Fluid and Solvent Compatibility
All chemicals used in the sprayer are chemically compatible
with
the wetted parts shown in the T echnical Data on the back
cover. Always read the chemical manufacturer’s literature be-
fore
using them in this sprayer .
Hazard of Using Fluids Containing Halogenated
Hydrocarbons
Never use 1,1, 1–trichloroethane, methylene chloride, other
halogenated hydrocarbon solvents or fluids containing such
solvents
in this equipment. Such use could result in a chemical
reaction, with the possibility of explosion, which could cause
death,
serious injury and/or substantial property damage.
Consult your fluid suppliers to ensure that the fluids being used
are compatible with aluminum and zinc parts.
FIRE OR EXPLOSION HAZARD
Static electricity is created by the flow of fluid through the pump
and hose. If every part of the spray equipment is not properly
grounded, sparking may occur , and the system may become
hazardous. Sparking may also occur when plugging in or un-
plugging a power supply cord or using a gasoline engine.
Sparks can ignite fumes from solvents and the fluid being
sprayed, dust particles and other flammable substances,
whether you are spraying indoors or outdoors, and can cause
a fire or explosion and serious injury and property damage.
If you experience any static sparking or even a slight shock
while using this equipment, stop spraying immediately .
Check the entire system for proper grounding. Do not use the
system again until the problem has been identified and cor-
rected.
Grounding
To reduce the risk of static sparking, ground the sprayer and all
other spray equipment used or located in the spray area. Check
your local electrical code for detailed grounding instructions for
your area and type of equipment. Be sure to ground all of this
spray
equipment:
1. Sprayer: plug the power supply cord, or extension cord, each
equipped with an undamaged three-prong plug, into a prop -
erly grounded outlet. Do not use an adapter. All extensions
cords
must have three wires and be rated for 15 amps.
2. Fluid hoses: use only grounded hoses with a maximum f
500 ft (150 m) combined hose length to ensure grounding
continuity.
See Hose Grounding Continuity below.
3.
Spray gun: obtain grounding through connection to a prop-
erly
grounded fluid hose and sprayer .
4.
Object being sprayed: according to local code.
5. Fluid supply container: according to local code.
6. All solvent pails used when flushing, according to local code.
Use only metal pails, which are conductive. Do not place the
pail on a non–conductive surface, such as paper or card-
board,
which interrupts the grounding continuity .
7.
To maintain grounding continuity when flushing or relieving
pressure
, always hold a metal part of the gun firmly to the side
of a grounded metal pail, then trigger the gun.
Flushing Safety
Reduce the risk of fluid injection injury , static sparking, or
splashing
by following the flushing procedure given on page 7
of this manual. Follow the Pressure Relief Procedure on page
2, and remove the spray tip before flushing. Hold a metal part
of
the gun firmly to the side of a grounded metal pail and use the
lowest possible fluid pressure during flushing.
HOSE SAFETY
High pressure fluid in the hoses can be very dangerous. If the
hose develops a leak, split or rupture due to any kind of wear,
damage or misuse, the high pressure spray emitted from it can
cause a fluid injection injury or other serious injury or property
damage.
All fluid hoses must have strain reliefs on both ends!
The
strain reliefs help protect the hose from kinks or bends at or
close
to the coupling which can result in hose rupture.
Tighten all fluid connections securely before each use. High
pressure
fluid can dislodge a loose coupling or allow high pres -
sure spray to be emitted from the coupling.
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 ex -
ist, replace the hose immediately. Do noT try to recouple high
pressure hose or mend it with tape or any other device. A re-
paired
hose cannot contain the high pressure fluid.
Handle and route hoses carefully . Do not pull on hoses to move
equipment. Keep hoses clear of moving parts and hot surfaces
of the pump and gas engine. Do not use fluids or solvents which
are not compatible with the inner tube and cover of the hose. Do
not expose Graco hoses to temperatures above 180  F (82  C)
or below –40  F (–40  C).
Hose Grounding Continuity
Proper hose grounding continuity is essential to maintaining a
grounded spray system. Check the electrical resistance of your
fluid hoses at least once a week. If your hose does not have a
tag on it which specifies the maximum electrical resistance,
contact
the hose supplier or manufacturer for the maximum re -
sistance limits. Use a resistance meter in the appropriate range
for your hose to check the resistance. If the resistance exceeds
the recommended limits, replace it immediately . An un-
grounded
or poorly grounded hose can make your system haz -
ardous.
Also read FIRE OR EXPLOSION HAZARD, above.
IMPORTANT
United States Government safety standards have been adopted under the Occupational Safety and Health Act. These standards –
particularly the General Standards, Part 1910, and the Construction Standards, Part 1926 – should be consulted.

