Dispense Valves - Graco PCF Instructions - Parts Manual

Dispense Valves

Problem
Valve not opening
Valve not shutting off
Sluggish open/close
Material leaks from back of valve
Air leaks from dispense valve
313377L
Cause
Air not getting to open port
No "Gun On" signal from automa-
tion unit
Air not getting to close port (except
AutoPlus valve)
"Gun On" signal from automation
unit is on
Air pressure low
Needle/seat worn
Pressurized material past the valve
shut-off is escaping
Shaft seal is worn
Loose air connections
Worn piston o-ring
Troubleshooting
Solution
Verify air pressure solenoid
Check input from automation unit
Verify air pressure to solenoid
Verify solenoid operation
Verify air line routing and connec-
tions
Check input from automation unit
Verify air pressure is above 60 psi
(0.4 MPa, 4 bar)
Rebuild valve; replace needle/seat
Reduce running pressure
Reduce nozzle length
Increase nozzle orifice size
Rebuild valve; replace seals
Check air connections; tighten if
necessary
Rebuild valve; replace piston o-ring
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