Lowara NSC2 Manual De Instalación, Funcionamiento Y Mantenimiento página 21

1. Start the motor.
2. Gradually open the on-off valve on the dis-
charge side of the pump.
At the expected operating conditions, the pump
must run smoothly and quietly. If not, refer to
Troubleshooting (page 21).
6 Maintenance
Precautions
Electrical Hazard:
Disconnect and lock out electrical power
before installing or servicing the unit.
WARNING:
• Maintenance and service must be
performed by skilled and qualified
personnel only.
• Observe accident prevention regula-
tions in force.
• Use suitable equipment and protec-
tion.
• Make sure that the drained liquid
does not cause damage or injuries.
6.1 Service
If the user wishes to schedule regular maintenance
deadlines, they are dependent on the type of pump-
ed liquid and on the operating conditions of the
pump.
Contact the local sales and service representative
for any requests or information regarding routine
maintenance or service.
Extraordinary maintenance may be necessary to
clean the liquid end and/or replace worn parts.
Motor bearings
After approximately five years, the grease in the mo-
tor bearings is so aged that a replacement of the
bearings is recommended. The bearings must be re-
placed after 25000 operating hours or according to
the motor supplier maintenance instructions, which-
ever is shorter.
Motor with regreasable bearings
Follow motor supplier maintenance instructions.
6.2 Inspection checklist
Check for leakage of the mechanical seal. Replace
the mechanical seal if leakage is found.
6.3 Disassemble and replace the pump
parts
For more information about spare parts and assem-
bly and disassembly of the pump, contact the local
sales and service representative.
7 Troubleshooting
7.1 Troubleshooting for users
The main switch is on, but the electric pump
does not start.
Cause
The thermal protector
incorporated in the
pump (if any) has trip-
ped.
The protective device
against dry running has
tripped.
The electric pump starts, but the thermal protection
trips a varying time after.
Cause
There are foreign objects
(solids or fibrous sub-
stances) inside the pump
which have jammed the
impeller.
The pump is overloaded
because it is pumping liq-
uid that is too dense and
viscous.
The pump runs but delivers too little or no liquid.
Cause Remedy
The pump is clog- Contact the Sales and Service
ged. Department.
The troubleshooting instructions in the tables below
are for installers only.
7.2 The main switch is on, but the
electric pump does not start
Cause
There is no power
supply.
The thermal protector
incorporated in the
pump (if any) has trip-
ped.
The thermal relay or
motor protector in the
electric control panel
has tripped.
The protective device
against dry running
has tripped.
The fuses for the
pump or auxiliary cir-
cuits are blown.
en - Original instructions
Remedy
Wait until the pump has
cooled down. The thermal
protector will automatical-
ly reset.
Check the liquid level in
the tank, or the mains
pressure.
Remedy
Contact the Sales and
Service Department.
Check the actual power
requirements based on
the characteristics of the
pumped liquid and then
contact the Sales and
Service Department.
Remedy
• Restore the power sup-
ply.
• Make sure all electrical
connections to the pow-
er supply are intact.
Wait until the pump has
cooled down. The thermal
protector will automatically
reset.
Reset the thermal protec-
tion.
Check the:
• liquid level in the tank,
or the mains pressure
• protective device and its
connecting cables
Replace the fuses.
21