Grundfos LS User Manual

8. Fault finding the product
DANGER
Electric shock
Death or serious personal injury
‐ Before you remove the terminal box cover and before you remove or dismantle the pump, make
sure that the power supply has been switched off and that it cannot be accidentally switched on.
8.1 The pump delivers no liquid
Cause Remedy
The pump is not primed, lack of priming liquid,
incomplete priming.
• Fill the pump and inlet pipe completely with pumped
liquid.
Loss of priming liquid.
• Mend possible leaks in the inlet pipe, joints and
fittings. Vent the pump housing to remove
accumulated air.
The suction lift or static lift is too high.
• Reduce the difference in height between the water
reservoir or water supply and the pump.
The outlet pressure is too high.
• Make sure that valves in the outlet pipe are fully
open.
• For parallel operation, this indicates that the outlet
pressure is higher than designed friction losses in
the pipes. Review system design and actual
pressure developed in the system with parallel
operation.
The speed is too low. 1. Make sure that the motor receives full voltage.
2. Make sure that the frequency is correct.
3. Make sure that all phases are connected.
Wrong direction of rotation.
• Compare the direction of rotation with the directional
arrow on the pump housing. If required, change the
direction of rotation by interchanging two phases in
the motor.
The impeller is completely clogged.
• Dismantle the pump and clean the impeller.
8.2 The pump does not deliver enough liquid
Cause Remedy
The suction lift or static lift is too high.
• Reduce the difference in height between the water
reservoir or water supply and the pump.
The outlet pressure is too high.
• Make sure that valves in the outlet pipe are fully
open.
• For parallel operation, this indicates that the outlet
pressure is higher than designed friction losses in
the pipes. Review system design and actual
pressure developed in the system with parallel
operation.
The speed is too low. 1. Make sure that the motor receives full voltage.
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English (GB)

Grundfos LS Specifications

General

Type	Submersible Pump
Protection class	IP68
Frequency	50 Hz
Application	Drainage
Liquid Temperature	0 °C to 40 °C
Seal Type	Mechanical seal