 
Setup
1. Prepare the adhesive.
This is probably the most important step
toward trouble-free spraying!
Prepare the adhesive according to the manufactur -
er’
s recommendations. Remove any skin that may
have formed on the top of the coating. If neces -
sary
, thin the coating.
2. Install a spray tip and the tip guard on the spray
gun.
Place the tip washer between the gun outlet and
the extension tube.
3. Screw the gun tightly on the hose. Connect the
other
end of the hose to the 1/4 npsm(m) outlet nipple
of the sprayer .
4.
Check the hydraulic oil level. Unscrew the fill cap
(5). The oil should be 1 inch (25 mm) from the top of
the plate. If it is not, fill as necessary with lightweight
hydraulic oil; use only Graco Hydraulic Oil, Part No.
218–797. Install the fill cap. See Fig. 1.
5. Check the electrical service. It must be 120 VAC,
60
Hz, 15 Amp (minimum). Be sure the electrical out -
let
is properly grounded.
Y ou can use up to 100 foot (30 m) of 3 wire, 14
gauge (minimum) extension cord. Longer exten -
sion cords may af fect the sprayer performance.
Use more spray hose, not longer extension cords.
Do not remove the third (grounding) prong of the
plug, and do not use an adapter .
6. Plug in the sprayer . First be sure the ON/OFF
switch (11) is OFF and the pressure control (4) is
turned
fully counterclockwise . Plug the sprayer into
a grounded outlet that is at least 20 foot (6 m) away
from the spray area to reduce the chance of a spark
igniting spray vapors or dust particles.
Fig. 1
1 inch
(25 mm)
0269
5
Fig. 2
0270
11
4
1
2
Decrease
pressure (counterclockwise).
Increase pressure (clockwise).
2
1

 
Startup
CAUTION
The wallet sized warning card provided with the gun
should be kept with the operator at all times. The card
contains important information on reducing the risk of
a fluid injection injury , and treatment information
should an injection injury occur. Additional copies of
this
card are available at no cost.
CAUTION
Never start the electric motor with the inlet valve
removed,
as it will severely damage the diaphragm.
NOTE: If the sprayer has been started before, be sure
the pressure has been relieved or the sprayer will not
start.
1. Open the bypass valve (66) ONE turn counter-
clockwise.
Do not place the pump intake in the pail
yet. See Fig. 3.
2. Turn the pressure control fully (4) clockwise to in-
crease
pressure. See Fig. 3.
3. Remove the inlet strainer (27) and place your hand
over the inlet valve. Start the sprayer and confirm
that
it is drawing a vacuum.
NOTE: If the inlet valve (26) is not drawing a vacuum,
turn
the sprayer OFF . T urn the sprayer over . Press down
on the stem (A) inside the inlet valve lightly with a small
screwdriver, and pour about a teaspoon of mineral spirits
or solvent into the valve. See Fig. 4. Release the valve
and
turn the sprayer upright. With the pressure turned up,
turn on the sprayer . This should free any sticking parts in
the pump. Now check again for a vacuum. Shut of f the
sprayer
and install the inlet strainer (27).
4. Place the adhesive pump assembly into a properly
prepared
5 gallon pail of adhesive.
5. Turn the sprayer ON and allow the adhesive to circu -
late
through the bypass valve (4) for one or two min -
utes.
NOTE: If the adhesive does not circulate back into the
pail, turn down the pressure and turn the motor on and
off
several times to help prime the sprayer .
6. Turn the bypass valve (66) clockwise (finger tight)
to
close it; this allows the pump to build up pressure.
7. Release the trigger safety lever . T rigger the gun onto
a piece of paper to check the spray pattern. The
spray
pattern should be 12 to 18 inches wide with the
tip held 12 inches from the surface. Start at the low -
est pressure setting and then increase the pressure
until you get the recommended spray fan width. T oo
much pressure creates an unacceptable “fogging”
pattern.
8. Whenever you stop spraying, always set the trigger
safety lever to prevent accidentally triggering the
gun.
9. Whenever you stop spraying for more than a mo-
ment,
and when the sprayer is unattended, shut it of f
and
follow the Pressure Relief Procedure on page
2.
10. If the tip clogs, engage the trigger safety lever, shut
off and unplug the sprayer , and open the bypass
valve
one turn counterclockwise . Disassemble the
tip in the reverse order of assembly (see manual
307–821). Thoroughly clean all parts in a warm,
soapy water and inspect for wear or damage. Re-
place parts as needed and reassemble. Be sure to
use
a new seal and gasket when changing tips.
11. Important maintenance procedures are given on
pages
6 and 7.
