Bulletin MSG30-3245-INST/UK 
Installation Manual
12
Parker Hannifin
Pump & Motor Division Europe
Chemnitz, Germany
Axial Piston Pump
Series PV, series 44 and higher
11. Trouble shooting guide
  Pump delivers no output flow.
  Drive motor does not turn.
  Reason  Motor is not connected correctly or one of the three phases has failed. Motor 
does not turn smoothly when pump is disconnected from pump.
  Solution  Check motor connections, check electrical power supply.
  Reason  Pump mechanically blocked. Motor turns smoothly when disconnected from 
pump.
  Solution  Send pump to factory for service.
  Drive motor only turns at slow speed.
  Reason  Motor is not selected properly. In star circuit not enough torque.
  Solution  Start pump at unloaded system. Use motor with more horse power.
  Reason  Pump is hydraulically blocked. No function of compensator, no pressure relief 
valve. Pump stops after e few turns.
  Solution  Check function of pump compensator (see below). Start pump at unloaded  
system.
  Drive motor turns, pump does not turn.
  Reason  Coupling is not or not correctly mounted.
  Solution  Check coupling assembly and correct it.
  Drive motor turns and pump turns.
  Reason  Wrong direction of rotation.
  Solution   Change direction of motor rotation.
  Reason  Fluid reservoir empty or not filled to level, suction line ends above fluid level.
  Solution  Fill reservoir to required level, if necessary increase suction pipe length.
  Reason  Suction line is blocked. E. g. by plugs, cleaning tissues, plastic-plugs. Ball valve in 
the  suction line closed. Suction filter blocked.
  Solution  Check suction line for free flow. Open valves in suction line. Valves should be 
equipped with electrical indicator. Check suction filter.
  Reason  Suction line not gas tight, pump gets air into suction port.
  Solution  Seal suction line against air ingression.
  Reason  Pressure line / system is not able to bleed air out.
 Solution  Unload pressure port, unload system before start, bleed air from pressure line.
  Pump does not build up pressure, but delivers full flow at low pressure.
  Reason  Standard pressure compensator is set to minimum pressure.
  Solution  Adjust compensator setting to desired pressure.
  Reason  Orifice in remote pressure compensator blocked.
 Solution  Make sure orifice Ø 0.8 mm in control spool is free and open.
  Reason  No pressure pilot valve connected to port P
R
.
  Solution  Install suitable pressure pilot valve and adjust it to the desired setting.
  Reason  Multiple pressure pilot selector valve is not energized. Pump works in stand-by.
  Solution  Energize selector valve solenoid.
  Reason  No load sensing line connected.
  Solution  Connect system load sensing port to compensator.
  Reason  Load sensing valve is closed or too small.
  Solution  Open load sensing valve, use larger valve size.
  Reason  Too much pressure drop between pump and load sensing valve.
  Solution  Make sure connection is wide enough and has not too much pressure drop.
  Reason  Differential pressure at compensator is adjusted improperly (too low).
  Solution  Check differential pressure adjustment and correct it as described above.