Walrus Systemflo SLB-C Series Installation And Operation Manual page 10

SLB-C, SLB-S, SLB-N
Fault
The frequency of pump start-up is too high
Vibration and noise
Probable cause
Leakage in the foot valve, check valve or system
Ruptured membrane or no air pre-charge in surge tank
Cavitation
Make sure that pump and motor shafts are properly aligned
Worn motor bearings
Operation with frequency converter
Check vibration and noise damping devices
Possible Solution
Repair or replace the components
See relevant instructions in surge tank's manual
Reduce the required flow or improve the operating conditions
of the pump (suction conditions, head, flow resistance, liquid
temperature,viscosity,...etc.)
Adjust the pump and/or motor shafts
Replace the bearings or the motor
Consult a qualified engineer form the supplier of the frequency-
converter
Replace vibration & noise dampers, if worn