Fig. 3
Fig. 4
0271
0272
27
66
4
1
3
4
2
Decrease
pressure
(counterclockwise).
Increase pressure (clockwise).
Open (counterclockwise).
Close (clockwise).
1
3
4
2
22
26
A

 
Maintenance
CAUTION
Thorough flushing and proper maintenance are
essential to keep the sprayer working properly
and
avoid costly damage to the sprayer or the ob -
ject being sprayed.
Diaphragm Failure: Always replace the diaphragm
after
every 500 hours of operation (once every 4 to 6
months). The diaphragm weakens with use. If it rup -
tures,
hydraulic oil and adhesive may mix, damaging
the sprayer and/or the surface of the object being
sprayed
may be damaged.
Follow the Maintenance Intervals outlined below .
CAUTION
Failure to properly tighten the inlet valve and screws
at the intervals indicated will result in oil leaking from
the hydraulic system into the adhesive, and can
cause
costly damage to the sprayer .
Maintenance Intervals
Flushing Immediately after each use.
Lubricate the intake valve. Immediately after each use.
Tighten the fluid pump
screws
and the inlet valve.
1. After the first 3 to 5 hours of
operation.
2. After the next 3 to 5 hours
of
operation.
3. Each 25 hours thereafter
(about weekly).
Check or change the hydrau -
lic
oil.
1. Check the oil after each
use
of the sprayer .
2. Change the oil after the first
20 hours of operation.
3. Change the oil each 50
hours thereafter (about twice
monthly).
Replace the diaphragm. After every 500 gallons of
fluid
sprayed (4 to 6 months).
Tighten the Fluid Pump Screws and Inlet V alve
See Fig. 5.
1. Follow the Pressure Relief Procedure on page 1 1.
2. Torque the four screws (25) on the fluid pump to
170–200
in–lb (19–23 N.m).
3. Torque the inlet valve (26) to 320–360 in–lb (36–41
N.m).
Fig. 5
0273
1
3
2
Lubricate
the threads.
T orque to 170–200 in–lb (19–23 N.m)
T orque to 320–360 in–lb (36–41 N.m)
22
26
25
12
1 3
Lubricate the Inlet V alve. See Fig. 6.
1. Follow the Pressure Relief Procedure on page 1 1.
Remove
the inlet screen.
2. Turn the sprayer over . Press down lightly on the stem
of the inlet valve with a small screwdriver . Pour about
a teaspoon of mineral spirits or solvent into the valve,
then remove the screwdriver .
3. Set the sprayer upright. Increase the pressure con-
trol
setting half way . T urn on the sprayer for a few se -
conds,
then turn it OFF .
4. Now tighten the fluid pump screws and the inlet
valve.
Fig. 6
0272
22
26
A

 
Check and/or Change the Hydraulic Oil
See Fig. 7.
1. Follow the Pressure Relief Procedure on page 2.
2. Remove the fill cap. The oil should be 1 inch (25 mm)
from the top of the plate. If it is lower , add oil as nec -
essary.
use only Graco lightweight hydraulic oil, part
no. 218–797. Reinstall the fill cap, hand tight, if you
are
not going to change the oil.
3. To change the oil, turn the sprayer over and drain the
oil through the fill cap hole.
CAUTION
Whenever you remove the fill cap, be very careful not
to let any dirt, adhesive particles, or other contami-
nants get into the hydraulic system. Contaminants
can
cause damage to the hydraulic system.
4. Fill the hydraulic pump housing with 16.5 ounces (55
ml) of Graco lightweight hydraulic oil. Reinstall the fill
cap.
5. Plug in the sprayer . Turn the pressure control fully
counterclockwise (no pressure). T urn on the
sprayer
and let it run for two minutes to fill the hydrau -
lic system. Increase the pressure to maximum and
turn
the sprayer on and of f four times to help rid the
hydraulic system of air .
Flushing Procedure
1. Shut off the sprayer. Lock the gun trigger safety le-
ver.
Open the bypass valve ONE turn counterclock-
wise. Raise the fluid pump just above the adhesive
and turn on the sprayer to drain the adhesive. Now
turn
of f the sprayer . See Fig. 8.
2. Place the fluid pump in a grounded pail of solvent.
3. Check to be sure the trigger safety lever is locked.
Remove
the spray tip from the gun. Unlock the safety
lever. Hold a metal part of the gun firmly to the side
of a grounded metal pail. Close the bypass valve.
Trigger the gun into the pail. T urn on the sprayer .
Watch
the side of the pail for solvent to appear . Then
release the gun trigger . T urn of f the sprayer .
4. With
the bypass valve (66) closed, turn on the spray -
er,
trigger the gun into the flushing pail and allow the
solvent to circulate through the hose and gun for two
to three minutes, using the lowest possible pressure.
