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11
R
GB
Problem
A. Spitting gun
B. Gun will not shut off
C. Gun does not spray
Problem
A. Pump delivers on upstroke
only or goes up slowly and
down fast (commonly called
downstroke dive)
B. Pump delivers on down stroke
only or goes up fast and down
slowly
C. Pump moves up and down
fast, delivering material
D. Pump moves up and down
slowly when spray gun is shut
off
E. Not enough fluid pressure at
gun
F. Pump chatters on up or down
stroke
Cause
1. Air in system
2. Dirty gun
3. Needle assembly out of adjustment
4. Broken or chipped seat
1. Worn or broken needle & seat
2. Needle assembly out of adjustment
3. Dirty gun
1. No paint
2. Plugged filter or tip
3. Broken needle in gun
Cause
1. Lower foot valve ball is not seating due to
trash or wear
2. Material too viscous to siphon.
3. Air leaking in on siphon side or damaged
siphon hose. Siphon may be too small for
heavy material.
1. Upper ball is not seating due to trash or
wear
2. Lower packing set is worn
1. Material container is empty or material is
too thick to flow through siphon hose
2. Bottom ball stuck to foot valve seat
3. Siphon hose is kinked or loose
1. Loose connections. Bleed valve is open
partially or bleed valve is worn. Lower
packing seat is worn.
2. Upper and/or lower ball not seating
1. Spray tip is worn
2. Outlet filter or gun filter is clogged
3. Low voltage and/or inadequate amperage
4. Hose size or length is too small or too long
1. Solvent has caused upper packing to swell
Solution
1. Inspect connections for air leaks.
2. Disassemble and clean.
3. Inspect and adjust.
4. Inspect and replace.
1. Replace.
2. Adjust.
3. Clean.
1. Check fluid supply.
2. Clean.
3. Replace.
Solution
1. Remove foot valve assembly. Clean and inspect.
Test foot valve by filling with water; if ball fails to seal
the seat, replace ball.
2. Thin material — contact manufacturer for proper
thinning procedures.
3. Tighten all connections between pump and paint
container. If damaged, replace. Switch to larger
diameter siphon set.
1. Check upper seat and ball with water. If ball fails to
seal, replace seat.
2. Replace packing set if worn.
1. Refill with new material. If too thick, remove siphon
hose, immerse fluid section in material, and start
pump to prime. Add thinner to material. Change to
bigger siphon set. Open bleed valve to remove air
and restart pump.
2. Remove foot valve. Clean ball and seat.
3. Straighten.
1. Check all connections between pump and gun.
Tighten as necessary. If material is flowing from
bleed hose, close bleed valve or replace, if
necessary. Should none of the above be evident,
replace lower packing.
2. Reseat balls by cleaning.
1. Replace.
2. Clean or replace filter.
3. Check electrical service. Correct as required.
4. Increase hose size to minimize pressure drop
through hose and/or reduce hose length.
1. Replace packing.
Troubleshooting
Airless Gun
Fluid Section