Graco Marine Instruments 236770 User Manual

Instructions–Parts List  
STAINLESS STEEL, WATERBASE COMPATIBLE  
308401E  
ENG  
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  
03963  
Table of Contents  
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2  
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3  
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3  
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4  
Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5  
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7  
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . Back Cover  
Model 236770  
Graco Information . . . . . . . . . . . . . . . . . . . . Back Cover  
03505  
 
Installation  
KEY  
A
B
C
D
E
Fluid Supply Line  
Air Spray Gun  
Fluid Pressure Regulator  
Air Supply Line  
Adjusting Screw  
F
Back Pressure Regulator  
(236770 shown)  
Fluid Return Line  
Ball Valve  
G
H
A
B
C
D
G
E
H
F
03506  
Fig. 1  
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.  
Installing the Back Pressure Regulator  
CAUTION  
Handle the back pressure valve with care to avoid  
damaging the diaphragm.  
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.  
Install the back pressure regulator in the spray gun  
return line. See Fig. 1.  
Operation  
NOTE: The back pressure regulator controls pressure  
ahead of its intake.  
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.  
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.  
308401 3  
 
Service  
3. Disassemble the regulator and clean it with a  
Pressure Relief Procedure  
suitable solvent. See the parts drawing, page 5.  
4. Carefully inspect the diaphragm (14) for cracks or  
WARNING  
other damage. Replace if necessary.  
PRESSURIZED EQUIPMENT HAZARD  
The system pressure must be manually relieved to  
prevent the system from starting or spraying acci-  
dentally. To reduce the risk of an injury from acci-  
dental spray from the gun, splashing fluid, or  
moving parts, follow the Pressure Relief Proce-  
dure whenever you:  
5. Check for chips or dirt that could puncture the  
diaphragm before assembling the regulator.  
6. Reassemble the diaphragm and related parts.  
Torque the cap nut (3) to 27 to 33 in-lb (3.1 to 3.7  
NSm).  
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 nozzle.  
7. Carefully inspect the seat (1) for damage, wear, or  
dirt. These things could cause the regulated pres-  
sure to creep. Replace the seat if necessary.  
8. Replace the seat gasket (6) when replacing the  
seat (1). Torque the seat to 70 to 80 in-lb (8 to 9  
NSm).  
1. Shut off the pump.  
2. Open the dispensing valve, if used.  
9. To remove or install the gauge on model 236770  
(20), use the wrench on the square portion of the  
gauge stud only.  
3. Open the fluid drain valve to relieve all fluid pres-  
sure, having a container ready to catch the drain-  
age.  
CAUTION  
Use thread sealer sparingly on the gauge’s male  
threads when installing it to avoid plugging the  
gauge.  
Service  
NOTE: Regular cleaning and inspection of the regula-  
tor, based upon the degree and kind of service, is  
essential.  
10. Lubricate the adjusting screw (15) threads.  
11. Assemble the remaining parts.  
1. Shut off the pump and open the back pressure  
regulator by turning the adjusting screw (15)  
counterclockwise until no spring pressure is felt.  
Relieve all air and fluid pressures in the system.  
12. Tighten the regulator cap (4) to 324 to 396 in-lb (37  
to 45 NSm).  
2. Remove the back pressure regulator from the fluid  
13. Reinstall the back pressure regulator in the fluid  
line.  
line.  
Troubleshooting  
Checking the Ball and Seat  
WARNING  
To reduce the risk of serious injury whenever you  
are instructed to relieve pressure, always follow the  
Pressure Relief Procedure above.  
The ball and seat may be checked for wear by closing  
the ball valve directly upstream of the back pressure  
regulator (Fig 1). When the ball valve is closed, the  
gauge pressure should drop slightly. If the pressure  
continues to drop, then the ball or seat is worn and  
needs to be replaced. Follow the preceding Service  
procedure to replace the worn ball or seat.  
4 308401  
 
Parts  
Stainless Steel Back Pressure Regulator –  
Model 236770, Series B Includes items 1 to 20  
Model 237503, Series B Includes items 1 to 15  
Ref.  
Ref.  
Qty. No.  
No.  
Part No. Description  
Part No. Description  
Qty.  
1n  
2n  
3
4
5
6n  
7n  
8
9
10  
11  
236893  
236894  
100529  
189815  
101976  
189817  
154789  
16C761  
157796  
160180  
100111  
SEAT, valve  
STEM, valve  
1
1
1
1
1
1
1
1
1
1
1
12  
13  
189816  
177432  
PLATE, backup  
PLATE, support, diaphragm  
DIAPHRAGM  
SCREW, adjusting, 1/2–20 x  
1–5/8 long  
UNION, adapter; 1/2–14 npt(m)  
x 3/8–18 npsm(f) swivel  
ADAPTER, inlet; 3/8–18  
npsm(m), 3/8–18 npt(m), 1/4–18  
npt(f)  
1
1
1
1
NUT, hex, cap; 5/16–18  
CAP, regulator, air  
WRENCH, Allen; 3/8  
GASKET, acetal  
GASKET, copper  
HOUSING, valve  
SPRING, compression  
PLATE, spring  
14n 177431  
15  
17  
18  
112844  
236892  
16C760  
1
1
NUT, lock; 1/2–20  
19  
187877  
TUBE, fluid gauge  
GAUGE, 0–300 psi  
(0–21 bar, 0–2.1 MPa)  
1
1
20n 187876  
n Keep these spare parts on hand to reduce down  
time.  
12  
20  
5
15  
11  
3
2
7
13  
14  
1
4
19  
18  
2
1
3
10  
9
6
8
1
Torque 324 to 396 in-lb (37 to 45 N.m)  
Torque 27 to 33 in-lb (3.1 to 3.7 N.m)  
2
3
17  
Torque 70 to 80 in-lb (8 to 9 N.m)  
03504  
308401 5  
 
