Grundfos MTS Serie Montage- Und Betriebsanleitung Seite 23

Fault number
1 2 3 4 5 6
X X - X X -
X X - X X -
X X - X X -
X X - X X -
X X - X - -
- X - X X -
- X - X - -
- - X - X -
- X - X - -
- X - X X -
- X - X X -
- X - X X -
- X - X X -
- X - X - -
- X - X X X
Cause
7 8
Supply or suction pipe, rotor housing
- - or suction casing blocked or
encrusted.
- - Air is sucked in.
Pump is cavitating due to excessive
- -
amount of gas.
Excess play between:
- - • spindles
• spindles and housing.
X - Shaft seal is leaking excessively.
- X Motor is running on two phases.
- - Motor speed is too low.
- X Motor speed is too high.
Isolating valve in supply or suction
- -
pipe is not fully opened.
Supply or suction pipe cross-section
- -
is too small.
Suction height too high: NPSH
- -
is larger than NPSH
Pump is cavitating because pumped
- -
liquid temperature is too high.
Hydraulic parts of the pump are dirty,
- -
clotted or encrusted.
Viscosity or specific gravity of the
- X pumped liquid is outside the range
specified for the pump.
- - Pump parts are worn.
Remedy
• Clean the supply or suction pipe,
rotor housing or suction casing.
• Clean the suction casing.
• Seal the source of air leakage or
repair the malfunctioning
component, if necessary.
• Check the pipes.
• Clean or enlarge the filter.
• Install supply or suction pipe with
a bigger cross-section.
• Repair or replace any worn parts.
• Replace the shaft seal.
• Check the fuse and replace it, if
necessary.
• Check the cable connections and
insulation. Replace the cable, if
necessary.
• Compare the required motor
speed with the specifications on
the pump nameplate. Replace the
motor, if necessary.
• Increase the motor speed if speed
control is available.
• Compare the required motor
speed with the specifications on
the pump nameplate. Replace the
motor, if necessary.
• Reduce the motor speed if speed
control is available.
• Open the valve completely.
• Install supply or suction pipe with
a larger cross-section.
• Remove any encrustations from
the suction pipe.
• Open the valve completely.
• Increase the supply or inlet
pump
pressure.
.
system
• Consult the manufacturer.
• Increase the supply or inlet
pressure.
• Lower the pumped liquid
temperature.
• Consult the manufacturer.
• Dismount the pump and clean the
parts.
• Consult the manufacturer.
• Replace the worn pump parts.
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