7 Troubleshooting
7.1 Troubleshooting
Symptom
Cause
Remedy
The pump is not deliv-
ering liquid.
The pump is not primed.
Re-prime the pump and check that the pump and
suction line are full of liquid.
The pump has lost prime.
Check for leaks in the suction pipe joints and fit-
tings. Vent the casing to remove accumulated air.
Check the mechanical seal or packing.
The impeller is clogged.
Back-flush the pump in order to clean the impeller.
The impeller is loose on the shaft.
Check the key, locknut, and setscrews.
The shaft is rotating in the wrong direc-
tion.
Change the rotation. The rotation must match the
arrow on the bearing housing or pump casing.
The shaft is not rotating at all.
Check the power, coupling, line shaft, and shaft
keys.
The foot valve or suction pipe opening
is not submerged enough.
Consult an ITT representative for the proper sub-
mersion depth. Use a baffle to eliminate vortices.
The suction lift is too high.
Check for obstructions at the inlet and make sure
the suction valves are open. Check for pipe friction
losses. Use a vacuum or compound gauge to
check the NPSH available.
The motor speed is too low.
Make sure that the motor wiring is correct and re-
ceives full voltage or that the turbine receives full
steam pressure. The motor can have an open
phase.
The system static head is too high.
Check with ITT to determine whether a larger im-
peller can be used. If not, then cut pipe losses, in-
crease the speed, or both. Do not overload the
driver.
The system head or discharge head is
too high.
Check for pipe friction losses and that the valves
are wide open. The condition can be corrected with
larger piping.
The pump is not deliv-
ering enough liquid or
pressure.
The suction piping has air leaks.
Check the suction piping for air pockets and air
leaks.
The stuffing box has air leaks.
Check the packing or seal and replace if necessa-
ry. Check for the proper amount of lubrication.
The motor speed is too low.
Make sure that the motor wiring is correct and re-
ceives full voltage or that the turbine receives full
steam pressure. The motor can have an open
phase.
The discharge head is too high.
Check for pipe friction losses and that the valves
are wide open. The condition can be corrected with
larger piping.
The suction lift is too high.
Check for obstructions at the inlet and make sure
the suction valves are open. Check for pipe friction
losses. Use a vacuum or compound gauge to
check the NPSH available.
The impeller is clogged.
Back-flush the pump in order to clean the impeller.
The amount of available NPSH is not
sufficient.
1.
Increase the positive suction head by low-
ering the pump or increasing the suction
pipe and fittings size.
7 Troubleshooting
74
Model 3410 Installation, Operation, and Maintenance Manual
Содержание GOULDS PUMPS 3410
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