Graco Dura-Flo 900 Operation manual

308353
Rev. E
First choice when
quality counts. t
INSTRUCTIONS-PARTS LIST
INSTRUCTIONS
This manual contains important
warnings and information.
READ AND KEEP FOR REFERENCE.
CARBON STEEL
Dura-Flot 900 Pumps
With Severe-Duty Rod and Cylinder
Refer to page 2 for a List of Models; page 3 for the Table of Contents.
05195B
Model 237279
05181B
Model 236475
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441
ECOPYRIGHT 1994, GRACO INC.
Graco Inc. is registered to I.S. EN ISO 9001

2 308353
List of Models
Pump Part No.
and Series Pump Model
Displacement
Pump Part No.
and Series Ratio
Maximum Fluid
Working Pressure
Maximum Air/
Hydraulic
Input Pressure
237279,
Series A
Senatorr236466, Series A 17:1 11 MPa, 117 bar
(1700 psi)
0.7 MPa, 7 bar
(100 psi)
237284,
Series A
Bulldogr236466, Series A 28:1 19 MPa, 193 bar
(2800 psi)
0.7 MPa, 7 bar
(100 psi)
237292,
Series A
Reduced Icing
Quiet Bulldogr
236466, Series A 28:1 19 MPa, 193 bar
(2800 psi)
0.7 MPa, 7 bar
(100 psi)
236475,
Series A
Kingt236466, Series A 56:1 34 MPa, 345 bar
(5000 psi)
0.6 MPa, 6 bar
(90 psi)
240946,
Series A
Quiet Kingt236466, Series A 56:1 34 MPa, 345 bar
(5000 psi)
0.6 MPa, 6 bar
(90 psi)
237278,
Series A
Reduced Icing
Quiet Kingt
236466, Series A 56:1 34 MPa, 345 bar
(5000 psi)
0.6 MPa, 6 bar
(90 psi)
237283,
Series A
Kingt
(55 gallon size)
236466, Series A 56:1 34 MPa, 345 bar
(5000 psi)
0.6 MPa, 6 bar
(90 psi)
237290,
Series A
Viscountr
(hydraulic)
236466, Series A 3.5:1 34 MPa, 345 bar
(5000 psi)
9.9 MPa, 99 bar
(1428 psi)
hydraulic pressure
917028,
Series A
Viscountr II
(hydraulic)
240682, Series A 3.5:1 34 MPa, 345 bar
(5000 psi)
9.9 MPa, 99 bar
(1428 psi)
hydraulic pressure

 
Table of Contents
List of Models 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warnings 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Change Summary 51. . . . . . . . . . . . . . . . . . . . .
Installation 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
All Pumps 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General Information 7. . . . . . . . . . . . . . . . . . . . . . . . .
Grounding 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air-Powered Pumps 8. . . . . . . . . . . . . . . . . . . . . . . . .
System Accessories 8. . . . . . . . . . . . . . . . . . . . . . . .
Typical Air-Powered Installation 9. . . . . . . . . . . . . . .
Hydraulic-Powered Pumps 10. . . . . . . . . . . . . . . . . .
System Accessories 10. . . . . . . . . . . . . . . . . . . . . . .
Typical Hydraulic-Powered Installation 11. . . . . . . .
Operation/Maintenance 12. . . . . . . . . . . . . . . . . . . . . . .
All Pumps 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Relief Procedure 12. . . . . . . . . . . . . . . . . .
Packing Nut/Wet-Cup 12. . . . . . . . . . . . . . . . . . . . . .
Air-Powered Pumps 13. . . . . . . . . . . . . . . . . . . . . . . .
Flush the Pump Before First Use 13. . . . . . . . . . . .
Starting and Adjusting the Pump 13. . . . . . . . . . . . .
Shutdown and Care of the Pump 14. . . . . . . . . . . . .
Flushing 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hydraulic-Powered Pumps 15. . . . . . . . . . . . . . . . . .
Flushing the Pump Before First Use 15. . . . . . . . . .
Starting and Adjusting the Pump 15. . . . . . . . . . . . .
Shutdown and Care of the Pump 16. . . . . . . . . . . . .
Flushing 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Chart 17. . . . . . . . . . . . . . . . . . . . . . .
Service 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Required Tools 18. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnecting the Displacement Pump 18. . . . . . .
Reconnecting the Displacement Pump 18. . . . . . . .
Displacement Pump Service 20. . . . . . . . . . . . . . . .
Parts 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Part No. 236475 Pump, Series A, 56:1 Ratio
with King Air Motor 26. . . . . . . . . . . . . . . . . . . . . . . . .
Part No. 237278 Pump, Series A, 56:1 Ratio
with Reduced Icing Quiet King Air Motor 26. . . . . .
Part No. 237283 Pump, Series A, 56:1 Ratio
with King Air Motor (55 gallon/200 liter size) 27. . .
Part No. 240946 Pump, Series A, 56:1 Ratio
with Quiet King Air Motor 28. . . . . . . . . . . . . . . . . . .
Part No. 237279 Pump, Series A, 17:1 Ratio
with Senator Air Motor 28. . . . . . . . . . . . . . . . . . . . . .
Part No. 237284 Pump, Series A, 28:1 Ratio
with Bulldog Air Motor 29. . . . . . . . . . . . . . . . . . . . . .
Part No. 237292 Pump, Series A, 28:1 Ratio
with Reduced Icing Quiet Bulldog Air Motor 29. . . .
Part No. 237290 Pump, Series A,
with Viscount Hydraulic Motor 30. . . . . . . . . . . . . . .
Part No. 917028 Pump, Series A,
with Viscount II Hydraulic Motor 31. . . . . . . . . . . . . .
Common Displacement Pump Parts 32. . . . . . . . . .
Packing Kits 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Leather Packing Kit 237163, for Standard
Displacement Pump 236466, Series A 33. . . . . . . .
Packing Kit 237164, for Optional
Displacement Pump 236896, Series A 33. . . . . . . .
UHMWPE and Leather Packing Kit
237165 (Optional) 33. . . . . . . . . . . . . . . . . . . . . . . . . .
UHMWPE and Packing Kit 237709, for
Standard Displacement Pump
240682, Series A 34. . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Data 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model 236475 and 237283 King Pumps 36. . . . . . .
Model 240946 Quiet King and 237278
Reduced Icing Quiet King Pumps 38. . . . . . . . . . . .
Model 237284 Bulldog Pump 40. . . . . . . . . . . . . . . .
Model 237292 Reduced Icing Quiet
Bulldog Pump 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model 237279 Senator Pump 44. . . . . . . . . . . . . . . .
Model 237290 Viscount Pump 46. . . . . . . . . . . . . . .
Model 917028 Viscount II Pump 48. . . . . . . . . . . . .
Dimensions 50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pump Dimensions 50. . . . . . . . . . . . . . . . . . . . . . . . .
Mounting Hole Layout 50. . . . . . . . . . . . . . . . . . . . . .
Graco Standand Warranty 52. . . . . . . . . . . . . . . . . . . .
Graco Phone Number 52. . . . . . . . . . . . . . . . . . . . . . . .
PTFE
PTFE

