DeVilbiss JGA-504 Service Bulletin Download Page 5

SB-2-259-B      Page 5

TROUBLESHOOTING

CONDITION

CAUSE

CORRECTION

Heavy top or

Horn holes plugged.

Clean.  Ream with nonmetallic point.

bottom pattern

Obstruction on top or bottom of fluid tip.

Clean.

Cap and/or tip seat dirty.

Clean.

Heavy right or

Left or right side horn holes plugged.

Clean.  Ream with nonmetallic point.

left side pattern

Dirt on left or right side of fluid tip.

Clean.

Remedies for the top-heavy, bottom-heavy,  right-heavy and left-heavy patterns:
1)  Determine if the obstruction is on the air cap or the fluid tip.  Do this by making  a test spray
pattern.  Then, rotate the cap one-half turn and spray another pattern. If the defect is inverted,
 obstruction is on the air cap.  Clean the air cap as previously instructed.
2)  If the defect is not inverted, it is on the fluid tip.  Check for a fine burr on the  edge of the fluid tip.
Remove with #600 wet or dry sand paper.
3)  Check for dried paint just inside the opening.  Remove paint by washing with solvent.

Heavy center pattern

Fluid pressure too high for atomization

Balance air and fluid pressure.

air (pressure feed).

Increase spray pattern width with spreader
adjustment valve.

Material flow exceeds air cap's capacity.

Thin or lower fluid flow.
Spreader adjustment valve set too low. Adjust.

Atomizing pressure too low.

Increase pressure.

Material too thick.

Thin to proper consistency.

Split spray pattern

Atomization air pressure too high.

Reduce at transformer or gun.

Fluid pressure too low (pressure feed only).

Increase fluid pressure (increases gun
handling speed).

Spreader adjusting valve set too high.

Adjust.

Jerky or fluttering spray

*Loose or damaged fluid tip/seat.

Tighten or replace.

Material level too low.

Refill.

Container tipped too far.

Hold more upright.

Obstruction in fluid passage.

Backflush with solvent.

Loose or broken fluid tube or fluid inlet nipple.

Tighten or replace.

Dry or loose fluid needle packing nut.

Lubricate or tighten.

Unable to get round spray

Spreader adjustment screw not seating properly.

Clean or replace.

Air cap retaining ring loose.

Tighten.

Will not spray

No air pressure at gun.

Check air supply and air lines.

Internal mix or pressure feed air cap and tip

Change to proper suction feed air cap and tip.

used with suction feed.
Fluid pressure too low with internal mix cap and

Increase fluid pressure at tank.

pressure tank.
Fluid needle adjusting screw not open enough.

Open fluid needle adjusting screw.

Fluid too heavy for suction feed.

Thin material or change to pressure feed.

Starved spray pattern

Inadequate material flow.

Back fluid adjusting screw out to first thread
or increase fluid pressure at tank.

Low atomization air pressure (suction feed)

Increase air pressure and rebalance gun.

Excessive overspray

Too much atomization air pressure.

Reduce pressure.

Gun too far from work surface.

Adjust to proper distance.

Improper stroking (arcing, gun motion too fast).

Move at moderate pace, parallel to work surface.

Excessive fog

Too much, or too fast-drying thinner.

Remix properly.

Too much atomization air pressure.

Reduce pressure.

Dry Spray

Air pressure too high.

Reduce air pressure.

Gun tip too far from work surface.

Adjust to proper distance.

Gun motion too fast.

Slow down.

Gun out of adjustment.

Adjust.

Fluid leaking from

Packing nut loose.

Tighten, do not bind needle.

packing nut

Packing worn or dry.

Replace or lubricate.

Paint bubbles in cup.

Fluid tip not tight.

Tighten tip to 15-20 ft. lbs.

*Most common problem.

Summary of Contents for JGA-504

Page 1: ... 1 1 trichloroethane andmethylenechloride canchemi cally react with the aluminum in this gun and cause an explosion hazard Read the label or data sheet for the material you intend to spray Do not use spray materials containing these solvents with this spray gun Important This gun may be used with most common coating and finishing materials Itisdesignedforusewithmildly corrosive and nonabrasive mat...

Page 2: ...th the require ments of NFPA 33 Chapter 15 Users must comply with all local and national codes of practice and insurance company require ments governing ventilation fire precautions operation main tenance and housekeeping These are OSHA Sections 1910 94 and 1910 107 and NFPA 33 Cumulative Trauma Use of hand tools may cause cumulative Pain tingling or numbness in the shoulder forearm wrist Disorder...

Page 3: ... nut and remove 4 Remove old packing 5 Assemble packing nut to needle 6 Assemble packing in order shown to needle 7 Insert needle all the way into gun body seating in tip 8 Install needle spring and adjusting knob 9 Thread packing nut into gun body 10 Tighten packing nut in equal increments no more than 1 6 turn at a time 11 After each adjustment pull needle open and observe needle closure 12 If n...

Page 4: ...No Description Req 22 U Cup Seal 1 23 Washer 1 24 Snap Ring 1 25 JGS 449 1 Air Valve Assembly 1 26 P MB 51 Air Inlet Nipple 1 1 4 NPS M 27 Trigger Stud Screw 1 28 Trigger Stud 1 29 JGS 478 Stud and Screw Kit 1 30 Trigger 1 31 JGS 477 1 Trigger Stud Screw Kit 1 32 Fluid Inlet Gasket PTFE 1 33 Locknut 1 34 Fluid Inlet Adapter 1 35 JGA 4042 Fluid Inlet Gasket Nut Kit 1 36 Retaining Clip 1 37 Seal 1 3...

Page 5: ...damaged fluid tip seat Tighten or replace Material level too low Refill Container tipped too far Hold more upright Obstruction in fluid passage Backflush with solvent Loose or broken fluid tube or fluid inlet nipple Tighten or replace Dry or loose fluid needle packing nut Lubricate or tighten Unable to get round spray Spreader adjustment screw not seating properly Clean or replace Air cap retainin...

Page 6: ...o slow proper gun technique Thin sandy coarse finish Gun too far from surface Check distance Normally approx 6 8 drying before it flows out Too much air pressure Reduce air pressure and check spray pattern Improper thinner being used Follow paint manufacturer smixing instructions Thick dimpled finish Gun too close to surface Check distance Normally approx 6 8 orange peel Too much material coarsely...

Page 7: ...no silicone or petroleum distil latestocontaminate paint MSDS avail able upon request 192212 Professional Spray Gun Cleaning Kit Contains six precision tools designed to effectively clean all DeVilbiss Binks Finishline and other brand spray guns 192218 Scrubs Hand Cleaner Towels P r e m o i s t e n e d waterless hand cleaner towels for painters bodymen and mechanics JGA 156 K10 Spring Clip Joins a...

Page 8: ...ilbiss Automotive Refinishing DeVilbiss has authorized distributors throughout the world For equipment parts and service check the Yellow Pages under Automotive Body Shop Equipment and Supplies For technical assistance see listing below U S Canada Customer Service Office 1724 Indian Wood Circle Suite J K Maumee OH 43537 Toll Free Telephone 1 800 445 3988 U S A and Canada only Toll Free Fax 1 800 4...

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