Troubleshooting - General
3A9121A
21
Troubleshooting - General
NOTE:
To find parts lists for the parts identified in the
troubleshooting tables, see page numbers listed in the
table below.
2. Check all possible causes and problems before
disassembling pump.
* To determine if fluid hose or gun is obstructed,
follow the
Disconnect fluid hose and place a container at
pump fluid outlet to catch any fluid. Turn on air
power just enough to start pump. If pump starts,
the obstruction is in fluid hose or gun.
Problem
Cause
Solution
Does not operate.
Valve closed or clogged.
Clear air line; increase air supply.
Check that valves are open.
Fluid hose or gun obstructed.
Clean hose or gun.*
Dried fluid on displacement rod.
Clean rod; always stop pump at bottom
of stroke; keep wet-cup filled with
compatible solvent.
Air motor parts dirty, worn, or damaged. Clean or repair air motor.
Output low on both strokes.
Air line restricted or air supply
inadequate. Valves closed or clogged.
Clear air line; increase air supply.
Check that valves are open.
Fluid hose/gun obstructed; hose ID too
small.
Clear hose or gun*; use hose with larger
ID.
Air motor icing.
Open De-Ice control.
Output low on down stroke.
Open or worn intake valve.
Clear or service intake valve.
High viscosity fluid.
Adjust intake spacers.
Output low on upstroke.
Open or worn piston valve or packings. Clear piston valve; replace packings.
Erratic accelerated speed.
Fluid supply exhausted, clogged
suction.
Refill supply and prime pump. Clean
suction tube.
High viscosity fluid.
Reduce viscosity; adjust intake
spacers.
Open or worn piston valve or packings. Clear piston valve; replace packings.
Open or worn intake valve.
Clear or service intake valve.
Runs sluggishly.
Possible icing.
Stop pump. Open De-Ice control.
Cycles or fails to hold
pressure at stall.
Worn check valves or seals.
Air bubbles in fluid.
Loose suction line.
Tighten. Use compatible liquid thread
sealant.
Poor finish or irregular spray
pattern.
Incorrect fluid pressure at gun.
See gun manual; read fluid
manufacturer’s recommendations.
Fluid is too thin or too thick.
Adjust fluid viscosity; read fluid
manufacturer’s recommendations.