4 308353
Symbols
Warning Symbol
WARNING
his symbol alerts you to the possibility of serious
injury or death if you do not follow the instructions.
Caution Symbol
CAUTION
This symbol alerts you to the possibility of damage to
or destruction of equipment if you do not follow the
instructions.
WARNING
INSTRUCTIONS
EQUIPMENT MISUSE HAZARD
Equipment misuse can cause the equipment to rupture or malfunction and result in serious injury.
DThis equipment is for professional use only.
DRead all instruction manuals, tags, and labels before operating the equipment.
DUse the equipment only for its intended purpose. If you are uncertain about usage, call your Graco
distributor.
DDo not alter or modify this equipment.
DCheck equipment daily. Repair or replace worn or damaged parts immediately.
DDo not exceed the maximum working pressure of the lowest rated system component. Refer to the
Technical Data on pages 36–46 for the maximum working pressure of this equipment.
DUse fluids and solvents which are compatible with the equipment wetted parts. Refer to the Tech-
nical Data section of all equipment manuals. Read the fluid and solvent manufacturer’s warnings.
DDo not use hoses to pull equipment.
DRoute hoses away from traffic areas, sharp edges, moving parts, and hot surfaces. Do not expose
Graco hoses to temperatures above 82_C (180_F) or below –40_C (–40_F).
DWear hearing protection when operating this equipment.
DDo not lift pressurized equipment.
DComply with all applicable local, state, and national fire, electrical, and safety regulations.

 
WARNING
INJECTION HAZARD
Spray from the gun, leaks or ruptured components can inject fluid into your body and cause extremely
serious injury, including the need for amputation. Fluid splashed in the eyes or on the skin can also
cause serious injury.
Fluid injected into the skin might look like just a cut, but it is a serious injury. Get immediate medi-
cal attention.
Do not point the gun at anyone or at any part of the body.
Do not put your hand or fingers over the spray tip.
Do not stop or deflect leaks with your hand, body, glove or rag.
Do not “blow back” fluid; this is not an air spray system.
Always have the tip guard and the trigger guard on the gun when spraying.
Check the gun diffuser operation weekly. Refer to the gun manual.
Be sure the gun trigger safety operates before spraying.
Lock the gun trigger safety when you stop spraying.
Follow the Pressure Relief Procedure on page 12 if the spray tip clogs and before cleaning,
checking or servicing the equipment.
Tighten all fluid connections before operating the equipment.
Check the hoses, tubes, and couplings daily. Replace worn or damaged parts immediately.
Do not repair high pressure couplings; you must replace the entire hose.
Fluid hoses must have spring guards on both ends, to help protect them from rupture caused by
kinks or bends near the couplings.
MOVING PARTS HAZARD
Moving parts, such as the air motor piston, can pinch or amputate your fingers.
Keep clear of all moving parts when starting or operating the pump.
Before servicing the equipment, follow the Pressure Relief Procedure on page 12 to prevent the
equipment from starting unexpectedly.

