Instruction manual

4-7
4.2.3 Troubleshooting
Symptom Cause Countermeasure
Power failure or voltage drop
below 90 V.
Check the power supply. Pump does not rotate at all.
The breaker switches off
immediately. When turning
on the switch, pump buzzes
and does not start.
Oil highly viscous because the
ambient temperature is low (below
9 °C).
Close the suction port and turn
the switch on and off repeatedly
to repeat slight rotation or warm
the pump externally.
Air is leaking due to defective
vacuum piping.
Check for a leaky point and
repair as required.
The inside of vacuum pipe is
contaminated.
Degas the pipe.
Pipe is too thin or too long. Maximize the inner diameter of
pipe and minimize its length.
Vacuum degree cannot be
enhanced.
Oil is deteriorated. Replace oil.
Oil is inadequate. Add oil.
Air is leaking through the
upstream pipe.
Repair the leaky point.
Loud noise is emitted.
∗ Abnormal sound may occur for approx. 5 to 6 sec at start of
evacuation, but this does not indicate a fault.
Oil is leaking through the drain
valve (for VR16L).
Make sure the drain valve is
closed. If oil leaks through the
valve is closed, replacement
with a new valve is required.
Oil is leaking through the drain
plug (for VR16L-K/N).
Retighten the plug. If oil still
leaks, replace the drain packing.
Oil is leaking.
Oil splashes through the exhaust
port.
Adjust oil level of replace the oil
mist trap (element).
Pump vibrates abnormally. Oil is highly viscous due to low
ambient temperature (below 9°C).
Warm the pump externally.
NOTICE: If the trouble cannot be remedied by the above procedures, contact your
dealer, because overhaul, cleaning or repair may be required at the specified
service shop.