DeVilbiss FLG-691, Service Bulletin

Page: 5 / 8

SB-2-614-C Page 5
TROUBLESHOOTING
CONDITION CAUSE CORRECTION
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
Horn holes plugged.
Obstruction on top or bottom of fluid tip.
Cap and/or tip seat dirty.
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.
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.
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.
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.
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.
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.
*Most common problem.