6 308353
WARNING
FIRE AND EXPLOSION HAZARD
Improper grounding, poor ventilation, open flames or sparks can cause a hazardous condition and
result in a fire or explosion and serious injury.
Ground the equipment and the object being sprayed. Refer to Grounding on page 7.
If there is any static sparking or you feel an electric shock while using this equipment, stop spray-
ing immediately. Do not use the equipment until you identify and correct the problem.
Provide fresh air ventilation to avoid the buildup of flammable fumes from solvents or the fluid
being sprayed.
Keep the spray area free of debris, including solvent, rags, and gasoline.
Electrically disconnect all equipment in the spray area.
Extinguish all open flames or pilot lights in the spray area.
Do not smoke in the spray area.
Do not turn on or off any light switch in the spray area while operating or if fumes are present.
Do not operate a gasoline engine in the spray area.
TOXIC FLUID HAZARD
Hazardous fluid or toxic fumes can cause serious injury or death if splashed in the eyes or on the skin,
inhaled, or swallowed.
Know the specific hazards of the fluid you are using.
Store hazardous fluid in an approved container. Dispose of hazardous fluid according to all local,
state and national guidelines.
Always wear protective eyewear, gloves, clothing and respirator as recommended by the fluid and
solvent manufacturer.

308353 7
Installation
(ALL PUMPS)
General Information
NOTE: Reference numbers and letters in parentheses
in the text refer to the callouts in the figures and the
parts drawing.
NOTE: Always use Genuine Graco Parts and Acces-
sories, available from your Graco distributor. Refer to
Product Data Sheet, Form No. 305715 (Senator
Pumps), Form No. 305716 (Bulldog Pumps), Form No.
305717 (King Pumps), and Form No. 305718 (Viscount
Pumps). If you supply your own accessories, be sure
they are adequately sized and pressure rated for your
system.
Grounding
WARNING
FIRE AND EXPLOSION HAZARD
Before operating the pump, ground the
system as explained below. Also read
the section FIRE AND EXPLOSION
HAZARD on page 6.
1. Pump: use a ground wire and clamp. See Fig. 1.
Loosen the grounding lug locknut (W) and washer
(X). Insert one end of a 1.5 mm (12 ga) minimum
ground wire (Y) into the slot in lug (Z) and tighten
the locknut securely. Connect the other end of the
wire to a true earth ground. Order Part No. 237569
Ground Wire and Clamp.
Fig. 1
W
X
Y
Z

2. Air, hydraulic, and fluid hoses: use only electrically
conductive hoses.
3. Air compressor or hydraulic power supply: follow
manufacturer’s recommendations.
4. Spray gun: ground through connection to a prop-
erly grounded fluid hose and pump.
5. Fluid supply container: follow your local code.
6. Object being sprayed: follow your local code.
7. Solvent pails used when flushing: follow your local
code. Use only metal pails, which are conductive,
placed on a grounded surface. Do not place the
pail on a nonconductive surface, such as paper or
cardboard, which interrupts the grounding continu-
ity.
8. To maintain grounding continuity when flushing or
relieving pressure , hold a metal part of the spray
gun firmly to the side of a grounded metal pail,
then trigger the gun.

 
Installation
(AIR-POWERED PUMPS)
System Accessories
Fig. 2 is only a guide for selecting and installing sys-
tem components and accessories. Contact your Graco
distributor for assistance in designing a system to suit
your particular needs.
WARNING
A bleed-type master air valve (E) and a fluid drain
valve (M) are required in your system. These
accessories help reduce the risk of serious injury,
including fluid injection and splashing of fluid in the
eyes or on the skin, and injury from moving parts if
you are adjusting or repairing the pump.
The bleed-type master air valve relieves air trapped
between this valve and the pump after the air is
shut off. Trapped air can cause the pump to cycle
unexpectedly. Locate the valve close to the pump.
Order Part No. 107141.
The fluid drain valve assists in relieving fluid pres-
sure in the displacement pump, hose, and gun.
Triggering the gun to relieve pressure may not be
sufficient. Order Part No. 210658.
Air and Fluid Hoses
Be sure all air hoses (H) and fluid hoses (N and P) are
properly sized and pressure-rated for your system.
Use only electrically conductive hoses. Fluid hoses
must have spring guards on both ends. Use a whip
hose (P) and a swivel (R) between the main fluid hose
(N) and the gun (S) to allow freer gun movement.
Mounting Accessories
Mount the pump (A) to suit the type of installation
planned. Fig. 2 illustrates a cart mount system. Pump
dimensions and the mounting hole layout are shown
on page 50.
Air Line Accessories
Install the following accessories in the locations shown
in Fig. 2, using adapters as necessary:
An air line lubricator (D) provides automatic air
motor lubrication.
A bleed-type master air valve (E) is required in
your system to relieve air trapped between it and
the air motor when the valve is closed (see the
WARNING at left). Be sure the bleed valve is easi-
ly accessible from the pump, and is located down-
stream from the air regulator.
An air regulator (F) controls pump speed and out-
let pressure by adjusting the air pressure to the
pump. Locate the regulator close to the pump, but
upstream from the bleed-type master air valve.
A pump runaway valve (C) senses when the
pump is running too fast and automatically shuts
off the air to the motor. A pump which runs too fast
can be seriously damaged.
An air manifold (G) has a 3/4 npsm(f) swivel air
inlet. It mounts to the pump support bracket, and
provides ports for connecting lines to air-powered
accessories.
An air line filter (J) removes harmful dirt and
moisture from the compressed air supply. Also,
install a drain valve (W) at the bottom of each air
line drop, to drain off moisture.
A second bleed-type air valve (K) isolates the air
line accessories for servicing. Locate upstream
from all other air line accessories.
Fluid Line Accessories
Install the following accessories in the locations shown
in Fig. 2, using adapters as necessary:
A fluid filter (L) with a 60 mesh (250 micron)
stainless steel element, to filter particles from the
fluid as it leaves the pump.
A fluid drain valve (M), which is required in your
system, helps relieve fluid pressure in the hose
and gun (see the WARNING at left).
A gun (S) dispenses the fluid. The gun shown in
Fig. 2 is an airless spray gun for light to medium
viscosity fluids.
A gun swivel (R) allows freer gun movement.
A suction kit (T) allows the pump to draw fluid
from a supply container.

