If the paddle wheel does not rotate, stop the pump immediately. Check the operation of the solenoid. If the
solenoid is operating correctly, check the oil lines for blockage.
Note: Momentarily jog the pump for at least two revolutions.
Jog the motor momentarily while observing pump rotation. If the pump does not rotate in a clockwise direction,
interchange any two of the three-phase leads.
Ensure the oil solenoid valve operates properly by checking the oil flow indicator. The paddle wheel should rotate
after system pressure is below 600 mm Hg (6 inch Hg at inlet). Solenoid operation is also apparent as it will create a
magnetic field and become warm.
The oil solenoid valve is normally closed and must be energized when the pump starts.
The pressure differential between the oil reservoir (atmospheric pressure) and the pump cavity (vacuum) forces the
oil to the bearings and into the pump cavity. The oil lubricates the moving parts and also creates an oil seal.
Oil starts to flow at 800 mbar (600 Torr). At 533 mbar (400 Torr) the flow is approximately 50 %. From 133 mbar (100
Torr) to blank-off, flow is 100 %.
Note: 533 mbar (400 Torr) must be reached within 10 minutes or a force-feed lubrication system is required to
provide adequate oil flow to the pump cavity.
4.2 Pump start
Do not start the pump if the oil temperature is below 13 °C (55 °F).
Note: New belts usually lose some tension during initial operation and should be re-checked during the first few
days of operation. Always tension the belts according to the specifications of the belt manufacturer.
Excessive tension can induce unnecessary loading on the blower bearings, while extreme over-tensioning
may cause the shaft to break as a result of fatigue.
1. Turn on the cooling water supply.
2. Ensure the equipment being evacuated is properly cleaned and all vacuum breaks are closed.
3. Depress the START button and check the solenoid valve for proper operation.
4. Open the pump inlet valve.
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