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How to use a Varnish Elimination Unit – VEU-F-AU

In this video, we will show you the major subsystems and components, how to install and change the filter elements and how to set up and operate the unit.

The unit has the following components: chiller unit, air blast cooler, 2 HEX plate coolers, OLF filter housing, pre-filter housing, pump/motor set, 4 lifting points and a control panel, including a variable speed drive and PLC.

Prior to starting the system, do the following: (remembering to always check the operating manual for more instructions and safety precautions).

  • Position the unit in place and apply the wheel brakes
  • Connect hoses to the inlet and outlet port. It’s important to only use the hoses that are supplied with the unit, as these are designed specifically for the application.
  • Make sure that there is no obstruction in front, around or above the chiller, or the air blast cooler.
  • Check the chiller tank level, and top up. The chiller tank should be filled with between 20% and 40% coolant, with the remaining volume being water. HYDAC recommends Fuchs, Maintain Fricofin XT as the coolant.
  • Install filter element in the OLF housing and pre-filter housing

In order to install the filter element in the OLF housing, do the following:

  • Isolate the inlet and outlet of the VEU from the oil supply
  • Undo the vent screw
  • It may be necessary to connect a drain hose to the ball valve before bleeding
  • Open the ball valve at the base and drain the oil. Close the ball valve once drained
  • Loosen the lower clamps. The housing may be split into 2 sections by loosening the upper clamp to reduce the weight on each section.
  • Lift up the housing cover
  • Remove the locking cap
  • Put element into position (this is the same procedure as for changing the element)
  • Replace locking cap once the filters are installed. This will ensure that the oil is filtered.
  • Replace housing cover, clamps and tighten vent screw.


To change the pre-filter element:

  • Unscrew the filter bowl
  • Fit the element
  • Screw the filter bowl fully and tighten to 40 Nm


  • After fitting the filter elements, plug the supply lead into a suitable, earthed and protected power outlet, ensuring the voltage and frequency are correct.

Start the VEU by completing the following steps:

  • Switch the Power Isolator to the ON position
  • The PLC is set to 15°C as the default, if it’s necessary press the configuration button and enter the OLF inlet temperature setpoint from 15 to 24°C. For normal operation, it’s not necessary to adjust the VSD or the PLC.
  • Press the start button

The VEU will now enter a calibration phase to determine the correct operating flow rate to achieve the temperature setpoint. This will take 2-3 minutes. As the VEU operates it will continue to monitor the Inlet Temperature of the OLF and adjust the flow rate accordingly.

Make sure that you monitor the coolant level of the chiller, and top up if necessary.

Vent the filter housing. In order to vent the housing, follow these steps:

  • Slowly undo the air bleed screw.
  • Bleed the filter housing through the air bleed screw until operating-fluid is seen
  • Tighten the air bleed screw.

Note that, if an “alarm or trip” message is present in the system operation panel, this will have to be reset before the system is ready to run, and here are some of the “alarms or trips” you may encounter:

  • ESTOP / FAN TRIP – emergency stop activation
  • INLET PRESSURE – a negative pressure is detected in the pressure line. This is a cavitation warning.
  • OLF FILTER CLOG REPLACE ELEMENT – OLF element 100% clogged
  • PRE-FILTER CLOG REPLACE ELEMENT – pre-filter element 100% clogged
  • OLF OVERPRESSURE – high pressure detected
  • WRONG PHASE DIR – chiller motor is rotating in the wrong direction. In this case, a qualified electrician must verify the phase rotation of the supply power.

To stop the unit, press the stop button and switch the power isolator to the OFF position.

Thanks for watching this video; you can find more information on our website www.hydac.com.au.

AUSTRALIA 1300 449 322

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