308353 9
Installation

Fig. 2
KEY
APump
BCart
CPump Runaway Valve (location)
DAir Line Lubricator (location)
EBleed-Type Master Air Valve
(required, for pump)
FPump Air Regulator
GAir Manifold
HElectrically Conductive Air Supply Hose
JAir Line Filter
KBleed-Type Master Air Valve
(for accessories)
LFluid Filter
MFluid Drain Valve (required)
NElectrically Conductive
Fluid Supply Hose
PFluid Whip Hose
RGun Swivel
SAirless Spray Gun
TSuction Kit
YGround Wire and Clamp
(required; see page 7
for installation instructions)
TYPICAL AIR-POWERED INSTALLATION
A
B
C
D
E
F
G
H
JK
M
N
P
Y
MAIN AIR LINE
L
R
S
T

10 308353
Installation
(HYDRAULIC-POWERED PUMPS)
CAUTION
Keep the hydraulic supply system clean at all times.
Be sure that all hydraulic fluid lines are absolutely
clean. Blow out the lines with air and flush thoroughly
with solvent before connecting to the hydraulic
motor, to avoid introducing harmful contaminants into
the motor. Plug the hydraulic lines immediately when
they are disconnected.
Do not exceed 37.8 liter/min (10 gpm) hydraulic oil
volume to the motor, to avoid stalling the pump.
For optimum pump performance, keep the tempera-
ture of the hydraulic oil below 54_C (130_F).
System Accessories
Fig. 3 is only a guide for selecting and installing sys-
tem components and accessories. Contact your Graco
distributor for assistance in designing a system to suit
your particular needs.
WARNING
A fluid drain valve (M) is required in your system.
This accessory helps reduce the risk of serious
bodily injury, including fluid injection and splashing
of fluid in the eyes or on the skin, and injury from
moving parts if you are adjusting or repairing the
pump.
The fluid drain valve assists in relieving fluid pres-
sure in the displacement pump, hose, and gun.
Triggering the gun to relieve pressure may not be
sufficient. Order Part No. 210658.
Mounting Accessories
Mount the pump (A) to suit the type of installation
planned. Fig. 3 illustrates a wall mount system. Pump
dimensions and the mounting hole layout are shown
on page 50.
Filters
Be sure your hydraulic power supply is equipped with a
suction filter to the hydraulic pump and a system return
line filter (AA) of 10 micron size.
Carefully follow the manufacturer’s recommendations
on reservoir and filter cleaning, and periodic changes
of hydraulic fluid. Use only Graco-approved hydraulic
oil. Order Part No. 169236 for 19 liter (5 gal.) or Part
No. 207428 for 3.8 liter (1 gal.) power supplies.
Hydraulic Lines
The motor has a 3/4 npt(f) hydraulic oil supply fitting,
and a 1” npt(f) hydraulic oil return fitting. Use a mini-
mum 13 mm (1/2 in.) ID hydraulic supply line, and a
minimum 22 mm (7/8 in.) ID return line.
On the hydraulic supply line (C), install the following
accessories in the order shown in Fig. 3, using adapt-
ers as necessary:
DA shutoff valve (U) isolates the pump for service.
DA fluid pressure gauge (F) to monitor hydraulic
oil pressure to the motor and to avoid overpressur-
izing the motor or displacement pump, and a pres-
sure- and temperature-compensated flow con-
trol valve (G) to prevent the motor from running
too fast and possibly damaging itself.
DA pressure reducing valve (H), with a drain line
(E) run directly to the hydraulic return line (D).
DAn accumulator (J) to reduce the hammering ef-
fect caused by the motor reversing direction.
DA shutoff valve (V) isolates the pump for service.
DA filter (AA) of 10 micron size.
Hydraulic Motor Drip Pan
The hydraulic motor has a drip pan to collect any
leakage. Connect a 6 mm (1/4 in.) ID drain line (K) to
the barbed fitting on the drip pan, and place the free
end in a container to receive the drainage.
Fluid Supply Hoses
Be sure all fluid hoses (N and P) are properly sized
and pressure-rated for your system. Use only electri-
cally conductive hoses. Fluid hoses must have spring
guards on both ends. Use a whip hose (P) and a
swivel (R) between the main fluid hose (N) and the gun
(S) to allow freer gun movement.

