Grundfos SP Serie Instrucciones De Instalación Y Operación página 31

Problem Possible cause and/or how to check
5. Fuses blow or a)
circuit
breakers trip.
b)
c)
d)
e)
The voltage is too high or low.
How to check:
Check the voltage at the pump
control panel. If not within ± 10 %,
check the cable size and length of
run to pump control panel.
The three-phase current imbalance
is too high or low.
How to check:
Check the current draw on each
lead. The imbalance must be within ±
5 %.
The control box wiring and
components are incorrect or
defective (single-phase only).
How to check:
Check that the control box parts
match the parts list. Check to see
that the wiring matches the wiring
diagram. Check for loose or broken
wires or terminals.
The capacitor is defective (single-
phase only).
How to check:
Turn off the power, then the
capacitor. Check by means of an
ohmmeter (Rx100K). When the
ohmmeter is connected, look for the
needle to jump forward and slowly
drift back.
The starting relay is defective
(certain types of single-phase only).
How to check:
Check the resistance of the relay coil
by means of an ohmmeter
(Rx1000K). Check the contacts for
wear.
Possible remedy
If the cable size is correct, contact
the power company. If not, correct
and/or replace as necessary.
If current imbalance is not within ±
5 %, contact the power supply
company.
Correct as required.
If there is no ohmmeter needle
movement, replace the capacitor.
Replace any defective starting
relay.
31