Failure Phenomena
1. Inadequate flow or no flow
Possible causes
a. Inlet and outlet valves are not open; inlet and outlet pipelines are blocked; or the impeller is blocked.
b. Motor runs in a wrong direction; motor runs with phase fault; or the rotary speed is slow.
c. The suction pipe leaks.
d. The pump is not filled with liquid; the pump chamber has air; or local high points of the suction pipeline have air.
e. Water is supplied insufficiently at the inlet; the suction head is too high; or the bottom valve leaks.
f. Pipe resistance is too high; or the pump model is improper.
 
Troubleshooting
a. Open the vale and remove the obstruction.
b. Adjust the motor running direction and tighten motor connection line.
c. Tighten nuts on all sealing surface and remove air.
d. Open the exhaust vale to drain the air. Drill air-bleed holes at local heights.
e. Stop the machine for inspection and adjustment (Such phenomenon occurs in inter-connected tap-water pipes and use with suction head).
f. Reduce pipe elbows, increase pipe diameter and re-elect pumps.
 
Failure Phenomena
2. Inadequate flow in water pump
Possible causes
a. Check according to causes specified in 1.
b. Pipeline or impeller passage is partially blocked; incrustation deposition or insufficient valve opening
c. Voltage is low.
d. Impeller is worn; flow, head or efficiency declines.
 
Troubleshooting
a. Troubleshoot according to 1.
b. Remove obstruction and readjust the valve opening.
c. Stabilize the voltage.
d. Replace the impeller.
 
Failure Phenomena
Possible causes
a. Piping support is instable. Foundation is loose.
b. Liquid is mixed with gas.
c. Cavitation occurs or flow is too large.
d. Bearing is damaged.
e. Motor is overload and runs with heat.
 
Troubleshooting
a. Stabilize the pipeline and reinforce the foundation.
b. Exhaust gas.
c. Increase inlet pressure and reduce the flow.
d. Replace the bearing.
e. Adjust according to 4.