308353 11
Installation
(HYDRAULIC-POWERED PUMPS)
Fluid Line Accessories
Install the following accessories in the locations shown
in Fig. 3, using adapters as necessary:
A fluid filter (L) with a 60 mesh (250 micron)
stainless steel element, to filter particles from the
fluid as it leaves the pump.
A fluid drain valve (M), which is required in your
system, helps relieve fluid pressure in the hose
and gun (see the WARNING on page 10).
A gun (S) dispenses the fluid. The gun shown in
Fig. 3 is an airless spray gun for light to medium
viscosity fluids.
A gun swivel (R) allows freer gun movement.
A suction kit (T) allows the pump to draw fluid
from a supply container.
KEY
APump
BWall Bracket
CHydraulic Supply Line
DHydraulic Return Line
EDrain Line (from pressure reducing valve)
FPressure Gauge
GFlow Control Valve
HPressure Reducing Valve
JAccumulator
KDrain Line (from motor drip pan)
LFluid Filter
MFluid Drain Valve (required)
NElectrically Conductive
Fluid Supply Hose
PFluid Whip Hose
RGun Swivel
SAirless Spray Gun
TDrum Suction Kit
UHydraulic Supply Line Shutoff Valve
VHydraulic Return Line Shutoff Valve
YGround Wire (required, see page 7 for
installation instructions)
AA Hydraulic Return Line Filter
04582B
Fig. 3
A
B
D
E
F
G
HJ
K
M
N
P
Y
200 LITER (55 GAL.)
DRUM
L
R
S
T
U
C
V
HYDRAULIC
POWER SUPPLY
DRAINAGE
CONTAINER
AA
TYPICAL HYDRAULIC-POWERED INSTALLATION

12 308353
Operation/Maintenance
(ALL PUMPS)
Pressure Relief Procedure
WARNING
INJECTION HAZARD
The system pressure must be manually
relieved to prevent the system from
starting or spraying accidentally. Fluid
under high pressure can be injected through the
skin and cause serious injury. To reduce the risk of
an injury from injection, splashing fluid, or moving
parts, follow the Pressure Relief Procedure
whenever you:
are instructed to relieve the pressure,
stop spraying,
check or service any of the system equipment,
or install or clean the spray tips.
1. Lock the gun trigger safety.
2. Shut off the air or hydraulic supply to the pump.
3. In air-powered systems, close the bleed-type
master air valve (required in your system).
In hydraulic-powered systems, close the hydraulic
supply line valve first , then the return line valve.
4. Unlock the gun trigger safety.
5. Hold a metal part of the gun firmly to the side of a
grounded metal pail, and trigger the gun to relieve
pressure.
6. Lock the gun trigger safety.
7. Open the drain valve (required in your system),
having a container ready to catch the drainage.
8. Leave the drain valve open until you are ready to
spray again.
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
tip guard retaining nut or hose end coupling and relieve
pressure gradually, then loosen completely. Now clear
the tip or hose.
Packing Nut/Wet-Cup
Before starting, fill the packing nut (2) 1/3 full with
Graco Throat Seal Liquid (TSL) or compatible solvent.
See Fig. 4.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure at left.
The packing nut is torqued at the factory and is ready
for operation. If it becomes loose and there is leaking
from the throat packings, relieve pressure, then
torque the nut to 128–156 N.m (95–115 ft-lb) using the
supplied wrench (110). Do this whenever necessary.
Do not overtighten the packing nut.

Fig. 4
110
2


Model 236475 Shown
Torque to 128–156 N.m
(95–115 ft-lb)

308353 13
Operation/Maintenance
(AIR-POWERED PUMPS)
Flush the Pump Before First Use
The pump is tested with lightweight oil, which is left in
to protect the pump parts. If the fluid you are using
may be contaminated by the oil, flush it out with a
compatible solvent. See Flushing on page 14.
Starting and Adjusting the Pump
1. See Fig. 2 on page 9. Connect the suction kit (T)
to the pump’s fluid inlet. Place the tube into the
fluid supply.
2. Close the air regulator (F).
3. Open the pump’s bleed-type master air valve (E).
4. Hold a metal part of of the gun (S) firmly to the
side of a grounded metal pail and hold the trigger
open.
5. Slowly open the regulator until the pump starts.
6. Cycle the pump slowly until all air is pushed out
and the pump and hoses are fully primed.
7. Release the gun trigger and lock the trigger safety.
The pump should stall against pressure.
8. If the pump fails to prime properly, open the drain
valve (M). Use the drain valve as a priming valve
until the fluid flows from the valve. Close the valve.
NOTE: When changing fluid containers with the hose
and gun already primed, open the drain valve (M) to
help prime the pump and vent air before it enters the
hose. Close the drain valve when all air is eliminated.
CAUTION
Do not allow the pump to run dry. It will quickly
accelerate to a high speed, causing damage. If your
pump is running too fast, stop it immediately and
check the fluid supply. If the container is empty and
air has been pumped into the lines, refill the con-
tainer and prime the pump and the lines, or flush and
leave it filled with a compatible solvent. Eliminate all
air from the fluid system.
9. With the pump and lines primed, and with ade-
quate air pressure and volume supplied, the pump
will start and stop as you open and close the gun.
In a circulating system, the pump will speed up or
slow down on demand, until the air supply is shut
off.
WARNING
COMPONENT RUPTURE HAZARD
To reduce the risk of overpressurizing
your system, which could cause compo-
nent rupture and serious injury, never
exceed the specified Maximum Incoming Air Pres-
sure to the pump (see the Technical Data, on
pages 36–44).
10. Use the air regulator (F) to control pump speed
and fluid pressure. Always use the lowest air
pressure necessary to get the desired results.
Higher pressures cause premature tip and pump
wear.

