ALKOTA 5305A - Unloader Valve Troubleshooting; Unloader Valve Troubleshooting Guide

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Unloader Valve
Trouble Shooting
Valve, Unloader
p/n C07-04504M-A
Fuel Filter V04-00308
Troubleshooting
Trouble Possible Cause Remedy
Frequent valve recycles
Damaged check valve O-ring Remove and replace
Leaking connections Check or renew
Restricted bypass or too small
diameter of
the bypass hose
Clean or adapt
passage diameter
Valve does not reach
pressure
Piston O-rings worn out Remove and replace
Debris between seat and
shutter
Clean the seat
Seat worn out Remove and replace
Nozzle worn out Remove and replace
Incorrect choice of nozzle Fit with smaller nozzle
High pressure peaks at
gun closure
There is not a minimum of 5%
of total flow
discharged in bypass
Reset Correctly
Excessive flow in bypass
Change type of valve
or adjust passages
Adjustment with spring totally
compressed
Loosen adjustment
screw and eventually
fit with smaller nozzle
Valve does not
discharge
at low pressure at gun
closure
Jammed check valve Jammed check valve
Debris on check valve Clean
Maintenance Procedures
Every 400 working hours, check and lubricate the seals with water resistant
grease with water resistant grease.