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Troubleshooting
28 310645S
Soft start won’t work/pump, always
loaded
Sensor is bad Change sensor, page 26
Air leak due to bad seal keeps valve
open
Replace seal
Normal soft start system delay Release trigger for 10-15 seconds.
Retry.
Switch is not operating properly Replace switch
Damaged solenoid valve on cylinder Check gun supply, hose and sprayer
for leaks
AIr leak
Material runs out of bottom of sprayer RotoFlex HD Pump worn out Replace hose.
Loose fittings Check and retighten all fittings.
No air from compressor Gun air valve closed Open gun air valve.
Gun needle plugged Clean needle and retry.
Lines not connected Check all quick disconnect connec-
tions to gun and hoses.
Damaged hose Replace hose.
Worn compressor Service compressor. Contact a quali-
fied Graco Service Center.
Speed of application too slow Material too thick Thin material.
Nozzle too small Change nozzles to a larger size. See
Operation Manual, Recommended
Nozzle Selection Chart, page 20.
Speed of application too slow (cont.) Flow control set too low Increase flow control setting
Plugged or dirty gun Relieve Pressure, page 7. Clean
gun.
Kinked hose Unkink hose.
Gun fluid flow adjustment set too low Increase flow adjustment with flow
adjustment nut.
Intermittent flow/sputtering or air in
material
Hopper connection not tight Check gasket. TIghten connection.
Debris in system Clean
Air quick disconnect does not stay
connected.
Dirty or corroded fitting Clean thoroughly. Soak in oil. Apply a
few drops of light oil.
Gun will not shut off Worn nozzle or needle. Relieve Pressure, page 7. Replace
worn parts.
Debris in needle passage Relieve Pressure, page 7. Clean.
Fluid leaking at Flow Adjustment Nut Damaged seal. Relieve Pressure, page 7. Replace
seal.
Needle adjustment won’t adjust Dirty threads Clean threads
Nozzle not on gun Put nozzle on gun
Flow nut set to maximum adjustment Turn flow nut adjustment the other
way
Problem Cause Solution