EN
Operating and
maintenance manual
Horizontal multi-stage pump
Serie MH
8 DISPOSAL
Disposal of this product or parts of it must be carried out using the local public or
private waste disposal systems.
9 TROUBLESHOOTING
WARNING: Before any repairs to the electric pump, check that the power
supply is disconnected and that it cannot be accidentally reconnected
during maintenance operations.
WARNING: If the electric pump is used for hot and/or hazardous liquids, it is
essential to inform the personnel who will carry out the repair. In this case,
clean the pump so as to ensure the safety of the operator.
For
problems
and
solutions,
consult
table
below:
“TROUBLESHOOTING TABLE”
N
O
I
T
C
A
E
S
U
A
C
M
E
L
B
O
R
P
9.1
The pump turns but does
not deliver
a)
The internal parts are obstructed by foreign bodies:
Dismantle the pump and clean it.
b)
Inlet pipe is blocked:
Clean the pipe.
c)
Air is entering the inlet pipe:
Check that the pipe is airtight right up to the pump and seal it.
d)
The pump is unprimed:
Re-prime it by filling the pump. Check that the base valve is
airtight.
e)
Inlet pressure is too low and generally accompanied by
cavitation noise:
Excessive loss of head in suction or the suction height is
excessive (check the NPSH of the installed pump).
f)
Voltage insufficient to power the motor:
Check the voltage of the motor terminals and the correct
diameter of the conductors.
9.2
The pump vibrates
a)
Anchorage on a faulty base:
Check and fully tighten the nuts on the bolts of the studs.
b)
Foreign bodies obstructing the pump:
Dismantle the pump and clean it.
c)
Obstruction to the pump rotation:
Check that the pump can rotate freely without any abnormal
resistance.
d)
Faulty electrical connection:
Check the pump connections.
9.3
The motor heats up
abnormally
a)
Insufficient voltage:
Check the voltage of the motor terminals. The voltage should
be ± 10% of the rated voltage.
b)
Pump blocked by foreign bodies:
Dismantle the pump and clean it.
c)
Ambient temperature more than +40°C:
The motor is designed to function at a maximum ambient
temperature of +40°C.
d)
Connection error in the terminal board:
Check that the connections respect the diagram shown inside
the cover of the terminal box and the data plate information.
9.4
The pump does not deliver
sufficient pressure
a)
The motor is not rotating at normal speed (foreign bodies
or faulty power supply etc.)
Dismantle the pump and correct the problem.
b)
The motor is faulty:
Replace it.
c)
The pump is not filling properly:
Repeat the priming operation.
d)
The motor rotates in reverse (three-phase motor):
Invert the direction of rotation by exchanging two phase wires
on the motor terminal board or the electrical control panel.
e)
Voltage insufficient to power the motor:
Check the voltage of the motor terminals and the correct
diameter of the conductors.
9.5
The automatic circuit
breaker trips
a)
Thermal overload relay value too low:
Control the intensity with an ammeter, set the value of the
intensity shown on the motor rating plate.
b)
Voltage is too low:
Check that the diameter of the conductors of the electric cable
is correct.
c)
Interruption of one phase:
Check the electric cable or fuse and replace if necessary.
d)
The thermal overload relay relay is faulty:
Replace it.
9.6
The flow is not regular
a)
The inlet height is not being observed:
Check the installation conditions and the recommendations of
this manual.
b)
The inlet piping has a smaller diameter than the pump:
The inlet piping should have the same diameter as the inlet
mouth.
c)
The suction filter and inlet piping are partially blocked:
Clean the inlet duct.
TROUBLESHOOTING TABLE:
