© Edwards Limited 2016. All rights reserved. Page 19
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Maintenance
LRP200000201 Issue A
If the abnormal noise continues or increases, the pump is operating under cavitation conditions, immediately
shut down the pumping system and investigate the cause. Possible causes of cavitation are:
Operation with insufficient non-condensible gas load. Check the process conditions and consult Edwards
Applications Engineers for advice.
Operation with insufficient seal liquid flow. Slowly open the seal liquid regulating valve until the
abnormal noise stops. Refer to manufacturer's instructions listed in Section 1.2.7 for the design seal
liquid flow rate.
Operation with excessive seal liquid temperature. Check seal liquid outlet temperature. Check seal liquid
outlet temperature as indicated on the seal liquid temperature indicator and the cooling liquid inlet
temperature inlet temperature. If the temperature difference exceeds 5 °C, check the cooling liquid
circuit.
5.5 Rotate the standby liquid ring pump drive shaft
Edwards preferred method is to temporarily energise the drive motor starter every 10 days to allow the pump shaft
to turn through three or four rotations, to prevent pump seizure and grease migration.
5.6 Inspect the heat exchanger
Refer to the heat exchanger removal and refit instructions listed in Section 1.2.7, for removal and re-installation
instructions.
Refer to the heat exchanger instructions listed in Section 1.2.7, for inspection instructions.
5.7 Replenish the liquid ring pump bearings
Refer to the bareshaft liquid ring pump instructions listed in Section 1.2.7, for replenishment instructions.
1. Refer to the grease manufacturer's Safety Data Sheet (SDS).
2. Refer to the liquid ring pump installation drawing supplied with the pumping system for the locations of the
grease connections and bearing vents on the pump.
3. With the pump running use a suitable filling device to replenish each bearing with new grease. As new grease is
forced in, old grease and/or excess grease will be forced out of the bearing vent.
Wipe away any grease from the bearing grease connection and the vent.
A high quality lithium-based grease according to DIN 51825 K2K-30 must be used.
5.8 Fault finding
A guide to fault conditions and their possible causes is provided in Table 13 to assist in basic fault finding.
If a fault cannot be rectified when using this guide, call the supplier or Edwards for advice.
Do not mix different types of grease. Incompatible lubricants may cause bearing damage.
Grease can cause skin irritation and eye inflammation. Follow all safety precautions specified by
the manufacturer.
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