Jet JAT-501 Operations & Parts Manual page 10

Troubleshooting JAT-501 Mini HVLP Spray Gun
Any disassembly of the tool should be done by qualified service personnel. For problems not addressed
below, contact JET technical service at 800-274-6846.
Problem
Material bubbles or "boils"
in cup.
10 JAT-501 Mini HVLP Spray Gun
Possible cause
Correct normal pattern.
Dirty or damaged air cap.
Dirty or damaged fluid tip.
Pressure too high for material
viscosity being sprayed.
Dirty or distorted air horn holes.
One of the air horn holes
completely obstructed.
Air getting into paint stream.
Excess air blowing back into cup.
Remedy
No correction necessary.
Rotate air cap 180-degrees:
If pattern is following air cap,
problem is in air cap. Clean and
inspect. If pattern does not correct,
replacement is necessary.
If pattern is NOT following air cap,
problem is with fluid tip. Clean and
inspect tip for dried paint, dirt or
damage. If pattern does not
correct, replacement is necessary.
Reduce air pressure.
Increase material viscosity.
Pattern may also be corrected by
narrowing fan size with spray width
adjuster control knob.
Rotate air cap 180-degrees:
If pattern is following air cap,
problem is in air cap. Clean and
inspect the horn holes. If horn
holes are distorted, replacement is
necessary.
Check and tighten fluid needle
packing nut.
Tighten fluid nozzle.
Check fluid nozzle seat for
damage.
Check for poor gun-to-cup seating.
Check that cup is correctly
fastened on gun.
Tighten fluid nozzle.
Check fluid nozzle seat.
Check for damaged fluid seat on
nozzle or seat on gun head.