Grundfos CMV, Инструкция по установке и эксплуатации

Страница: 13 / 22

English (GB)
13
13. Fault finding
Warning
Before removing the terminal box cover, make sure that the power supply has been switched
off.
The pumped liquid may be scalding hot and under high pressure. Before any removal or
dismantling of the pump, the system must therefore be drained, or the isolating valves on
either side of the pump must be closed.
Fault Cause Remedy
1. The pump does not run. a) Supply failure. Switch on the switch. Check cables
and cable connections for defects
and loose connections.
b) Fuses are blown. Check cables and cable connections
for defects, and replace the fuses.
c) Motor protection tripped. See 2. a), b), c), d), e), f).
d) Control-current circuit
defective. Repair or replace the control-current
circuit.
2. Motor-protective circuit
breaker has tripped
(trips out immediately when
supply is switched on). a) Fuses are blown. See 1. b).
b) Contacts of the
motor-protective circuit
breaker or magnet coil
defective. Replace the contacts of the
motor-protective circuit breaker,
the magnet coil or the entire
motor-protective circuit breaker.
c) Cable connection is loose or
faulty. Check cables and cable connections
for defects, and replace the fuses.
d) Motor winding is defective. Repair or replace the motor.
e) The pump is mechanically
blocked. Switch off the power supply, and
clean or repair the pump.
f) The setting of the
motor-protective circuit
breaker is too low. Set the motor-protective circuit
breaker according to the rated
current of the motor (I
1/1
).
See nameplate.
3. The motor-protective circuit
breaker trips out
occasionally. a) The setting of the
motor-protective circuit
breaker is too low. See 2. f).
b) Periodic supply failure. See 2. c).
c) Periodically low voltage. Check cables and cable connections
for defects and loose connections.
Check that the supply cable of the
pump is correctly sized.
4. The motor-protective circuit
breaker has not tripped out,
but the pump is
inadvertently out of
operation. a) See 1. a), b), d) and 2. e).
5. The pump performance is
unstable. a) Pump inlet pressure too low. Check the inlet conditions of the
pump.
b) Suction pipe is partly blocked
by impurities. Remove and clean the suction pipe.
c) Leakage in suction pipe. Remove and repair the suction pipe.
d) Air in suction pipe or pump. Vent the suction pipe/pump.
Check the inlet conditions of the
pump.