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SB-2-168-N     Page  5

Balance air pressure and fluid flow. Increase 

spray pattern width with spreader adjustment 

valve.

Thin or lower fluid flow.

Adjust.

Increase pressure.

Thin to proper consistency.

Reduce at transformer or gun.

Increase fluid flow (increases gun handling 

speed).

Adjust.

Tighten or replace.

Install per directions.

Refill.

Hold more upright.

Backflush with solvent.

Lubricate or tighten.

Clean or replace.

Tighten.

Check air supply and air lines, blow out gun 

air passages.

Open fluid needle adjusting screw.

Thin material and/or change to larger tip size.

Tighten tip to 15-20 ft-lbs.

Push in or tighten lid.

Clean.

Replace cup and lid.

Back fluid adjusting screw out to first thread, 

or change to larger tip size.

Increase air pressure and rebalance gun.

Reduce pressure.

Adjust to proper distance.

Move at moderate pace, parallel to work 

surface.

Remix properly.

Reduce pressure.

Reduce air pressure.

Adjust to proper distance.

Slow down.

Adjust.

Tighten, do not bind needle.

Replace or lubricate.

Adjust.

Lubricate.

Replace tip and needle.

Clean.

Replace.

Replace.

Heavy top or 

bottom pattern

Heavy right or left 

side pattern

Heavy center pattern

Split spray pattern

Jerky or fluttering spray

Unable to get round spray

Will not spray

Paint bubbles in cup

Fluid leaking or dripping from 

cup lid

Starved spray pattern

Excessive overspray

Excessive fog

Dry spray 

Fluid leaking from packing nut

Fluid leaking or dripping from 

front of gun

TROUBLESHOOTING
 CONDITION 

CAUSE 

CORRECTION

Horn holes plugged.

Obstruction on top or bottom of fluid tip.

Cap and/or tip seat dirty.

Clean. Ream with non-metallic point.

Clean.

Clean.

Clean. Ream with non-metallic point.

Clean.

Fluid flow too high for atomization air.

Material flow exceeds air cap's capacity. 

Spreader adjustment valve set too low.

Atomizing pressure too low.

Material too thick.

Atomization air pressure too high.

Fluid flow too low. 

Spreader adjusting valve set too high.

*Loose or damaged fluid tip/seat.

Baffle seal installed incorrectly.

Material level too low.

Container tipped too far.

Obstruction in fluid passage.

Dry or loose fluid needle packing nut.

Spreader adjustment screw not seating 

properly.

Air cap retaining ring loose.

No air pressure at gun.

Fluid needle adjusting screw not open 

enough.

Fluid too heavy for gravity feed.

Fluid tip not tight.

Cup lid loose.

Dirty threads on cup or lid.

Cracked cup or lid.

Inadequate material flow.

Low atomization air pressure.

Too much atomization air pressure.

Gun too far from work surface.

Improper stroking (arcing, gun motion too 

fast).

Too much or too fast-drying thinner.

Too much atomization air pressure.

Air pressure too high.

Gun tip too far from work surface.

Gun motion too fast.

Gun out of adjustment.

Packing nut loose.

Packing worn or dry.

Packing nut too tight.

Dry packing.

Fluid tip or needle worn or damaged.

Foreign matter in tip.

Fluid needle spring broken.

Wrong size needle or tip.

Left or right side horn holes plugged.

Dirt on left or right side of fluid tip.

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 by washing with solvent.

*Most common problem.

Summary of Contents for GTI SB-2-168-N

Page 1: ...and HC 4719 Other types will not flow enough air for proper gun operation Note If an air adjusting valve is used at the gun inlet use DeVilbiss Model HAV 500 or HAV 511 Some competitive adjusting valv...

Page 2: ...rt 7 Working in cold temperatures CTD s can also be caused by such activities as sewing golf tennis and bowling to name a few Adequate exhaust must be provided to keep air free of accumulations of fla...

Page 3: ...s and packings Note When replacing the fluid tip or fluid needle replace both at the same time Using worn parts can cause fluid leakage See Chart 1 Also replace the needle packing at this time Lightly...

Page 4: ...Ref Replacement Parts No Part No Description Req 20 Air Valve 1 21 Air Valve Body 1 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...

Page 5: ...r atomization air Material flow exceeds air cap s capacity Spreader adjustment valve set too low Atomizing pressure too low Material too thick Atomization air pressure too high Fluid flow too low Spre...

Page 6: ...ng used Gun too close to surface Air pressure too low Improper thinner being used Material not properly mixed Surface rough oily dirty Tighten Replace cup gasket Clean Adjust gun or reduce fluid flow...

Page 7: ...e and as a daily quality control measure OMX 70 K48 Paint Cup Liner Kit Consists of 1 Piercing Tool 48 Disposable Liners 48 Drain Bushings Spray Gun Lube SSL 10 2 oz bottle Compatible with all paint m...

Page 8: ...w devilbiss com DeVilbiss Automotive Refinishing DeVilbiss has authorized distributors throughout the world For equipment parts and service check the Yellow Pages under Automotive Body Shop Equipment...

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