DeVillbiss Air Power Company SB-2-540 operation manual Troubleshooting Condition Cause Correction

		SB-2-540	Page 7
TROUBLESHOOTING
CONDITION	CAUSE	CORRECTION
Heavy top or	Horn holes plugged.	Clean. Ream with non-metallic point.
bottom pattern	Obstruction on top or bottom of fluid tip.	Clean.
	Cap and/or tip seat dirty.	Clean.
Heavy right or left	Left or right side horn holes plugged.	Clean. Ream with non-metallic point.
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 by washing with solvent.
Heavy center pattern	Fluid flow too high for atomization air.	Balance air pressure and fluid flow. 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 flow too low.	Increase fluid flow (increases gun handling
	Spreader adjusting valve set too high.	speed).
		Adjust.
Jerky or fluttering spray	*Loose or damaged fluid tip/seat.	Tighten or replace.
	Baffle seal installed incorrectly.	Install per directions.
	Material level too low.	Refill.
	Container tipped too far.	Hold more upright.
	Obstruction in fluid passage.	Backflush with solvent.
	Dry or loose fluid needle packing nut.	Lubricate or tighten.
Unable to get round spray	Spreader adjustment screw not seating	Clean or replace.
	properly.
	Air cap retaining ring loose.	Tighten.
Will not spray	No air pressure at gun.	Check air supply and air lines, blow out gun
		air passages.
	Fluid needle adjusting screw not open	Open fluid needle adjusting screw.
	enough.
	Fluid too heavy for gravity feed.	Thin material and/or change to larger tip size.
Paint bubbles in cup	Fluid tip not tight.	Tighten tip to 12-15 ft-lbs.
Fluid leaking or dripping from	Cup lid loose.	Push in or tighten lid.
cup lid	Dirty threads on cup or lid.	Clean.
	Cracked cup or lid.	Replace cup and lid.
Starved spray pattern	Inadequate material flow.	Back fluid adjusting screw out to first thread,
		or change to larger tip size.
	Low atomization air pressure.	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	Move at moderate pace, parallel to work
	fast).	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	Packing nut loose.	Tighten, do not bind needle.
	Packing worn or dry.	Replace or lubricate.
Fluid leaking or dripping from	Packing nut too tight.	Adjust.
front of gun	Dry packing.	Lubricate.
	Fluid tip or needle worn or damaged.	Replace tip and needle.
	Foreign matter in tip.	Clean.
	Fluid needle spring broken.	Replace.
	Wrong size needle or tip.	Replace.

*Most common problem.