Grundfos SP Series Installation And Operating Instructions Manual page 17

Problem Possible cause/how to check
4. Pump cycles too a) Pressure switch is not properly
much.
b) Level control is not properly set or
c) Insufficient air charging or leaking
d) Plugged snifter valve or bleed
e) Tank is too small.
5. Fuses blow or a) High or low voltage.
circuit breakers
trip
b) Three-phase current unbalance.
c) Control box wiring and
adjusted or is defective.
How to check:
Check pressure setting on switch
and operation. Check voltage
across closed contacts.
is defective.
How to check:
Check setting and operation.
tank or piping.
How to check:
Pump air into tank or diaphram
chamber. Check diaphram for leak.
Check tank and piping for leaks
with soap and water solution.
Check air to water volume.
orifice.
How to check:
Examine valve and orifice for dirt
or corrosion.
How to check:
Check tank size. Tank volume
should be approximately 10
gallons for each gpm or pump
capacity.
How to check:
Check voltage at pump panel. If
not within ± 10%, check wire size
and length of run to pump panel.
How to check:
Check current draw on each lead.
Unbalance must be within ± 5%.
components (single-phase only).
How to check:
Check that control box parts match
the parts list. Check to see that
wiring matches wiring diagram.
Check for loose or broken wires or
terminals.
Possible remedy
Re-adjust switch or replace if
defective.
Re-adjust setting (refer to
manufacturer data.) Replace if
defective.
Repair or replace damaged
component.
Clean and/or replace snifter valve or
bleed orifice if defective.
If tank is too small, replace with proper
size tank.
If wire size is correct, contact power
company. If not, correct and/or replace
as necessary.
If current unbalance is not within
± 5%, contact power company.
Correct as required.
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