Fault Finding The Product; The Pump Delivers No Liquid; The Pump Does Not Deliver Enough Liquid - Grundfos LSV Installation And Operating Instructions 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
The pump is not primed, lack of priming liquid,
incomplete priming.
Loss of priming liquid.
The suction lift or static lift is too high.
The outlet pressure is too high.
The speed is too low.
Wrong direction of rotation.
The impeller is completely clogged.

8.2 The pump does not deliver enough liquid

Cause
The suction lift or static lift is too high.
The outlet pressure is too high.
The speed is too low.
Remedy
• Fill the pump and inlet pipe completely with pumped
liquid.
• Mend possible leaks in the inlet pipe, joints and
fittings. Vent the pump housing to remove
accumulated air.
• Reduce the difference in height between the water
reservoir or water supply and the pump.
• 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.
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.
• 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.
• Dismantle the pump and clean the impeller.
Remedy
• Reduce the difference in height between the water
reservoir or water supply and the pump.
• 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.
1. Make sure that the motor receives full voltage.
2. Make sure that the frequency is correct.
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