See Fig. 8. Release the gun trigger and lock the safe -
ty
lever . T urn of f the sprayer .
5. Open the bypass valve (66) ONE turn counter-
clockwise.
6. Raise the fluid pump above the solvent, turn on the
sprayer,
and allow the pump to run itself dry . T urn the
sprayer OFF.
7. Using
a clean pail of water or solvent, and the lowest
possible pressure, flush again to be sure all adhesive
particles are removed.
8. Remove the fluid strainer and clean it thoroughly .
9.
Now lubricate the inlet valve. See page 6.
Fig. 7
1 inch
(25 mm)
0269
5
Fig. 8
0275
0270
1
3
4
2
Decrease pressure
(counterclockwise).
Increase pressure (clockwise).
Open (counterclockwise).
Close (clockwise).
66
41
3
4
2
11
Fig. 9
0276
ÄÄ
ÄÄ
ÄÄ
ÄÄ
Maintain firm metal–
to–metal contact
between gun and con -
tainer
1
1

 
Troubleshooting
WARNING
To reduce the risk of serious injury , including fluid in -
jection, always follow the Pressure Relief Proce-
dure Warning on page 2 before checking or repair-
ing
any part of the spray system.
NOTE: Repairs, other than those for which instructions
are
given on page 10, should be performed by a trained
and qualified repair agency .
NOTE:
If your sprayer is not operating well, or will not op -
erate at all, check for obvious problems first. Follow the
Startup procedure exactly (see page 5). Then if the
sprayer won’t start, use the T roubleshooting Chart for
help
in identifying the possible cause.
NOTE: Remember , taking the time after each use of the
sprayer to perform all of the maintenance procedures
given on page 6 and 7 will help prevent down time and
costly
repair bills.
PROBLEM CAUSE SOLUTION
“Fogging” spray pattern T oo much pressure. T urn the pressure down.
Spray gun won’t shut of f W orn ball Repair gun; order kit no. 218–588.
W orn dif fuser Replace gun.
Fluid build-up between needle and
diffuser
Disassemble and clean gun.
Spray gun leaks W orn seal or loose fluid fitting Repair gun; order Kit no. 218–588;
tighten
fluid fitting.
Spray gun won’t spray , or low
output from gun
Fluid supply empty Refill and reprime system.
Spray tip clogged Use Reverse-A-Clean feature to
clear
tip clog; see page 12.
Gun filter , if used, is clogged Clean or replace.
Sprayer will not start Sprayer not plugged in Plug in.
ON/OFF switch turned of f T urn switch on.
Sprayer left pressurized when shut
off
Relieve pressure first, then start.
Motor overheated Shut off, relieve pressure, allow to
cool.
NOTE: Sprayer restarts automati-
cally
when cool if it is left on.
Blown building fuse or circuit
breaker tripped
Replace or reset.
No voltage or low voltage in
electrical outlet
Test the outlet or try plugging spray -
er
into another outlet.
Damaged power supply cord or
extension cord, or wrong type of
extension cord
Return for repair; use only 3 wire, 16
gauge (minimum) extension cord
with
a 3 prong plug and a maximum
length of 30 m (100 foot).
Starter switch (18a) damaged Replace; see page 18.
Motor worn or damaged Return for repair .
Motor runs but sprayer won’t run Air in diaphragm housing Bleed air .

 
PROBLEM CAUSE SOLUTION
Sprayer starts but will not suck fluid. Fluid supply empty . Refill and prime pump.
Inlet screen clogged Clean.
Inlet valve stuck or damaged See page 18.
Outlet valve stuck See page 18.
Air trapped in hydraulic system See page 18, Diaphragm , step 9.
Hydraulic oil level low or empty See page 14.
Wrong grade of hydraulic oil or
wrong
fluid in hydraulic system
Use only Graco approved hydraulic
oil, part no. 218–797.
Inlet valve not tight T ighten; see page 14.
Damaged diaphragm Replace; see page 18.
Sprayer sucks fluid but does not
build
up pressure
Pressure control valve not turned up Adjust.
Outlet valve stuck, dirty or had worn
parts
See page 18.
Hydraulic oil low See page 14.
Inlet valve leaks See page 18.
Damaged diaphragm Replace; see page 18.
Damaged bypass valve Replace.
Damaged hydraulic system Return sprayer for repair .
Damaged fluid pump Replace.
Sprayer sucks fluid, builds pressure,
but pressure drops when gun is trig -
No spray tip on gun Shut of f sprayer and install tip.
but pressure drops when gun is trig -
gered Spray
tip orifice too large for the fluid
or worn tip
T ry a smaller tip or a new tip.
