DeVilbiss JGA Maintenance And Troubleshooting Manual Download

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MAINTENANCE & TROUBLESHOOTING

PAGE 6

MAINTENANCE & TROUBLESHOOTING

PAGE 6

GUN FAULTS

Condition

Cause

Correction

Paint build-up on fluid tip

Fluid tip not fitted correctly in gun head

Fluid tip/needle leakage

Tighten to correct torque

Check for damage or blockage

Paint build-up on Air cap

Damaged air cap holes

Gradual build-up of bounce-back on gun
head

Replace with new Air cap

Thorougly clean

Slow fluid leak from needle packing

Fluid needle packing worn or loose

Tighten or replace as necessary

Air valve sluggish or slow to turn
on/off when trigger is
pulled/released

Air valve stem bent

Contamination on air valve stem

Replace damaged component

Remove and clean

Air leak from around air valve stem

Air valve seal damaged or missing

Replace

Air valve will not operate (air valve
stem will not fully slide into valve
body) when trigger is pulled

Air valve stem bent

Contamination on air valve stem

Remove air valve and replace damaged air
valve stem

Remove air valve and thoroughly clean

Stiff trigger action

Air valve stem bent

Contamination on air valve stem

Contamination on trigger bearing screw

Contamination on fluid needle shaft

Fluid needle packing too tight

Replace damaged component

Remove and clean

Loosen packing nut

Air leak from fluid needle exit point
in top of handle

Seal damaged or missing

Replace

Air cap retaining ring will not rotate

Contamination on retaining threads

Deformed or damaged retaining ring

Soak gun head in solvent to soften paint

Cut retaining ring off of gun (probably
replace retaining ring and baffle)

Unable to turn fan control knob on
top rear of gun

Internal O ring swollen or broken

Paint contamination on threads

Replace O ring

Remove and thoroughly clean

Unable to get round spray

Fluid tip or air baffle incorrectly fitted

Air baffle chinmey damaged

Remove, check components for damage
and refit correctly

Replace air baffle

Air leak from baffle seal

Baffle seal swollen or damaged

Replace

Unable to turn air control valve on
handle of gun

Internal O ring swollen or broken

Paint contamination on threads

Replace O ring

Remove and thoroughly clean

Summary of Contents for JGA

Page 1: ...cap horn hole dirty or damaged Test spray pattern rotate 180o and test again to isolate horn hole cause location Clean air cap thoroughly Replace air cap if necessary Fluid tip or cap dirty or damaged Test spray pattern rotate 180o and test again to isolate cause Clean both items thoroughly Replace Fluid tip or Air cap if necessary Single Split Pattern Centre Heavy Ellipse Too much air for fluid q...

Page 2: ...ful if inhaled or if there is contact with the skin Follow the requirements of the Material Safety Data Sheet supplied by your coating material manufacturer Adequate exhaust must be provided to keep the air free of accumulations of toxic materials Use a mask or respirator whenever there is a chance of inhaling sprayed materials This mask must be compatible with the material being sprayed and its c...

Page 3: ...anges with cap movement the condition is in the air cap Heavy centre pattern Too much material Material too thick Reduce fluid flow by turning fluid needle adjusting screw clockwise Reduce fluid pressure or increase atomisation pressure Thin Intermittent or fluttering spray fan Loose fluid tip Fluid tip not seated correctly in gun head Gun with cup tipped at excessive angle Obstructed fluid passag...

Page 4: ...aterial too thin Gun tilted on an angle Adjust gun or reduce fluid pressure Mix properly or apply light coats Hold gun at right angle to work and adapt to proper gun technique Thin sandy coarse finish drying before it flows out Gun too far from surface Too much air pressure Improper thinner being used Check distance normally 6 8 Reduce air pressure and check spray pattern Follow paint manufacturer...

Page 5: ...MAINTENANCE TROUBLESHOOTING PAGE 4 MAINTENANCE TROUBLESHOOTING PAGE 4 ...

Page 6: ...alve and thorougly clean valve shaft and seating surfaces Replace A Gun spits paint when triggering on due to paint build up inside air cap between spraying operations Fluid tip not fitted correctly in gun head Fluid tip needle leakage Tighten to correct torque Check for damage or blockage B Slow fluid leak from fluid tip and needle seat Fluid Tip internal seat scored damaged or worn Fluid needle ...

Page 7: ...lve and thoroughly clean E Stiff trigger action Air valve stem bent Contamination on air valve stem Contamination on trigger bearing screw Contamination on fluid needle shaft Fluid needle packing too tight Replace damaged component Remove and clean Remove and clean Remove and clean Loosen packing nut F Air leak from fluid needle exit point in top of handle Seal damaged or missing Replace G Air cap...

Page 8: ...ent and air discharge is clear Allow air to dry passages and then shut air valve at hose cleaner Repeat with hose to cup or tank connected to hose cleaner Lid on cup or tank should be set to one side of the shell or on a waste container Note This cannot be done with a pump Pump must be run with proper solvent to clean Clean inside of container and lid Wipe down gun with cleaning solvent dampened r...

Page 9: ...air cap retaining ring and gun air baffle threads are free from damage a smear of Vaseline on the threads will help prevent binding 2 Check air baffle seal is not leaking air badly or visibly damaged Replace if necessary 3 Apply smear of Vaseline to needle shaft front end for smooth operation 4 Apply Vaseline to needle shaft rear end and needle spring to aid corrosion and contamination resistance ...

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DeVilbiss JGA, Maintenance And Troubleshooting Manual

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