14 308353
Operation/Maintenance
(AIR-POWERED PUMPS)
Shutdown and Care of the Pump
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
For overnight shutdown, stop the pump at the bottom
of its stroke to prevent fluid from drying on the ex-
posed displacement rod and damaging the throat
packings. Relieve the pressure.
Always flush the pump before the fluid dries on the
displacement rod. See Flushing below.
Flushing
WARNING
FIRE AND EXPLOSION HAZARD
Before flushing, read the section FIRE
AND EXPLOSION HAZARD on page
6. Be sure the entire system and flush-
ing pails are properly grounded. Refer to
Grounding on page 7.
Flush with a fluid that is compatible with the fluid you
are pumping and with the wetted parts in your system.
Check with your fluid manufacturer or supplier for
recommended flushing fluids and flushing frequency.
Always flush the pump before fluid dries on the dis-
placement rod.
CAUTION
Never leave water or water-base fluid in the pump
overnight. If you are pumping water-base fluid, flush
with water first, then with a rust inhibitor such as
mineral spirits. Relieve the pressure, but leave the
rust inhibitor in the pump to protect the parts from
corrosion.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
1. Relieve the pressure.
2. Remove the spray tip from the gun.
3. Hold a metal part of the gun firmly to the side of a
grounded metal pail.
4. Start the pump. Always use the lowest possible
fluid pressure when flushing.
5. Trigger the gun.
6. Flush the system until clear solvent flows from the
gun.
7. Relieve the pressure.

308353 15
Operation/Maintenance
(HYDRAULIC-POWERED PUMPS)
Flush the Pump Before First Use
The pump is tested with lightweight oil, which is left in
to protect the pump parts. If the fluid you are using
may be contaminated by the oil, flush it out with a
compatible solvent. See Flushing on page 16.
Starting and Adjusting the Pump
1. Refer to Fig. 3 on page 11. Connect the suction kit
(T) to the pump’s fluid inlet, and place the tube into
the fluid supply.
2. Check the hydraulic fluid level before each use,
and add fluid as necessary.
3. Make certain that the supply line shutoff valve (U)
and the return line shutoff valve (V) are closed.
4. Start the hydraulic power supply.
5. Hold a metal part of the gun (S) firmly to the side
of a grounded metal pail and hold the trigger open.
6. Open the return line shutoff valve (V) first, then
slowly open the supply line shutoff valve (U).
7. Cycle the pump slowly until all air is pushed out
and the pump and hoses are fully primed.
8. Release the gun trigger and lock the trigger safety.
The pump should stall against pressure.
9. If the pump fails to prime properly, open the drain
valve (M). Use the drain valve as a priming valve
until the fluid flows from the valve. Close the valve.
NOTE: When changing fluid containers with the hose
and gun already primed, open the drain valve (M) to
help prime the pump and vent air before it enters the
hose. Close the drain valve when all air is eliminated.
10. With the pump and lines primed, and with ade-
quate hydraulic volume supplied, the pump will
start and stop as you open and close the gun. In a
circulating system, the pump will speed up or slow
down on demand, until the hydraulic power supply
is shut off.
11. Use the fluid pressure gauge (F) and flow control
valve (G) to control the pump speed and the fluid
outlet pressure. Always use the lowest hydraulic
flow and pressure necessary to get the desired
results. Higher pressures cause premature tip/noz-
zle and pump wear.
WARNING
COMPONENT RUPTURE HAZARD
To reduce the risk of overpressurizing
your system, which could cause compo-
nent rupture and serious injury, never
exceed the specified Maximum Incoming Air Pres-
sure to the pump (see the Technical Data on page
46).
To prevent overpressurizing the hydraulic motor or
its seals, always shut off the supply line valve (U)
first , then shut off the return line valve (V).
CAUTION
Do not allow the hydraulic oil temperature to exceed
54C (130F). The pump seals will wear faster and
leakage may occur if the pump is operated at higher
oil temperatures.

16 308353
Operation/Maintenance
(HYDRAULIC-POWERED PUMPS)
Shutdown and Care of the Pump
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
For overnight shutdown, stop the pump at the bottom
of its stroke to prevent fluid from drying on the ex-
posed displacement rod and damaging the throat
packings. Relieve the pressure.
Always flush the pump before the fluid dries on the
displacement rod. See Flushing below.
Flushing
WARNING
FIRE AND EXPLOSION HAZARD
Before flushing, read the section FIRE
AND EXPLOSION HAZARD on page
6. Be sure the entire system and flush-
ing pails are properly grounded. Refer to
Grounding on page 7.
Flush with a fluid that is compatible with the fluid you
are pumping and with the wetted parts in your system.
Check with your fluid manufacturer or supplier for
recommended flushing fluids and flushing frequency.
Always flush the pump before fluid dries on the dis-
placement rod.
CAUTION
Never leave water or water-base fluid in the pump
overnight. If you are pumping water-base fluid, flush
with water first, then with a rust inhibitor such as
mineral spirits. Relieve the pressure, but leave the
rust inhibitor in the pump to protect the parts from
corrosion.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
1. Relieve the pressure.
2. Remove the spray tip from the gun.
3. Hold a metal part of the gun firmly to the side of a
grounded metal pail.
4. Start the pump. Always use the lowest possible
fluid pressure when flushing.
5. Trigger the gun.
6. Flush the system until clear solvent flows from the
gun.
7. Relieve the pressure.

