Graco Inc 308741N dimensions Pressure Drop Chart, Inch 7.9 mm I.D. hose

Page 11

Setup

6. Adjust the Spray Pattern (continued)

NOTE:

DIf the fluid adjustment knob is turned in all the way the gun will emit only air.

DFor continuous spraying, turn the fluid adjustment knob (8) counterclockwise until no restriction of the trigger movement is felt. When the knob is turned out far enough, the trigger should be able to touch the gun handle when the gun is triggered. For the typical fluid adjustment knob setting, turn the knob out 1/2 turn more. This setting provides maximum fluid flow and prevents premature wear on the fluid nozzle.

E.Open the pattern adjustment valve (25) by turning the knob fully counterclockwise to achieve a full fan pattern.

25

Close

Open

(narrower

(wider

pattern)

pattern)

F

01997

Fig. 13

Pressure Drop Chart

5/16 inch (7.9 mm) I.D. hose

Recommended hose size to minimize excessive pressure drop. Expected pressure drops measured using 25 ft. (7.625 m) long hose, with gun triggered.

Air Regulator Pressure

Gun Inlet Pressure

Setting

 

psi (kPa, bar)

psi (kPa, bar)

 

 

18.5 (128, 1.3)

10 (70, 0.7)

 

 

34.0 (238, 2.3)

20 (140, 1.4)

 

 

48.0 (335, 3.3)

30 (210, 2.1)

 

 

62.5 (427, 4.3)

40 (280, 2.8)

 

 

76.5 (525, 5.3)

50 (345, 3.4)

 

 

90.5 (624, 6.3)

60 (410, 4.1)

 

 

Fig. 12

7040A

G. Test the spray pattern and atomization while hold-

ing the gun about 6 to 8 inches (150 to 200 mm)

from the test piece.

H. If the spray pattern is too wide with the pattern

adjustment knob (13a) turned fully counterclock-

wise, turn the pattern adjustment knob clockwise

F.Using the air pressure regulator (F), set the air supply pressure at about 50 psi (345 kPa, 3.4 bar). See the Pressure Drop Chart for regulator setting versus gun inlet pressure comparison.

If available, use the fluid manufacturer’s recom- mendations to set the air line pressure for a high volume, low pressure, spray gun application.

NOTE: Local laws may limit the maximum pres- sure to 10 psi (70 kPa, 0.7 bar) at the air cap for HVLP compliance. The accessory Air Cap Verifica- tion Kit is available to measure the atomizing pres- sure at the air cap.

 

until you have the desired pattern size.

 

NOTE: Turning the pattern adjustment knob fully

 

clockwise will produce a round pattern.

I.

Check the atomization quality again. Increase the

 

gun air supply pressure with the air pressure regu-

 

lator in 5 psi (34 kPa, 0.3 bar) increments until you

 

obtain the desired atomization.

J.

If after increasing the gun air supply pressure the

 

atomization is still unacceptable, try installing a

 

larger fluid nozzle size to reduce the fluid velocity.

 

Refer to Fig. 10. Repeat steps 6-E to 6-I until you

 

obtain the desired atomization.

308741 11

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Contents Table of Contents Instructions Parts List308741 SymbolsPressurized Equipment Hazard Hvlp Spray Gun Assemblies Selection ChartsOptional Hvlp Air Caps Hvlp Spray Gun and Pressure Cup AssembliesHvlp Spray Gun and Gravity Cup AssembliesAtomizing Air Pressure Air Flow and Atomizing PressureAir Flow Ventilate the Spray Booth Typical InstallationConnect the Fluid Hose SetupConnect the Air Line Relieve the Pressure Position the Air Cap Adjust the Spray PatternFlush the Spray Gun Fluid Velocity of Fluid Nozzles At the Same Flow Rate Inch 7.9 mm I.D. hose Pressure Drop ChartAir Regulator Pressure Gun Inlet Pressure Setting Applying the Fluid Pressure Relief ProcedureOperation Do not immerse the gun in solvent Daily Gun Care, Flushing, and CleaningGeneral System Maintenance 7035A 7044A 7045A Lubricate Problem Cause Solution TroubleshootingFluid Packings Replacement ServiceItems Needed for Service 2b 2a Complete Gun Packing Replacement 20 or 25b 19 or 25a Service 308741 Item 13 includes item 13a Item 25 includes 25a-25d PartsItem 2 includes 2a-2b Item 12 Nozzle Needle Assy Part No to Pressure Feed Hvlp Spray Gun AssemblyDescription Qty Gun Needle Nozzle Kit7585A Gravity Feed Hvlp Spray Gun Assembly Accessories Quart Remote SST Pressure Cup Gravity CupGravity Cup Holder Bracket SST Pressure Cup Kit 239802 with single air regulatorCategory Data DimensionsTechnical Data 308741 Toll Free Graco Standard WarrantyGraco Information