Graco Dura-Flo 750 User manual

308–417
Rev. C
Supersedes B
First choice when
quality counts. 
05241
05242
Model 236–459
Model 237–366
INSTRUCTIONS-PARTS LIST
INSTRUCTIONS
This manual contains important
warnings and information.
READ AND KEEP FOR REFERENCE.
CARBON STEEL
Dura-Flo 750 Pumps
With Severe-Duty Rod and Cylinder
Refer to page 2 for a List of Models and the T able of Contents.
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441
COPYRIGHT 1995, GRACO INC.
Graco Inc. is registered to I.S. EN ISO 9001

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List of Models
Pump Part No.
and Series Pump Model
Displacement
Pump Part No.
and Series Ratio
Maximum Fluid
W orking Pressure
Maximum Air
Input Pressure
236–459,
Series A
Kingt238–1 16,
Series A
68:1 42.2 MPa, 422 bar
(6120 psi)
0.63 MPa, 6.3 bar
(90 psi)
237–364,
Series A
Reduced Icing
Quiet King t
238–1 16,
Series A
68:1 42.2 MPa, 422 bar
(6120 psi)
0.63 MPa, 6.3 bar
(90 psi)
237–366,
Series A
Bulldogr 236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
237–582,
Series A
Reduced Icing
Quiet Bulldog r
236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
237–370,
Series A
Bulldogr
with riser tube
236–455,
Series A
33:1 22.8 MPa, 228 bar
(3300 psi)
0.7 MPa, 7 bar
(100 psi)
Table of Contents
Warnings 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation/Maintenance 10 . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting Chart 13. . . . . . . . . . . . . . . . . . . . . . . . .
Service 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Required Tools 14. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnecting the Displacement Pump 14. . . . . . .
Reconnecting the Displacement Pump 14. . . . . . .
Displacement Pump Service 16. . . . . . . . . . . . . . . .
Parts Drawings and Parts Lists 21. . . . . . . . . . . . . . . . . .
Pump Assemblies 21. . . . . . . . . . . . . . . . . . . . . . . . .
Displacement Pump 238–1 16 24. . . . . . . . . . . . . . .
Displacement Pump 236–455 26. . . . . . . . . . . . . . .
Technical Data 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensions 31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting Hole Layout 31. . . . . . . . . . . . . . . . . . . . . . . . . .
Warranty 32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Phone Number 32. . . . . . . . . . . . . . . . . . . . . . . . . .

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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 .
D
This equipment is for professional use only .
D
Read all instruction manuals, tags, and labels before operating the equipment.
D Use the equipment only for its intended purpose. If you are uncertain about usage, call your Graco
distributor.
D
Do not alter or modify this equipment. Use only genuine Graco parts and accessories.
D Check equipment daily . Repair or replace worn or damaged parts immediately .
D Do not exceed the maximum working pressure of the lowest rated system component. Refer to the
T echnical Data on pages 28 and 29 for the maximum working pressure of this equipment.
D Use 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.
D Do not use hoses to pull equipment.
D Route 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).
DW
ear hearing protection when operating this equipment.
D Do not lift pressurized equipment.
D Comply with all applicable local, state, and national fire, electrical, and safety regulations.

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WARNING
INJECTION HAZARD
Spray from the gun, hose 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 dif fuser 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 10 whenever you: are instructed to relieve pres -
sure; stop spraying; clean, check, or service the equipment; and install or clean the spray tip.
T ighten all fluid connections before operating the equipment.
 Check the hoses, tubes, and couplings daily . Replace worn, damaged, or loose parts immediately .
Permanently coupled hoses cannot be repaired; replace the entire hose.
 Use only Graco approved hoses. Do not remove any spring guard that is used to help protect the
hose from rupture caused by kinks or bends near the couplings.
MOVING P ARTS 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 10 to prevent the
equipment from starting unexpectedly
.

308-417 5
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 of f 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 .

6 308-417
Notes

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Installation
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
the Product Data Sheet, Form No. 305–722 for Bulldog
Pumps and Form No. 305–723 for King Pumps. If you
supply your own accessories, be sure they are ade -
quately 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 5.
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.
237–569 Ground Wire and Clamp.
Fig. 1
W
X
Y
Z
0864
2. Air and fluid hoses: use only electrically conductive
hoses.
3.
Air compressor: follow manufacturer ’ s recommen -
dations.
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.
T o 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.
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.
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 wall mount system. Pump
dimensions and the mounting hole layout are shown
on page 31.
If you are using a floor stand, refer to its separate
manual for installation and operation instructions.

 
Installation
System Accessories (continued)
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 of f. T rapped air can cause the pump to cycle
unexpectedly . Locate the valve close to the pump.
Order Part No. 107–141.
The fluid drain valve assists in relieving fluid pres -
sure in the displacement pump, hose, and gun.
T riggering the gun to relieve pressure may not be
suf ficient. Order Part No. 210–658.
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 above). Be sure the bleed valve is eas -
ily accessible from the pump, and is located
downstream 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
of f 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 of
f 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 .

308-417 9
Installation
04496
Fig. 2
KEY
APump
BWall
Bracket
C Pump Runaway V alve
D
Air Line Lubricator
EBleed-T ype Master Air V alve
(required, for pump)
F Pump Air Regulator
G Air Manifold
H Electrically Conductive
Air Supply Hose
J Air Line Filter
KBleed-T ype Master Air V alve
(for accessories)
L Fluid Filter
M Fluid Drain V alve (required)
N Electrically Conductive
Fluid Supply Hose
P Fluid Whip Hose
R Gun Swivel
S Airless Spray Gun
T Suction Kit
Y Ground Wire and Clamp
(required; see page 7
for installation instructions)
W Air Line Drain V alve
TYPICAL INSTALLATION
A
B
C
D
E
F
G
H
JK
M
N
P
Y
MAIN
AIR LINE
L
R
S
T
W

 
Operation/Maintenance
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 . T o reduce the risk of
an injury from injection, splashing fluid, or moving
parts, follow the Pressure Relief Procedure
whenever you:
D are instructed to relieve the pressure,
D stop spraying,
D check or service any of the system equipment,
D or install or clean the spray tips.
1. Lock the gun trigger safety .
2.
Shut of f the air supply to the pump.
3. Close the bleed-type master air valve (required in
your system).
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 (8) 1/3 full with
Graco Throat Seal Liquid (TSL) or compatible solvent.
See Fig. 3.
WARNING
T o 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 61–75 N S m (45–55 ft-lb) using the supplied
wrench (1 10). Do this whenever necessary . Do not
overtighten the packing nut.
05242
Fig. 3
110
8
1
Model
237–366
Shown
1Torque
to 61–75 N S m
(45–55 ft-lb)