Grundfos NBS, Инструкция по эксплуатации

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Fault Cause Remedy
3. The pump makes too much
noise. The pump runs un-
evenly and vibrates.
a) The inlet pressure is too low,resulting in
cavitation in the pump.
• Increase the liquid level on the inlet side.
• Open the isolating valve in the inlet pipe.
• Make sure that all the conditions in section Pipes are com-
plied with.
b) There is air in the inlet pipe or pump. • Vent the inlet pipe or the pump.
c) The counterpressure is lower than speci-
fied. • Set the duty point according to the flow and head that the
pump is selected for.
d) The pump draws in air due to low liquid lev-
el. • Increase the liquid level on the inlet side and keep it as
constant as possible.
e) The impeller is out of balance or the impel-
ler blades are clogged.
1. Clean the impeller.
2. Check the impeller blades, clean them if necessary.
f) The split coupling is out of balance.
1. Check coupling gap and that set screws in split coupling
are tightened.
2. Disassemble split coupling to inspect keys and keyways
and their alignment with coupling pieces.
g) The inner parts are worn. • Replace the defective parts.
h) The pump is stressed by the pipes thus
causing starting noise.
• Mount the pump so that it is not stressed.
• Support the pipes.
i) The bearings are defective. • Replace the bearings.
j) The motor fan is defective. • Replace the fan.
k) There are foreign bodies in the pump. • Clean the pump.
l) Frequency converter operation causes
noise. • Find the different remedies in Frequency converter opera-
tion section. See section Frequency converter operation.
4. The pump, connections or
mechanical shaft seal is leak-
ing.
a) The pump is stressed by the pipes which
causes leaks in the pump housing or at con-
nections.
• Mount the pump so that it is not stressed.
• Support the pipes.
b) Pump housing gaskets and gaskets at con-
nections are defective. • Replace the pump housing gaskets or gaskets at connec-
tions.
c) The mechanical shaft seal is dirty or stuck
together.
• Check and clean the mechanical shaft seal.
d) The mechanical shaft seal is defective. • Replace the mechanical shaft seal.
e) The shaft surface is defective. • Replace the shaft.
5. The temperature in the
pump or motor is too high.
a)There is air in the inlet pipe or pump.
1. Vent the inlet pipe or the pump.
2. Fill up the inlet pope and the pump again.
b) The inlet pressure is too low.
• Increase the liquid level on the inlet side.
• Open the isolating valve in the inlet pipe.
• Make sure that all the conditions in section Pipes are com-
plied with.
c) The bearings are lubricated with too little,
too much or unsuitable lubricant.
• Replenish, reduce or replace the lubricant.
d) The axial pressure is too high.
1. Check the relief holes of the impeller on the inlet side.
2. Clean the holes, if necessary
e) The motor-protective circuit breaker is de-
fective or the setting is incorrect.
1. Check the setting of the motor-protective circuit breaker.
2. Replace the circuit breaker if necessary.
f) The motor is overloaded. • Reduce the flow rate.
30
English (GB)