Inlet screen clogged Clean.
Optional gun filter clogged Clean or replace.
Optional gun filter screen too fine for
type of fluid
Install larger mesh filter or strain and
thin the fluid.
Fluid too thick Thin and/or strain.
W orn outlet valve Replace; see page 18.
Leaking bypass valve Replace.
W orn or damaged inlet valve See page 18.
Worn or damaged pressure control
valve
See page 18.
Pressure fluctuations Outlet valve stuck, dirty or worn See page 18.
Leaking or dirty bypass valve Replace.
Dirty , leaking, worn or damaged
inlet valve
Replace; see page 18.
Dirty pressure control knob Clean or replace; see page 18.
Damaged diaphragm, or fluid pump,
or hydraulic system
Return for repair .
Fluid in hydraulic system Ruptured diaphragm Return for repair .
Hydraulic oil in fluid Ruptured diaphragm Return for repair .

 
Service
Repairs, other than those for which instructions are given
below, should be performed by a trained and qualified re -
pair
agency .
WARNING
To reduce the risk of injury , including fluid injection,
splashing in the eyes or on the skin, or injury from
moving parts, always follow the Pressure Relief
Procedure Warning on page 2 before checking or
repairing
any part of the spray system.
Inlet Check V
alve . See Fig. 10.
1. Unscrew the inlet check valve (26) from the fluid
pump (22).
2. Clean
the gasket (26a), the inlet valve (26), and the
fluid pump (22) threads and check for erosion. If any
of the parts are eroded, replace them.
3. Be sure the threads in the fluid pump are clean.
4. Lubricate the threads of the inlet valve with petro-
leum
jelly . Install the gasket on the valve, then install
the valve and torque it to 320–360 in–lb (36–41 N.m).
Outlet Check V alve. See Fig. 10.
1. Unscrew the plug (28d) and the housing (28b).
2. Use a pick, such as a dentist’ s pick, to remove the
seal (28a) from the fluid pump (23). It may be hard
to remove.
DO NOT LEA VE THE SEAL IN THE
fluid
pump HOUSING.
3. Clean the parts thoroughly, including the threads in
the
pump, with a compatible solvent. Check all parts
for wear or damage and replace as needed.
4. Lubricate the threads of the housing (28b) and plug
(28d).
5. Install a NEW seal (28a) in the pump housing. AL-
WAYS
replace the seal (28a). Do not try to reuse the
old seal as it will be deformed.
CAUTION
Be sure you do not install a new seal until the old one
is removed. Having two seals in the valve will cause
performance problems.
6. Install the housing (28b) and torque to 125–150 in–lb
(14–17 N.m).
7. The last coil on one end of the spring is turned in.
Place
this end over the stud in the plug (28d). Install
the ball (28e), washer (28f) and plug, and torque to
plug
to 380–300 in–lb (32–34 N.m).
Pressure Control. See Fig. 10.
When removing the pressure control (4) to check or clean
it, always replace the seal (4a). When replacing the pres -
sure
control, torque the new control (4) to 125–150 in–lb
(14–17 N.m).
Starter Switch. See Fig. 10.
Remove the cover of the switch box. Remove the two
screws
holding the starter switch (18a). Remove the old
switch and install a new one.
Diaphragm. See Fig. 10.
1. Remove the inlet strainer (27). Remove the four fluid
pump screws (25) and lockwashers (24).
2. Remove the bypass valve (66) and the fluid outlet
nipple (67), and then remove the screws (35) and
shield (3).
3. Remove
the screw (36) and lockwasher (37) from the
bracket (38).
4. Pull
the fluid pump assembly away from the hydraulic
housing (20) and remove the old diaphragm (21).
CAUTION
Never start the electric motor with the inlet valve (26)
removed, as it will severely damage the diaphragm.
CAUTION
Be careful not to get any dirt or adhesive on the new
diaphragm or the hydraulic housing. Contaminants in
the hydraulic system can cause the sprayer to mal-
function
and result in costly damage to the sprayer .
DO
NOT T AMPER with the nut (C). The nut is factory
set to hold the spring to a specific dimension.
5. Check the gasket (22a) for wear or damage and re -
place
it if needed. Clean the top of the fluid pump and
the hydraulic housing thoroughly .
6. Install the new diaphragm assembly (21), lubricate
the internal threads of the housing (20), and reas-
semble
the parts.

 
Service
7. Lubricate the screws (25) and then install and torque
them to 170–200 in–lb (19–23 N.m).
CAUTION
Whenever you remove the fluid pump screws, torque
them as instructed above, and then retorque them af -
ter
3 to 5 hours of operation.
