Graco 237503, 236770 User Manual
Instructions–Parts List
STAINLESS STEEL, WATERBASE COMPATIBLE
308401E
Back Pressure Regulator
For use in circulating systems to provide regulated back pressure to spray
gun(s) and to maintain proper system pressure. Model 237503 is the back
pressure regulator only. Model 236770 includes the gauge, tube, inlet adapter
and outlet swivel union.
300 psi (21 bar, 2.1 MPa) Maximum Inbound Pressure
180 psi (12.4 bar, 1.24 MPa) Maximum Regulated Pressure
Model 236770, Series B
Model 237503, Series B
Important Safety Instructions
Read all warnings and instructions in this manual.
Save these instructions.
Model 237503
Table of Contents
ENG
03963
Warnings 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operation 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Troubleshooting 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dimensions 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Technical Data 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessories 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warranty Back Cover. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Graco Information Back Cover. . . . . . . . . . . . . . . . . . . .
Model 236770
03505
INSTRUCTIONS
WARNING
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 component in your system. This
equipment has a 300 psi (21 bar, 2.1 MPa) maximum inbound pressure and a 180 psi (12.4 bar,
1.24 MPa) maximum regulated pressure.
D Follow the Pressure Relief Procedure on page 4 if the spray tip clogs and before cleaning,
checking or servicing the equipment.
D Do not stop or deflect leaks with your hand, body, glove or rag.
D Be sure all equipment safety devices are operating properly before each use.
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 Always wear protective eyewear, gloves, clothing and respirator as recommended by the fluid and
solvent manufacturer.
D Wear hearing protection when operating this equipment.
D Comply with all applicable local, state, and national fire, electrical, and safety regulations.
2 308401
KEY
A Fluid Supply Line
B Air Spray Gun
C Fluid Pressure Regulator
D Air Supply Line
E Adjusting Screw
Installation
F Back Pressure Regulator
(236770 shown)
G Fluid Return Line
H Ball Valve
A
B
C
G
Fig. 1
Installing the Back Pressure Regulator
CAUTION
Handle the back pressure valve with care to avoid
damaging the diaphragm.
Install the back pressure regulator in the spray gun
return line. See Fig. 1.
D
E
H
Connect the line to the inlet and outlet. Make sure the
flow direction agrees with the IN and OUT markings on
the bottom of the regulator body.
The back pressure regulator is adjustable to control
the fluid pressures in a circulating system from 5 to
180 psi (0.3 to 12.4 bar, .03 to 1.24 MPa).
If more than one spray station is used, install the back
pressure regulator in the fluid supply line after the last
station. This will help maintain proper circulating
pressures in the system.
F
03506
Operation
NOTE: The back pressure regulator controls pressure
ahead of its intake.
Turn the adjusting screw clockwise to increase pres-
sure and counterclockwise to decrease pressure.
Adjust the pump pressure and back pressure regulator
for the best spraying combination and for proper
circulation of fluid.
Flush the back pressure regulator with a compatible
solvent whenever the rest of the system or unit is
being flushed. Open the back pressure regulator
before flushing by turning the screw counterclockwise.
308401 3
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