13 (16) • No: 90 072 01 Rev 1 2005.07
Safety
When working on the motor, make sure
that the power is switched off.
When starting the pump, ensure nobody
goes near rotating parts.
Trouble shooting list
Problem
Pump does not start
Pump starts and
stops repeatedly
Current too high
Pump runs but
no flow or too
low flow
Possible cause
No voltage on motor
terminals
Motor failure
Fault in power supply
Motor overloaded
Motor overheated
Fault in power supply
Pump failure
Clogging or air lock
Pump failure
Fault in power supply
Too low capacity
Required action
Check power supply
Check motor protection
Check motor wiring
Check power supply
Check pump
Check cooling
Check motor
Check power supply
Check pump
Check dicharge and
coupling
Check pump
Check power supply
Check discharge
Checkpoints
• No power
• Main isolator switch
• Fuses
• Earth leakage relay
• Motor protection relay
• Motor temperature
• Continuity and isolation
• Phase resistance
• Low voltage
• Not all 3 phases available
• Setting of motor protection
• Wrong direction of rotation
• Impeller blocked
• Protection in automatic reset mode
• Continuity and isolation
• Fuses
• Low voltage
• Impeller blocked
• Visc. or spec. gravity too high
• Wrong direction of rotation
• Discharge obstructed
• Valve fully or partly closed
• Air pocket in pump or discharge
• Coupling leaks
• Impeller or volute blocked
• Pump is sucking to much air
• Worn or broken impeller
• Controlpanel
• Fuses
• Low voltage
• Discharge obstructed
• Valve fully or partly closed
• Air pocket
Trouble shooting
Attention!
• When working on the pump, make sure it cannot
start unexpectedly!
• Only qualified electricians may do the
electrical work.
Observe local electrical and safety regulations!