Notes  
6 308401  
 
Dimensions  
Technical Data  
Maximum Inlet Pressure: . . . 300 psi (21 bar, 2.1 MPa)  
Regulated Pressure Range . . . . . . . . . . . . . . 5–180 psi  
(0.3–12.4 bar, .03–1.24 MPa)  
236770 Inlet Size . . . . . . . . . . . . . . . . . . . . . 3/8 npsm(m)  
236770 Outlet Size . . . . . . . . . . . . . . . . . . . . 3/8 npsm(f)  
237503 Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3/8 npt(f)  
237503 Outlet . . . . . . . . . . . . . . . . . . . . . . . . . . 1/2 npt(f)  
236770 Weight: . . . . . . . . . . . . . . . . . . . . . 3.5 lb (1.6 kg)  
237503 Weight: . . . . . . . . . . . . . . . . . . . . . 2.4 lb (1.1 kg)  
Wetted Parts:  
2.25 in. (57.2 mm  
diameter  
7.25 in.  
(184 mm)  
316 stainless steel, tungsten carbide (with nickel  
binder), acetal and PTFE  
3/8  
npsm(m)  
Inlet  
Maximum flow chart for 180 psi (12.4 bar, 1.24 MPa)  
inbound pressure and fluid viscosity of 65 cps  
Regulated Pressure  
50 psi (3.4 bar, 0.3 MPa) 4.7 gpm (17.8 lpm)  
100 psi (7 bar, 0.7 MPa)  
150 psi (10.3 bar,  
1.0 MPa)  
Maximum Flow Rate  
3/8  
npsm(f)  
Outlet  
4.3 gpm (16.3 lpm)  
3.7 gpm (12.9 lpm)  
Model 236770 shown  
03505  
Fig. 2  
Manual  
Change Summary  
Assembly  
Changed  
Part  
Status  
Ref. Part No. Name  
No.  
Accessories  
236770 and Old  
237503, to  
Series B  
20  
20  
187873  
187876  
Gauge  
Gauge  
New  
Air-Charge Conversion Kit 237448  
Maximum inbound pressure is increased to 300 psi (21  
bar, 2.1 MPa).  
Includes necessary parts to convert back pressure  
regulator from spring operated to air operated.  
308401 7  
 
The Graco Warranty and Disclaimers  
Graco warrants all equipment listed in this manual which is manufactured by Graco 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. With the exception of  
any special extended or limited warranty published by Graco, Graco will, for a period of twelve months from the date of sale, repair or  
replace any part of the equipment determined by Graco to be defective. 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 general wear and tear, or 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 of  
Graco equipment with structures, accessories, equipment or materials not supplied by Graco, or the improper design, manufacture,  
installation, operation or maintenance or 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 claimed defect. 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.  
Graco’s sole obligation and buyer’s sole remedy for any breach of warranty shall be as set forth above. The buyer agrees that no other  
remedy (including, but not limited to, incidental or consequential damages for lost profits, lost sales, injury to person or property, or any  
other incidental or consequential loss) shall be available. Any action for breach of warranty must be brought within two (2) years of the  
date of sale.  
GRACO MAKES NO WARRANTY, AND DISCLAIMS ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR  
A PARTICULAR PURPOSE IN CONNECTION WITH ACCESSORIES, EQUIPMENT, MATERIALS OR COMPONENTS SOLD BUT  
NOT MANUFACTURED BY GRACO. These items sold, but not manufactured by Graco (such as electric motors, gas engines,  
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.  
In no event will Graco be liable for indirect, incidental, special or consequential damages resulting from Graco supplying equipment  
hereunder, or the furnishing, performance, or use of any products or other goods sold hereto, whether due to a breach of contract,  
breach of warranty, the negligence of Graco, or otherwise.  
FOR GRACO CANADA CUSTOMERS  
The parties acknowledge that they have required that the present document, as well as all documents, notices and legal proceedings  
entered into, given or instituted pursuant hereto or relating directly or indirectly hereto, be drawn up in English. Les parties  
reconnaissent avoir convenu que la rédaction du présente document sera en Anglais, ainsi que tous documents, avis et procédures  
judiciaires exécutés, donnés ou intentés à la suite de ou en rapport, directement ou indirectement, avec les procédures concernées.  
Graco Information  
TO PLACE AN ORDER, contact your Graco distributor or call to identify the distributor closest to you:  
Phone: 612–623–6921 or Toll Free: 1–800–328–0211 Fax: 612–378–3505  
All written and visual data contained in this document reflects the latest product information available at the time of publication.  
Graco reserves the right to make changes at any time without notice.  
This manual contains English. MM 308401  
Graco Headquarters: Minneapolis  
International Offices: Belgium, China, Japan, Korea  
GRACO INC. P.O. BOX 1441 MINNEAPOLIS, MN 55440–1441  
Copyright 1994, Graco Inc. is registered to ISO 9001  
Revised 11/2009  
8 308401  
 

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