Ref 301085 Rev. B
02-22
PROBLEMS
PROBABLE CAUSES
SOLUTIONS
Frequent valve recycles
• Damaged check valve O-ring
• Leaking connections
• Restricted bypass or too small diameter of
the bypass hose
• Replace
• Check or renew
• Clean or adapt passage diameter
Valve does not reach
pressure
• Piston O-rings worn out
• Debris between seat and shutter
• Seat worn out
• Nozzle worn out
• Incorrect choice of nozzle
• Replace
• Clean the seat
• Replace
• Replace
• Fit with smaller nozzle
High pressure peaks at
gun closure
• There is not a minimum of 5% of total flow
discharged in bypass
• Excessive flow in bypass
• Adjustment with spring totally compressed
• Reset Correctly
• Change type of valve or adjust
passages
• Loosen adjustment screw and
eventually fit with smaller nozzle
Valve does not discharge
at low pressure at gun
closure
• Jammed check valve
• Debris on check valve
• Clean or replace
• Clean
TROUBLESHOOTING
GENERAL PUMP
1174 Northland Drive • Mendota Heights, MN 55120
Phone: 651.686.2199 • Fax: 800.535.1745 • e-mail: [email protected] • www.generalpump.com
ZH284KEZ
GENERAL PUMP
A member of the Interpump Group
Trapped Pressure Unloader Valve
MAINTENANCE
STANDARD: every 400 working hours, check and lubricate the seals with water resistant grease.
SPECIAL: every 800 working hours, check the wear of the seals and internal parts and, if necessary, replace with
original GP parts taking care, during installation, to lubricate with water resistant grease.
The manufacturer is not to be considered responsible for damage as a result from incorrect fitting and
maintenance.
WARNING: This product can expose you to chemicals including
lead, which is know to the state of California to cause cancer and
birth defects or other reproductive harm. For more information, go
to www.P65Warnings.ca.gov
