Goulds Pumps 3393 - IOM - Manual (Page 110)

Troubleshooting
Symptom Cause Remedy
The head is too low. The back pressure and discharge pres- Throttle the discharge valve.
sure are too low.
The speed is too low.
Increase the speed. Check the available
motor power.
Compare the speed of the motor with the
specified pump speed. See the rating
plate.
When you adjust the speed (frequency
transformet), check the reference value
settings.
The impeller diameter is too small. Use a larger impeller. Make sure to check
the available motor power.
The pump and/or pipes are not complete- Fill the pump and/or pipes with liquid.
ly filled with liquid.
Vent the pump and/or pipes.
The pump or suction/intake pipe are Clean the pipes.
blocked.
There is an air pocked in the pipeline.
Vent the pipeline.
Improve the path of the pipes.
The NPSH of the system is too low. Increase the liquid level.
Increase the suction pressure.
Reduce the resistance in the intake/suc-
tion pipe. Change the course and pipe
size, open the shutoff valves, and clean
the filters.
Air is being sucked into the pipes. Increase the liquid level.
Check that the suction pipe is vacuum-
tight.
Provide valves and fittings in the suction
pipe with water seal.
The direction of rotation is wrong. Change the motor rotation.
The inner components are suffering from Replace the worn parts.
wear.
The density and/or viscosity of the
Seek assistance.
pumped liquid is too high.
The head is too high. The speed is too high. Reduce the speed.
Compare the speed of the motor with the
specified pump speed. See the rating
plate.
When you adjust the speed (frequency
transformer), check the reference value
setting.
The impeller diameter is too large. Use a smaller impeller.
108 Model 3393 Installation, Operation, and Maintenance Manual