Publicité
K K
20. CAUSES OF FAULTY OPERATION
Faults
1. The electric pump fails to
start.
GB
2. The electric pump starts
but the overload relay
trips.
3. The electric pump fails to
deliver the right head.
22
Probable causes
1.1. Motor is not powered.
1.2. The selector switch is in the OFF position.
1.3. The thermal relay has tripped.
1.4. The fuses have burnt out owing to an excessive
overload.
1.5. A phase is missing.
2.1. Full voltage is not reaching all the motor
phases.
2.2. The thermal relay setting is too low.
2.3. Poor/no motor insulation.
2.4. Unbalanced power input in the phases.
2.5. The impeller may be clogged, blocked or
damaged.
2.6. Viscosity and/density of the raised liquid too
high.
3.1. The gate valve on the intake or delivery parts is
partially closed or clogged.
3.2. The check valve is partially clogged.
3.3. The suction/delivery pipe is clogged.
3.4. The electric pump turns in the wrong direction
3.5. The head provided by the electric pump has
dropped.
3.6. There are leaks from the system inside the
pumping station.
3.7. Worn hydraulic part.
Remedies
1.1. Check whether the fuses have burnt out
or whether a circuit protecting relay has
activated.
1.2. Select the ON position.
1.3. Identify and eliminate the cause. Check the
setting. Reset the thermal relay.
1.4. Identify the cause and replace the fuses.
1.5. Eliminate the cause and check the mains
connections.
2.1. Make sure that the fuses of the electrical
equipment are undamaged.
2.2. Check and correct the setting if necessary.
2.3. Disconnect the motor from the power source
and check its insulation.
2.4. Check the power input of the phases.
Unbalances should not exceed 5%. If there
is an unbalance, contact a specialized
workshop.
2.5. If the results of the electrical inspections
listed above are negative, remove the
electric pump from the tank and check
whether the impeller is blocked.
2.6. Make sure that the right pump/motor
combination has been selected.
3.1. Open or unblock the gate valves.
3.2. Release the valve. If there is an external
lever, move it backwards and forwards
several times.
3.3. Pump clean washing water or pump water at
high pressure through the pipes with a hose.
3.4. Electric pumps that turn at low speed
may spin in the opposite direction without
producing much noise or vibrations
(particular the KCV versions). Make sure that
the motor turns in the right direction.
3.5. Check the total head with a pressure
gauge whilst the electric pump is operating.
Compare the measured value with the one
given in the documentation or (even better)
with previous readings. If the electric pump
has been operating for some time and the
head has dropped, remove the electric pump
and check it for wear. Make sure that the
impeller is not obstructed in any way.
3.6. Check and repair any damage sustained.
3.7. Compensate for the wear by adjusting the
suction support of the pump casing (KT
only), or replace the worn parts.
Caprari S.p.A.
Publicité
