Servicing Rotary Vane Type Vacuum Pump
1 Change the oil whenever there is a change in the performance of the pump. The oil should always be changed after pumping down a very dirty or burned out system. Always drain the pump while it’s still warm. Recharge the pump with the oil specified by the manufacturer.
2 Purging the pump periodically is helpful because it often cures many ills that develop as a result of poor maintenance:
a) Rotate the pump shaft by hand to make sure it’s free so the motor can operate the unit.
b) Run the pump with the intake closed until the pump is warm.
c) Shut it off, open the intake and drain the pump oil. With the drain open, the exhaust dome removed and the pump operating, slowly pour 2 ounces of the specified oil into the open intake fitting. As you hear the oil pass through the pump, cover the exhaust opening. This will cause the purging oil and any residual oil and sludge to flow rapidly out of the drain fitting. Repeat this step until all signs of contamination disappear.
d) When the purging is completed, close the drain fitting and, pouring through the exhaust dome hole, fill the pump with new, clean vacuum oil to the mid-point of the oil level gauge. Note: It’s normal for the oil level to rise somewhat as the pump warms up, but if the rise is excessive, the oil is contaminated.
e) If the pump is going to be out of service for some time after shutdown, drain the oil, purge the pump and fill it with new, clean oil. This will prevent corrosion by any contaminants that may be present in the old pump oil. Cover the intake and exhaust openings.