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Troubleshooting
3A2012J 41
* To determine if fluid hose or gun is obstructed, follow Pressure Relief Procedure and Shutdown, page 24. Dis-
connect 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.
** The runaway solenoid can still be actuated if the Runaway Error is not displayed. Also, disabling the runaway
monitor will not retract the solenoid.
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. Clear hose or gun*.
Air motor icing. See air motor manual for instructions.
Exhausted fluid supply. Refill and prime pump.
Worn piston packings. Replace.
Open or worn intake valve. Clear or service intake valve.
Pump output low on
only one stroke.
Held open or worn ball check valves. Check and repair.
Worn piston packings. Replace.
No output. Improperly installed ball check valves. Check and repair.
Pump operates errati-
cally.
Exhausted fluid supply. Refill and reprime pump.
Held open or worn ball check valves. Check and repair.
Worn piston packing. Replace.
Suction tube too restrictive, causing pump to cavi-
tate
Use larger diameter tube
Erratic accelerated
speed.
Fluid supply exhausted, clogged suction. Refill supply and prime pump. Clean suction tube.
High viscosity fluid. Reduce viscosity; increase fluid temperature,
reduce flow rate by using smaller tip.
Open or worn piston valve or seal. Clear piston valve; replace seal.
Open or worn intake valve. Clear or service intake valve.
Runs sluggishly. Possible icing. See air motor manual for instructions.
Filler material clumping causing extra friction on
rods and seals.
Flush pump and replace packings.
Cycles or fails to hold
pressure at stall.
Worn check valves or seals. Service lower. See lower manual for instructions.
Air bubbles in fluid. Loose suction line. Tighten. Use compatible liquid thread sealant or
PTFE tape on connections.
Poor finish or irregular
spray pattern.
Incorrect fluid pressure at gun. See gun manual; read fluid manufacturer’s recom-
mendations.
Fluid is too thin or too thick. Adjust fluid viscosity; read fluid manufacturer’s rec-
ommendations.
Dirty, worn, or damaged spray gun. Service spray gun. See spray gun manual.
Difficulty priming Inlet ball stuck to seat Tap pump with hammer to dislodge.
Remove inlet ball, flush dried material, re-install
inlet ball.
Suction hose/strainer too restrictive or clogged Clean inlet strainer, shorten hose length and/or
increase hose diameter (especially cold or viscous
material.
Problem Cause Solution