NU.ER.T. - Rotary Vane Pumps

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Pump's frequently asked questions

Pump does not reach nominal flow rate or an adequate pressure

  • If equipment is provided with filter at pump inlet, make sure that it is not clogged or inadequate.
  • Make sure that pump end plate has not been slack.
  • Make sure that bypass valve and its seat are undamaged and clean.
  • Check that inlet and outlet nipples are not clogged.
  • Make sure that piston of bypass nut is not blocked.
  • If, after all these operations, pump does not work yet, get in touch with our company or a service center.

Pump is noisy or manometer vibrates

  • Verify that water reaching pump is sufficient. Exclude any throat or obstacle.
  • Verify that bypass nut is not slack and that its gasket is not damaged.
  • Verify integrity and cleanness of O-RING assembled on bypass piston.
  • For models with filter, check that PR 2042 nut is well tight and that its O-RING (PR 2073) is undamaged.
  • Make sure that inlet filter is not clogged.
  • Check that pump does not suck up air. For this purpose, make sure that inlet pipes and nipples are undamaged and well tight.
  • Verify that V-band clamp is not slack or too closed. Line up again pump and block it properly.
  • Check coupling between motor and pump. There must be no dents on the contact surface. If there should be, eliminate them.
  • Verify concentricity between motor axis and fixing seat of the pump.
  • If you made use of potential abrasive liquids or with suspended solids, get in touch with our company or with a service center.
  • If you pour off carbonated liquids, this might cause noise.

Pump is leaking

  • If it leaks from peephole, replace pump and get in touch with our company or a service center.
  • If it leaks from bypass nut, make sure that it is well tight. If necessary replace gasket (PR 2072).
  • If it leaks from pressure adjustment screw, disassemble nut and replace piston O-RING, lubricate it with vaseline oil.
  • Pump model with filter: if it leaks from PR 2042 nut, make sure it is well tight and, if necessary, disassemble it and replace its O-RING (PR 2073).

Pump jams or turns in an irregular way

  • Make sure that motor axis and pump axis are perfectly aligned.
  • Suppose there is limestone inside the pump, disassemble pump from the motor and wash it internally using an anti-limestone, then execute some manual rotations till it turns without difficulty, then assemble it again.
  • Owing to materials dimensional shrinkage, due to low temperatures, pump might block. For this reason avoid to make it work at temperatures lower than 8°C. If you place it in cold rooms, before making it work, make sure it turns freely.

Motor is stalling or works in an irregular way

  • Verify that the voltage of the motor is correct and that it is not defective.
  • If the pump is blocked or it does not turn freely, maybe there is too much limestone or pump and motor are misaligned. In the first case, remove pump from motor and eliminate limestone with an additive. In the second case, replace motor with another one having an axis with a radial run-out and perpendicularity error of 0.1 mm maximum compared to fixing seat of the pump.


Before you try to work on the pump or the systems, turn the motor off and disconnect the power to the motor.