308353 17
Troubleshooting Chart
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
1. Relieve the pressure.
2. Check all possible causes and problems before
disassembling the pump.
PROBLEM CAUSE SOLUTION
The pump fails to oper-
ate.
Restricted air/hydraulic line or an inade-
quate air/hydraulic supply; closed or
clogged valves.
Clear the line; increase the air/hydraulic supply.
Check that the valves are open.
Obstructed fluid hose or gun;
the fluid hose ID is too small.
Open, clear*; use a hose with a larger ID.
Fluid has dried on the displacement rod. Clean the rod; always stop the pump at the bottom
of its stroke;
keep the wet-cup 1/3 filled with a compatible sol-
vent.
Dirty, worn, or damaged motor parts. Clean or repair; see the separate motor manual.
The pump operates,
but the output is low on
both strokes.
Restricted air/hydraulic line or an inade-
quate air/hydraulic supply; closed or
clogged valves.
Clear the line; increase the air/hydraulic supply.
Check that the valves are open.
Obstructed fluid hose or gun;
the fluid hose ID is too small.
Open, clear*; use a hose with a larger ID.
Worn packings in the displacement
pump.
Replace the packings.
The pump operates,
but the output is low on
the downstroke.
Held open or worn intake valve. Clear the valve; service.
The pump operates,
but the output is low on
the upstroke.
Held open or worn piston valve or pack-
ings.
Clear the valve; replace the packings.
Erratic or accelerated
pump speed.
Exhausted fluid supply. Refill the supply and prime the pump.
Held open or worn piston valve or pack-
ings.
Clear the valve; replace the packings.
Held open or worn intake valve. Clear the valve; service.
* To determine if the fluid hose or gun is obstructed, follow the Pressure Relief Procedure on page 12. Discon-
nect the fluid hose and place a container at the pump fluid outlet to catch any fluid. Turn on the air or hydraulic
power just enough to start the pump. If the pump starts when the air or hydraulic power is turned on, the ob-
struction is in the fluid hose or gun.
NOTE: If you experience air motor icing, call your Graco distributor.

18 308353
Service
Required Tools
Set of adjustable wrenches
Large pipe wrench
2-5/8 in. wrench
Torque wrench
Rubber mallet
O-ring pick
Large vise
Thread lubricant
Thread sealant
Disconnecting the Displacement Pump
1. Flush the pump, if possible. Stop the pump at the
bottom of its stroke.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
2. Relieve the pressure.
3. Disconnect the air or hydraulic hose and the fluid
hose. Plug all hydraulic hoses immediately, to
prevent contamination of the hydraulic system.
4. Disconnect the displacement pump (109) from the
motor (101) as follows. Note the relative position of
the pump’s fluid outlet (U) to the air (V) or hydrau-
lic inlet of the motor. If the motor does not require
servicing, leave it attached to its mounting. See
Fig. 5.
CAUTION
Be sure to use at least two people when lifting,
moving, or disconnecting the pump. This pump is too
heavy for one person. If you are disconnecting the
displacement pump from a motor which is still
mounted (for example, on a wall bracket), be sure to
support the displacement pump while it is being
disconnected, to prevent it from falling and causing
injury or property damage. Do this by securely brac-
ing the pump, or by having at least two people hold it
while another disconnects it.
If the pump is mounted on a cart, slowly tip the cart
backward until the handle rests on the ground, then
disconnect the displacement pump.
5. Using an adjustable wrench (or hammer and
punch), unscrew the coupling nut (106) from the
motor shaft (W). Take care not to lose or drop the
coupling collars (107). See Fig. 5.
NOTE: On Model 237283, disconnect the riser tube
(119) at either the elbow (120) or the connector (118).
See the Parts Drawing on page 27.
6. Hold the tie rod flats with a wrench to keep the
rods from turning. Unscrew the nuts (108) from the
tie rods (105). Carefully remove the displacement
pump (109) from the motor (101).
7. Refer to page 20 for displacement pump service.
To service the air or hydraulic motor, refer to the
separate motor manual, supplied.
Reconnecting the Displacement Pump
1. Make sure the coupling nut (106) and the coupling
collars (107) are in place on the displacement rod
(1). See Fig. 5.
2. Use at least two people to hold the displacement
pump while another reconnects it to the motor (see
the CAUTION at left). Orient the pump’s fluid
outlet (U) to the air inlet (V) or hydraulic inlet as
was noted in step 4 under Disconnecting the
Displacement Pump. Position the displacement
pump (109) on the tie rods (105).
NOTE: On Model 237283, reconnect the riser tube
(119) at either the elbow (120) or the connector (118).
3. Screw the nuts (108) onto the tie rods (105) and
torque to 81–89 N.m (60–66 ft-lb).
Continued on the next page.

