Parker PV Series - Pump does not compensate; Pump does not upstroke, sticks at zero displacement.; Compensator is unstable

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Parker Hannifin Manufacturing Germany GmbH & Co. KG
Pump & Motor Division Europe
Chemnitz, Germany
Electro hydraulic proportional controls version 45 for
axial piston pumps, PV series
Bulletin MSG30-3254-INST/UK
Installation and setup manual
Trouble shooting guide
Pump does not build up pressure, but delivers full flow at low pressure
reason
solution
Horse power compensator setting changed.
Check setting of horse power compensator and correct it, if required.
reason
solution
Proportional displacement control is not connected as required.
Check wiring; connect according to installation manual for electronic module.
reason
solution
Displacement transducer (LVDT) adjustement changed.
Correct zero setting at displacement transducer.
reason
solution
Electronic module has no supply power.
Make sure module is powered with 22 - 36 V DC.
reason
solution
Cylinder block lifts from valve plate due to excessive wear.
Send pump to factory for service.
Pump does not compensate
reason
solution
No pressure pilot valve connected to compensator or valve is blocked.
Connect pressure pilot valve to compensator, make sure valve opens as required.
reason
solution
No or too low pressure at pump outlet port.
Pump outlet pressure must be at least 15 bar, because otherwise the bias spring
in the pump cannot be compressed.
Pump does not upstroke, sticks at zero displacement.
reason
solution
Compensator is blocked due to contamination.
Clean hydraulic fluid, clean compensator valve.
reason
solution
Cable to LVDT or proportional solenoid is interrupted
Check wiring and make sure cable is ok. Replace if necessary.
Compensator is unstable
reason
solution
Compenstor spool is sticking due to contamination of hydraulic fluid.
Clean hydraulic system, clean compensator valve.
reason
solution
Compensator dierential pressure changed (too low or too high)
Adjust compensator differential pressure to required setting.
reason
solution
Wrong pilot orifice or pressure pilot valve improperly selected.
Select pilot orifice and pressure pilot valve as recommended.
reason
solution
Dynamic critical system, e. g.: pressure compensator combined with pressure
reducing valve, load sensing (flow) compensator combined with flow control valve.
use remote pressure compensator instead of standard pressure compensator.