Troubleshooting
Model 3410 Installation, Operation, and Maintenance Manual
72
Symptom
Cause
Remedy
The pump is noisy or vi-
brates.
The pump and driver are not aligned
properly.
Realign the pump and driver.
The impeller is partly clogged.
Back-flush the pump to clean the impeller.
The impeller or shaft is broken or bent.
Replace the impeller or shaft as necessary.
The foundation is not rigid.
Tighten the hold-down bolts of the pump and motor or
adjust the stilts.
The bearings are worn.
Replace the bearings.
Rotating parts are binding.
Check the internal wearing parts for proper clearances.
The pump is cavitating.
Locate and correct the system problem.
The pump leaks exces-
sively at the stuffing box.
The shaft is bent.
Straighten the shaft or replace it if necessary.
The pump and driver are not aligned
properly.
Realign the pump and driver.
The bearings are worn out or improperly
lubricated.
Inspect the bearings and replace them if necessary.
The stuffing box is over-
heating.
The stuffing box has air leaks.
Check the packing or seal and replace if necessary.
Check for the proper amount of lubrication.
The stuffing box is improperly packed.
Check the packing and repack the stuffing box. If the
packing is too tight, then try releasing the gland pressure
and tightening again.
The incorrect packing or mechanical seal
has been installed.
Consult with ITT.
The mechanical seal is damaged.
Inspect and replace the mechanical seal as necessary.
Consult with ITT.
The shaft sleeve is scored.
Machine or replace the shaft sleeve as necessary.
The packing is too tight or the mechanical
seal is not adjusted properly.
Check and adjust the packing. Replace any parts as
necessary. Adjust the mechanical seals. Consult the
instructions supplied by the seal manufacturer or consult
with ITT.
The motor requires ex-
cessive power.
The discharge head has dropped below
the rated point and is pumping too much
liquid.
Install a throttle valve. If this does not help, then trim the
impeller diameter.
If this does not help, then consult an ITT representative.
The liquid is heavier than expected.
Check the specific gravity and viscosity.
The shaft is rotating in the wrong direction. Change the rotation. The rotation must match the arrow
on the bearing housing or pump casing.
The impeller is damaged.
Inspect the impeller and replace it if necessary.
Rotating parts are binding.
Check the internal wearing parts for proper clearances.
The shaft is bent.
Straighten the shaft or replace it if necessary.
The motor speed is too high.
Check the motor voltage or the steam pressure received
by turbines. Make sure the motor speed matches the
speed on the nameplate.
The stuffing box is improperly packed.
Check the packing and repack the stuffing box. If the
packing is too tight, then try releasing the gland pressure
and tightening again.
The bearings are worn out or improperly
lubricated.
Inspect the bearings and replace them if necessary.
The running clearances between the wear
rings are incorrect.
Check for the proper clearances. Replace the casing or
impeller wear rings if necessary.
There is excessive pipe strain on the pump
casing.
Relieve the strain and check the alignment. Consult ITT if
necessary.
The amount of available NPSH is not
sufficient.
1.
Increase the positive suction head by lowering the
pump or increasing the suction pipe and fittings size.
2.
Sub-cool the suction piping at the inlet to lower the
temperature of liquid that is entering the pump.
3.
Pressurize the suction vessel.
The pump and driver are not aligned.
Realign the pump and driver.
The suction inlet is not submersed deep
enough.
If the inlet cannot be lowered or if the problem persists
after the inlet is lowered, then chain a board to the
suction pipe. The board will be drawn into the eddies and
smother the vortex.
The casing is distorted due to excessive
strains from the suction and discharge
piping.
Check the alignment. Examine the pump for rubbing
between the impeller and the casing. Replace damaged
parts and redo the piping.