11. Troubleshooting
OFF
WARNING: Turn off the power supply before performing any operations.
Do not allow the pump or motor to run when dry even for a short period.
Strictly follow the user instructions and if necessary contact an authorised service centre
PROBLEM
PROBABLE CAUSES
1) The engine
1a) Unsuitable power supply
does not start
1b) Incorrect electrical connections
1c) Engine overload protective device cuts
in.
1d) Blown or defective fuses
1e) Shaft blocked
1f) Motor failed
2) Pump blocked
2a) Prolonged periods of inactivity .
2b) Presence of solid bodies in the impeller
2c) Bearings blocked
3)The pump
3a) Presence of air inside the pump or
functions but no
suction pipe
water comes out
3b) Possible infiltration of air.
3c) Foot valve blocked or suction pipe not
fully immersed in liquid
3d) Suction filter blocked
2e) Flap valve damaged, worn or faulty
(models NRD, NRD4)
4) Insufficient flow
4a) Pipes and accessories with diameter
too small
4b) Presence of deposits or solid bodies in
the impeller
4c) Rotor deteriorated
4d) Worn rotor and pump case
4e) Gases dissolved in the water
4f) Excessive viscosity of the liquid pumped
4g) Incorrect direction of rotation
4h) Flap valve damaged, worn or faulty
(models NRD, NRD4)
5) Noise and vibrations
5a) Worn bearings
from the pump
5b) Unbalanced power supply
6) Leakage from
6a) The mechanical seal has functioned
the mechanical
when dry or has stuck
seal
6b) Mechanical seal scored by presence of
abrasive parts in the liquid pumped
6c) Mechanical seal unsuitable for the type
of application
6d) Slight initial drip during filling or on first
start-up
NR(D), NR(D)4 Rev. 14 - Operating Instructions
POSSIBLE REMEDIES
1a) Check that the mains frequency and voltage are suitable.
1b) Connect the power supply cable correctly. Check the
setting of the thermal overload protection.
1c) Check the power supply and make sure that the pump
shaft is turning freely. Check the setting of the thermal
overload protection.
1d) Replace the fuses, check points a) and c)
1e) See "Blocked pump" instruction booklet
1f) Repair or replace the engine.
2a) Unblock the pump by using a screw driver to turn the
relevant notch on the back of the shaft.
2b) Remove any solid foreign bodies inside the impeller
2c) Replace the bearings.
3a) Release the air from the pump using the delivery control
valve.
3b) Check which part is not tight and seal the connection.
3c) Clean or replace the bottom valve and use a suitable
suction pipe .
3d) Clean the filter, if necessary, replace it . See point 2b)
also.
3e) Replace the flap valve
4a) Use pipes and accessories suitable for the specific
application
4b) Clean the impeller and install a suction filter
4c) Replace the impeller
4d) Replace the impeller and the pump casing
4e) Perform the opening and closing manoeuvres through the
feeder gate
4f) The pump is unsuitable
4g) Invert the electrical connections in the terminal board
4h) Replace the flap valve
5a) Replace the bearings
5b) Check that the mains voltage is right
In cases 6a), 6b) and 6c), replace the seal
6a) Make sure that the pump casing is full of liquid and that all
the air has been expelled.
6b) Install a suction filter and use a seal suited to the
characteristics of the liquid being pumped.
6c) Choose a seal with characteristics suitable for the specific
application
6d) Wait for the seal to adjust to the rotation of the shaft. If the
problem persists, see points 6a), 6b) or 6c).
EN
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