8. Check the hydraulic oil level and add Graco-ap-
proved oil as necessary until the level is 1 inch (25
mm)
from the top of the plate. See Fig. 1 1.
9. Turn the pressure control fully counterclockwise
(no
pressure). Plug in the sprayer and turn it on. Run
the sprayer for two minutes to fill the hydraulic sys-
tem.
Increase the pressure to maximum and turn the
sprayer on and of f four times to help rid the hydraulic
system of air .
Fig. 10
21
22a
22b
26a
26
27
25
24
28d
28f 28c
28e
28b
28a
C
4
4a
38
37
36
66
35
3
67
20
28
18a
0284
1
3
4
2
Torque
to 125–150 in–lb (14–17 N.m).
Apply sealant to the threads.
Lubricate the internal threads.
T orque to 125–150 in–lb (14–17 N.m).
T orque to 280–300 in–lb (32–34 N.m).
Lubricate the threads.
T orque to 320–360 in–lb (36–41 N.m).
T orque to 170–200 in–lb (19–23 N.m).
Do not alter the position of the nut.
The start switch is located
in the switch box.
5
7
8
6
10
1
2
3
2
4
5
67
10
8
6
9
9

 
Parts
38
34
56
37
60
1
59
54
55
86
56
8
70Y
13
14
71
9
65
49
50
48
53
7
89
6
5
52
4
4a
40
47
45
46
44
64
42
43
66
35 3
63
67
2
16
19
27
18
41
39
61
62
37
36
33
17
92Y
97Y
Y95
40
57
58
0280
98
99
75
1
3
4
2
Lubricate the threads. T orque to 40–45 in–lb
(54–60 N.m).
T orque to 130–140 in–lb (15–16 N.m).
Apply tape to the top and bottom threads.
See Detail A, page 14.
T orque to 70–90 in–lb (8–10 N.m).
The tube must drop freely in the pipe (1).
Apply sealant to the threads.
The seal in the bearing must face down.
Apply threads sealant to the motor tie bolts.
See Detail B, on page 14.
5
7
8
6
10
3
2
5
7
8
6
10
1
4
83
9
9
PTFE

 
Parts
MODEL 61–251
Part No. 231–109, Series C
NOTE: Part numbers and drawings for items 10 to12,
15,
18a, 20 to 26, 28, 68, 93, 94, 96, 99 to103
are shown on page 22.
Ref.
No.
Part No. Description Qty.
Ref.
No. Part No. Description Qty.
1 180–462
PIPE, pump, 5 gallon size 1
2 180–467
TUBE, , 5 gallon size 1
3 275–658
SHIELD 1
4 218–728
CONTROL, pressure,
Includes 4a 1
4a 180–447 .SEAL 1
5 108–152 VAL VE, plug, fill 1
6 180–983 PLUG, fill 1
7 275–637 COVER, pump housing 1
8 218–743 ST AND, pump 1
9 180–396 HOUSING, motor 1
13 104–859 SCREW
, mach; pan head; T ype B,
self –tapping; No. 10 x 0.375” 2
14 180–931 SUPPORT
, leg 1
16 108–175
PLUG 4
17 218–651
CORD SET , power , 60 Hz 1
18 185–635 MOT
OR, electric, 1/2 HP , 1 15V,
60Hz; 1725 RPM, single phase,
Includes 18a 1
18a 110–900 .STAR
TER SWITCH 1
19 156–823
UNION, 1/4 npt(m) x
1/4 npt swivel 1
27 218–798 STRAINER 1
33 186–120 LABEL, identification 1
34 187–952 HOUSING, pressure control 1
35 105–335 SCREW , cross head
recessed; M4 x 0.7 x 10
2
36
107–530 CAPSCREW , soc hd, hex;
M6 x 1.0 1
37
108–050 LOCKW ASHER, spring, Sz 6 2
38
180–648 BRACKET , shroud
39 183–839 NUT , hex; M25 x 1.0 1
40
180–447 SEAL, washer 2
41
103–255 O–RING, cylinder 1
42
183–840 CYLINDER, pump 1
43
108–153 FITTING, hose, barbed 1
44 107–51
1 SPRING, compression 1
45
180–479 PIST ON 1
46
180–480 W ASHER, spring 1
47
107–517 RING, retaining, external 1
48
107–524 RING, retaining, external 1
49 107–513 KEY
, woodruff 1
50
218–909 ECCENTRIC ASSEMBL Y1
52
108–042 SCREW , cross head
recessed; M4 x 14.0
8
53
180–650 GASKET , housing 1
54
107–518 BEARING, ball 1
55
107–519 SEAL, shaft 1
56
108–288 CAPSCREW , sch; M6 x 16 3
57
108–165 P ACKING, o–ring, Buna–N 1
58
181–032 SEAL, tube 1
59
180–466 ROD, displacement, 5 gallon 1
60
108–151 NUT , hex; 9/16” thread 1
61
108–053 CAPSCREW , hex hd;
M4 x 0.7 x 10 1
62
107–584 W ASHER, plain 1
63
108–154 FITTING, hose, barbed 1
64
180–996 TUBE, filter 1
65 180–998 FIL
TER, hydraulic oil 1
66
235–198 BYP ASS V AL VE ASSEMBLY 1
67 169–797 ADAPTER, 1/8 npt to 1/4 npsm 1
69Y
185–653 LABEL, serial & warning 1
70Y
185–952 LABEL, warning 1
71
186–121 LABEL, identification 1
75 224–771 SEA
T KIT 1
81Y179–761 T
AG, warning 1
83
186–122 LABEL 1
84 186–549 TUBE, drain 1
85 102–478
TIE, strap 1
86
100–086 W ASHER, plain, 3/16” 2
89 108–284 O–RING 1
90 218–933 SPRING SET ,
includes 2 replacement
springs, same as item 28c
1
92Y181–325
LABEL, warning 1
95Y186–126
LABEL, warning 1
97Y185–955*
LABEL, DANGER, “French” 1
Y
Replacement Danger and W arning labels, tags and
cards are available at no cost.

 
Parts
Ref.
No.
Part No. Description Qty.
10 105–659 T
OGGLE BOOT 1
11 105–679 SWITCH, toggle 1
12 105–774 PLA
TE, switch, ON/OFF 1
15 106–013
STRAIN RELIEF BUSHING 1
18a 110–900 .STAR
TER SWITCH 1
20 180–406
HOUSING, diaphragm 1
21 218–727
DIAPHRAGM ASSEMBL Y 1
22 224–624
PUMP HOUSING KIT
Includes 22a, 22b 1
22a 187–185
GUIDE, diaphragm 1
22b 187–339
HOUSING, pump 1
24 109–042 W
ASHER, spring, rib 4
25 107–514 CAPSCREW
, hex head,
M8 x 1.25 mm 4
26 218–726 VAL
VE, inlet check
Includes replaceable item 26a 1
26a 180–446 .GASKET 1
28 236–954 OUTLET CHECK V AL VE ASSY
Includes items 28a–28f 1
28a 180–455 .SEAL, washer 1
28b 218–968 .HOUSING, seat, valve 1
28c 112–619 .SPRING, compression 1
28d 218–505
.PLUG, ball stop 1
28e 1 12–618 .BALL, carbide 1
28f 180–454 .W ASHER 1
68 186–334
ADAPTER, tip 1
93 166–969 WASHER 1
94 110–761 TIP
, spray; 16” fan, 0.031 orifice 1
96 220–251 TIP
GUARD
Includes washer , item 93 1
98 223–541 HOSE,
coupled 1/4 x 50’ 1
99 204–940 SWIVEL,
straight 1
100 214–701
HOSE, coupled, 3/16” x 3’ 1
101 222–002 GUN, Basic
see 307–821 for parts 1
102 218–245 TUBE,
extension 1
103 180–137 NUT
, gun 1
0281
100
101
99
98
93
103
102
68
94
96
20
21
22a
22b
26a
26
24
25
28a
28b
28c
28f
28d
DET AIL A
0281
1
3
4
2
Lubricate the threads.
T orque to 125–150 in–lb (14–17 N.m).
T orque to 280–300 in–lb (32–34 N.m).
T orque to 170–200 in–lb (19–23 N.m).
T orque to 320–260 in–lb (36–41 N.m).
Do not alter the position of the nut.
5
6
6
2
1
28e
3
4
5
10
12
11
15
Ref
17
DET AIL B
BLACK
WHITE
GREEN
18a
0282
1The
starter
switch
is located in this
box.
1

 
French 185–956
Spanish 185–961
German 186–041
Greek 186–045
Korean 186–049
English 185–953
Danger Labels
The English language DANGER label shown on
page 1 and a French version of the same label, are
on your sprayer . If you have operators who do not
read English or French, order one of the following
labels to apply to your sprayer . Apply the label at A
for the best visiblity . Order the labels directly from
your Graco distributor without charge. Call
1–800–328–0211
A
Manual
Change Summary
Assembly
Changed
Part
Status
Ref
No.
Part No. Part Name
Model
61–251
Sprayer
Old
New
Old
New
Delete
Delete
Add
Add
27
27
28
28
28c
28e
28c
28e
108–143
218–798
218–732
236–954
107–521
101–701
112–619
112–618
Strainer
Strainer
Outlet valve
Outlet valve
Spring
Ball
Spring
Ball
The complete old and new outlet check valves are inter -
changeable. However, the new spring and balls are not
interchangeable
with the old ones.

