5.4 The pump starts-stops-starts in rapid sequence
Cause
Remedy
The pump starts due to back-flow
which fills the sump to the start level
again.
Check that:
• The distance between the start and stop levels is sufficient.
• The non-return valve(s) work(s) properly.
• The length of the discharge pipe between the pump and the first non-
return valve is sufficiently short.
The self-holding function of the
contactor malfunctions.
Check:
• The contactor connections.
• The voltage in the control circuit in relation to the rated voltages on the
coil.
• The functioning of the stop-level regulator.
• Whether the voltage drop in the line at the starting surge causes the
contactor's self-holding malfunction.
If the problem persists, then contact a sales or authorized service representative.
Always state the serial number of the product, see
5.5 The pump runs but the motor protection trips
DANGER: Crush Hazard
Moving parts can entangle or crush. Always disconnect and lock out power before
servicing to prevent unexpected startup. Failure to do so could result in death or serious
injury.
NOTICE:
Do NOT override the motor protection repeatedly if it has tripped. Doing so may result in
equipment damage.
Cause
Remedy
The motor protection is set too low.
Set the motor protection according to the data plate and if applicable the
cable chart.
The impeller is difficult to rotate by
hand.
• Clean the impeller.
• Clean out the sump.
• Check that the impeller is properly trimmed.
The drive unit is not receiving full
voltage on all three phases.
• Check the fuses. Replace fuses that have tripped.
• If the fuses are intact, then notify a certified electrician.
The phase currents vary, or they are
too high.
Contact a sales or authorized service representative.
The insulation between the phases
and ground in the stator is defective.
1. Use an insulation tester. With a 1000 V DC megger, check that the
insulation between the phases and between any phase and ground is >
5 megaohms.
2. If the insulation is less, then do the following:
Contact a sales or authorized service representative.
5 Troubleshooting
2620.172/.281 Service and Repair Instructions
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Summary of Contents for Flygt 2620.172
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