308353 19
Service
Reconnecting the Displacement Pump
(continued)
4. Screw the coupling nut onto the motor shaft (W)
loosely. Hold the motor shaft flats with a wrench to
keep it from turning. Use an adjustable wrench to
tighten the coupling nut. Torque to 196–210 N.m
(145–155 ft-lb).
5. Reconnect all hoses. Reconnect the ground wire if
it was disconnected. Fill the packing nut (2) 1/3 full
of Graco Throat Seal Liquid or compatible solvent.
6. Turn on the air or hydraulic power supply. On
hydraulic pumps, open the hydraulic return line
valve first , then the supply line valve. Run the
pump slowly to ensure proper operation.
WARNING
To reduce the risk of serious injury whenever you
are instructed to relieve pressure, always follow the
Pressure Relief Procedure on page 12.
7. Before returning the pump to production, relieve
the pressure and retorque the packing nut (2) to
128–156 N.m (95–115 ft-lb).
05182B
Fig. 5
101
109
108
107
105
106
110
2
1
2
1
V
U
W
3
3
Model 236475 Shown
1
2
Torque to 128–156 N.m (95–115 ft-lb)
Torque to 196–210 N.m (145–155 ft-lb)
3Torque to 81–89 N.m (60–66 ft-lb)

20 308353
Service
DISPLACEMENT PUMP SERVICE
Disassembly
When disassembling the pump, lay out all the removed
parts in sequence, to ease reassembly.
NOTE: Packing Repair Kits are available. For the best
results, use all the new parts in the kit. Kit parts are
marked with an asterisk, for example (3*). These kits
can also be used to convert the pump to different
packing materials. Refer to pages 33 and 34.
1. Place the pump lengthwise in a large vise, with the
jaws on either the outlet housing (7) as shown in
Fig. 6, or on the cylinder (9) flats. Using the sup-
plied wrench (110), loosen, but do not remove, the
packing nut (2).
2. Apply a pipe wrench to the flats of the intake valve
(19). Unscrew the intake valve (19) from the intake
housing (18). Be careful to catch the intake ball
(17) as you remove the intake valve, so that it
does not fall and suffer damage. Remove the seal
(8) from the intake valve. Inspect the ball and the
seat (D) of the intake valve for wear or damage.
3. Apply a pipe wrench to the hex of the valve hous-
ing (18). The pump assembly may separate at joint
A or joint B.
CAUTION
To reduce the possibility of costly damage to the rod
(1) and cylinder (9), always use a rubber mallet to
drive the rod out of the cylinder. Never use a ham-
mer.
 If the assembly separates at joint A:
a. Unscrew the valve housing (18) from the
cylinder (hold cylinder flats with a 2–5/8 in.
wrench). Using a rubber mallet, drive the
displacement rod (1) and piston assembly out
of the outlet housing (7) and cylinder (9) until
the piston comes free. Pull the rod and piston
from the cylinder, being careful not to scratch
the parts.
b. Using a 2–5/8 in. wrench on the cylinder flats,
unscrew the cylinder (9) from the outlet hous-
ing (7). Remove the two seals (8) from the
cylinder. Shine a light into the cylinder (9) to
inspect the inner surface for scoring or wear.
Now go to step 4.
 If the assembly separates at joint B:
c. Unscrew the cylinder (9) and valve housing
(18) from the outlet housing (7). Gently pull the
cylinder and valve housing straight out of the
outlet housing; the displacement rod (1) and
piston assembly will come out with these
parts.
d. Place the valve housing (18) in the vise. Using
a 2–5/8 in. wrench on the cylinder flats, un-
screw the cylinder (9) from the housing. The
displacement rod (1) and piston assembly will
remain in the cylinder.
e. Using a rubber mallet, drive the displacement
rod (1) and piston assembly out of the cylinder
(9) until the piston comes free. Pull the rod and
piston from the cylinder, being careful not to
scratch the parts.
f. Remove the two seals (8) from the cylinder.
Shine a light into the cylinder (9) to inspect the
inner surface for scoring or wear. Now go to
step 4.
4. Place the flats of the piston seat housing (16) in a
vise, as shown in Fig. 7.
5. Using an adjustable wrench, unscrew the piston
ball housing (10) from the piston seat housing. Be
careful to catch the piston ball (11) as you sepa-
rate the piston seat housing and ball housing, so
that it does not fall and suffer damage.
6. Examine the displacement rod (1) for scratches or
other damage. Only if the rod needs replace-
ment, unscrew it from the piston ball housing (10),
using an adjustable wrench on the flats of the rod.
7. Remove the glands and v-packings (P) from the
piston seat housing (16). Inspect the ball (11), and
the seat (E) and guides (F) on the housing for
wear or damage. See Fig. 8.
8. Unscrew the packing nut (2) from the outlet hous-
ing (7). Remove the glands and v-packings (T).
See Fig. 8.
9. Clean all parts with a compatible solvent and
inspect them for wear or damage.