Fault Finding The Product - Grundfos MTH Serie Instrucciones De Instalación Y Funcionamiento

6. Fault finding the product

WARNING
Electric shock
Death or serious personal injury
- Before starting any work on the product,
make sure that the power supply has
been switched off and that it cannot be
accidentally switched on.
- Connect the pump to an external main
switch close to the pump and to a
motor-protective circuit breaker or a
CUE frequency converter.
- Make sure you can lock the main switch
in OFF position (isolated). Type and
requirements as specified in EN 60204-
1, 5.3.2.
Fault
1. The motor does
not run when
started.
2. The motor-
protective circuit
breaker overload
trips immediately
when the supply
is switched on.
3. The motor-
protective circuit
breaker overload
trips occasionally.
4. The motor-
protective circuit
breaker has not
tripped but the
pump does not
run.
12
Cause
a) Supply failure.
b) The fuses are blown.
c) The motor-protective circuit breaker
overload has tripped.
d) The main contacts in the motor-
protective circuit breaker are not
making contact or the coil is faulty.
e) The control circuit is defective.
f) The motor is defective.
a) One fuse is blown or the motor-
protective circuit breaker has tripped.
b) The contacts in the motor-protective
circuit breaker overload are faulty.
c) The cable connection is loose or
faulty.
d) The motor winding is defective.
e) The pump is mechanically blocked.
f) The overload setting of the motor-
protective circuit breaker is too low.
a) The overload setting of the motor-
protective circuit breaker is too low.
b) The voltage is low at peak times.
a) Check 1 a), b), d) and e).
CAUTION
Toxic liquids
Death or serious personal injury
- Wear personal protective equipment.
CAUTION
Hot or cold liquid
Minor or moderate personal injury
- Wear personal protective equipment.
CAUTION
Hot or cold surface
Minor or moderate personal injury
- Make sure that no one can accidentally
come into contact with hot or cold
surfaces.
Remedy
Connect the electricity supply.
Replace fuses.
Reactivate the motor-protective circuit
breaker.
Replace contacts or magnetic coil.
Repair the control circuit.
Replace the pump.
Replace the fuse or reactivate the
motor-protective circuit breaker.
Replace the motor-protective circuit
breaker contacts.
Fasten or replace the cable
connection.
Replace the pump.
Remove the mechanical blocking of
the pump.
Set the motor-protective circuit breaker
correctly.
Set the motor-protective circuit breaker
correctly.
Check the electricity supply.