 
Technical Data
Power Requirements 120 V AC, 60 Hz, . . . . . . . . . . . . .
1 Phase, 15 AMP minimum
Pressure Operating Range 0–3000 psi . . . . . . . . . . . . .
(0 – 210 bar)
Maximum Delivery 0.28 GPM (1.1 liter/min) . . . . . . . . . .
Power Cord No. 16 A WG, 3 wire, . . . . . . . . . . . . . . . . . .
8.5 feet (2.6 m) long
Inlet Strainer 16 mesh . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Outlet Nipple 1/4 npsm (m). . . . . . . . . . . . . . . . . . . .
Weight – without hose and gun 33 lb (14.8 Kg) . . . . . . .
Dimensions Height: 20 inch (508 mm) . . . . . . . . . . . . . . .
Width: 17.5 inch (444.5 mm)
Depth: 17.5 inch (444.5 mm)
W etted Parts Stainless Steel, Zinc-Plated Steel, . . . . .
Carbide, Aluminum, Nylon, Delrin r , Monel
Delrin r is a registered trademark of the DuPont Company
Ordering and
T echnical Assistance
TO PLACE AN ORDER , contact your Graco distrib -
utor
, or call this number to identify the distributor
closest to you: 1–800–367–4023 T oll Free
FOR TECHNICAL ASSIST ANCE, service repair
information or assistance regarding the application of
Graco equipment: 1–800–543–0339 T oll Free
The Graco Warranty and Disclaimers
WARRANTY
Graco
warrants all equipment manufactured by it and bearing its name to be free from defects in material and workmanship on
the date of sale by an authorized Graco distributor to the original purchaser for use. As purchaser ’ s sole remedy for breach of this
warranty, Graco will, for a period of twelve months from the date of sale, repair or replace any part of the equipment proven defec -
tive,
with the exception of defects in parts on the drive train/gear box on EM and GM sprayers or power train on EH and GH
sprayers, which will be repaired or replaced for twenty-four months from the date of sale for Gas–Hydraulic (GH) and Gas-
Mechanical (GM) sprayers and for thirty-six months from the date of sale for Electric-Mechanical (EM), Electric-Hydraulic (EH),
390st and 490st sprayers . This warranty applies only when the equipment is installed, operated and maintained in accordance
with Graco’ s written recommendations.
This warranty does not cover , and Graco shall not be liable for , any malfunction, damage or wear caused by faulty installation,
misapplication, abrasion, corrosion, inadequate or improper maintenance, negligence, accident, tampering, or substitution of
non–Graco component parts. Nor shall Graco be liable for malfunction, damage or wear caused by the incompatibility with Graco
equipment of structures, accessories, equipment or materials not supplied by Graco, or the improper design, manufacture, instal
-
lation, operation or maintenance of structures, accessories, equipment or materials not supplied by Graco.
This warranty is conditioned upon the prepaid return of the equipment claimed to be defective to an authorized Graco distributor
for verification of the claim. If the claimed defect is verified, Graco will repair or replace free of charge any defective parts. The
equipment will be returned to the original purchaser transportation prepaid. If inspection of the equipment does not disclose any
defect in material or workmanship, repairs will be made at a reasonable charge, which charges may include the costs of parts,
labor and transportation.
DISCLAIMERS AND LIMITATIONS
The terms of this warranty constitute purchaser ’ s sole and exclusive remedy and are in lieu of any other warranties (express or
implied), including warranty of merchantability or warranty of fitness for a particular purpose, and of any non–contractual
liabilities, including product liabilities, based on negligence or strict liability . Every form of liability for direct, special or consequen -
tial damages or loss is expressly excluded and denied. In no case shall Graco’ s liability exceed the amount of the purchase price.
Any action for breach of warranty must be brought within two (2) years of the date of sale.
EQUIPMENT NOT COVERED BY GRACO WARRANTY
Graco makes no warranty , and disclaims all implied warranties of merchantability and fitness for a particular purpose , with
respect to accessories, equipment, materials, or components sold but not manufactured by Graco. These items sold, but not
manufactured by Graco (such as electric motor , switches, hose, etc.) are subject to the warranty , if any , of their manufacturer .
Graco will provide purchaser with reasonable assistance in making any claim for breach of these warranties.
ROBERTS CONSOLIDATED INDUSTRIES, INC.
P
.O. Box 1250 / 600 N. Baldwin Park Blvd.
City of Industry , California 91749
(213) 338–731 1 or (800) 423–9467
PRINTED IN U.S.A. 308–021 November , 1989; Revised December , 1994