Goulds Pumps 3393 - IOM - Manual (Page 111)

Troubleshooting
Symptom Cause Remedy
The drive mechanism is overloaded The back pressure and discharge pres- Throttle the discharge valve.
sure are too low.
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.
The density and/or viscosity of the Seek assistance.
pumped liquid is too high.
The shaft seal is worn.
Replace the mechanical seal.
Check the sealing, flushing, and cooling
pipe (pressure).
Avoid running the pump dry.
There is not enough sealing. Tighten the screws.
Replace the mechanical seal.
The discharge pressure is too low. Increase the minimum amount being car-
ried. Open the control valves and bypass
piping.
There is not enough hydraulic thrust bal- Clean the relief holes in the impeller.
ance. Replace the worn impeller and wear rings.
The pump is not running quietly. The pump and/or pipes are not complete- Fill with liquid
ly filled with liquid.
Vent the pump and/or pipes.
The NPSH 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.
The inner components are suffering from Replace the worn parts.
wear.
Forces in the pipeline are too high and the Change the position of the support pipes
pump is under strain.
and use compensators.
Check that the foundation plate and frame
are properly cast and in place.
There is too much, not enough, or the Change the lubricant.
wrong type of lubricant.
The electrical supply is incorrect.
Check the voltage of all phases (2-phase
running).
Check the cable connections.
Check the fuses.
The sealing is insufficient. Tighten the screws.
Replace the mechanical seal.
There is not enough hydraulic thrust bal- Clean the relief holes in the impeller.
ance.
Replace the worn impeller and wear rings.
There is system-related vibration (reso- Seek assistance.
nance).
The pump casing becomes warm during The pump or suction/intake pipe is Clean the pump and pipes.
operation. blocked
The NPSH is too low.
Increase the liquid level.
Increase the suction pressure.
Reduce the resistance in the intake/suc-
tion pipe. Change the path and pipe size,
open the shutoff valves, and clean the
filters.
The inner components are suffering from Replace the worn parts.
wear.
There is system-related vibration (reso-
Seek assistance.
nance).
Model 3393 Installation, Operation, and Maintenance Manual 109