6. Troubleshooting
If you find any abnormal conditions of the pump, carefully investigate the problem. For overhaul,
replacement of the parts or repairs, ask the vendor or contact Teral or our servicing companies.
Problem
Cause (Reference page)
Action (Reference page)
The pump does
not start.
The motor does
not rotate.
Wiring is disconnected or broken.
Check the wires and connections to repair or
replace.
Poor connection or contact of power wires
(3-7)
Check by a tester and replace the defects with a
good one if any.
The power fuse is blown.
Replace it with an appropriate fuse.
Tripping of the thermal relay
Check the cause of tripping.
The power voltage is too low. (2-3)
Check the power voltage. In case of abnormal
condition, contact electric power company for
remedy.
The motor has failed.
Contact Teral or our servicing companies
because disassembly and inspection are
required.
Foreign matter is caught in the impeller.
The shaft seal is bound.
The bearing is rusty.
The pump starts,
but water does
not flow, or the
pump cannot
achieve the
specified
discharge rate
and the specified
head.
The priming in the casing is not enough. (4-2)
Fully prime the water.
The pumping liquid contains many bubbles.
Prevent the formation and suction of bubbles.
The air intrudes from the suction piping.
Check and repair the joint of each suction piping.
The rotation direction is reverse. (4-1)
Correct the wiring so that the motor rotates in
normal direction. (4-3)
The piping loss is high.
Check the diameter, route and length of the
pipes to reconsider the specifications.
The piping is clogged with foreign matter.
Check and clean the piping.
The impeller and the liner ring are worn.
Contact Teral or our servicing companies
because disassembly and inspection are
required.
Foreign matter is accumulated in the impeller
and in the casing.
The rotation speed is low.
-Check the number of poles of the motor. If it is
wrong, replace it with a correct one.
-Check the power voltage. In case of abnormal
condition, contact electric power company for
remedy.
The sluice valve is closed. (4-3)
Open the sluice valve.
There is a leak in the discharge pipe.
Check and repair the pipe.
The total suction head or discharge head is too
high. (2-3)
Reconsider the specification.
Cavitation occurred.(3-6)
Contact Teral or our servicing companies.
Overload and
overcurrent of the
motor
The rotation speed is too high.
-Check the number of poles of the motor. If it is
wrong, replace it with a correct one.
-Check the power voltage. In case of abnormal
condition, contact electric power company for
remedy.
The stator winding is broken, shorted, or
grounded.
Contact Teral or our servicing companies
because disassembly and inspection are
required.
The stator and rotor are in contact due to wear
of the bearing.
The motor is running in open-phase condition.
Check the wiring and repair or replace.
The setting of overload protection device is too
low.
Correctly set the motor overload protection
device.
The power supply voltage is out of the
allowable fluctuation range.(2-2)
Check the power voltage. In case of abnormal
condition, contact electric power company for
remedy.
A 50Hz pump is run in the 60Hz power zone.
Check the nameplate and replace with a correct
one.