Stübbe SHM 20-15, Original Operating Manual

Page: 27 / 35

Troubleshooting
Fault number
1 2 3 4 5 6 7 8
Cause Remedy
–
X
–
X
–
X
– –
Suction head too large: NPSH
pump
is larger
than NPSH
system
Increase pump inlet pressure.
Consult the manufacturer.
— X — X — X — — Back pressure of the system is too high,
pump selected is too small.
Consult the manufacturer.
X
– – – –
X
– –
Intake/suction pipe and pump not correctly
vented or not completely filled Completely fill and vent pump and/or
pipe.
X
– – – –
X
– –
Intake / suction pipe contains trapped air Install fitting for venting.
Adjust piping installation.
X X
–
X
–
X
– –
Air is sucked in
Seal source of problem.
X X
–
X
–
X
– –
Proportion of gas too high: pump is
cavitating Consult the manufacturer.
–
X
–
X
–
X
– –
Temperature of fluid is too high: pump is
cavitating Increase pump inlet pressure.
Lower temperature.
Contact the manufacturer.
–
X
–
X
– – –
X Viscosity or specific gravity of the pumped
liquid outside the range specified for the
pump Consult the manufacturer.
–
X
–
X
– – – –
Geodetic differential head and/or pipe flow
resistances too high Remove sediments from the pump
and/or pressure pipe.
Install a larger impeller and consult the
manufacturer.
–
X
– –
X X
– –
Pressure-side fitting not opened wide
enough Open the pressure-side fitting.
X X
–
X
– – – –
Magnetic coupling has parted
Switch off pump and switch on again.
X X
– –
X X
– –
Pressure pipe blocked Clean the pressure pipe.
X X
–
X
–
X
– –
Pump running in the wrong direction Change over any two phases in the
motor.
X X
–
X
– – – –
Motor speed too low Compare the required motor speed with
the specifications on the pump type
plate. Replace the motor if necessary.
Increase the motor speed if speed
control is available.
–
X
–
X
–
X
– –
Pump parts worn Replace the worn pump parts.
– –
X X
–
X
–
X Pressure-side fitting opened too wide Throttle down at the pressure-side fitting.
Machine the impeller down. Consult the
manufacturer and adjust the impeller
diameter.
– –
X
– –
X
–
X Geodetic differential head, pipe flow
resistances and/or other resistances lower
than specified Throttle down the flow rate at the
pressure-side fitting. Observe the
minimum flow rate.
Machine the impeller down. Consult the
manufacturer and adjust the impeller
diameter.
– –
X
–
X
– – –
Viscosity lower than expected Machine the impeller down. Consult the
manufacturer and adjust the impeller
diameter.
300 092 BA-2018.08.21 EN SHM 27