Grundfos SP - Page 29

29
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2. The pump
runs but does
not deliver
water.
a) The groundwater level in the well is
too low or the well is collapsed.
How to check:
Check the well drawdown. The water
level must be at least three feet
above the suction interconnector
during operation.
If the water level is not at least
three feet above the suction
interconnector during operation,
then lower the pump if possible, or
throttle back the outlet valve and
install a water level control.
b) The integral pump check valve is
blocked.
How to check:
Check the pump performance
against the pump curve. See section
9.2 Checking pump performance.
If the pump is not operating close
to the pump curve, pull the pump
from the well and inspect the outlet
section. Remove the blockage,
repair the valve and valve seat, if
necessary. Check for other
damage. Rinse out the pump and
re-install.
c) The inlet strainer is clogged.
How to check:
Check the pump performance
against the pump curve. See section
9.2 Checking pump performance.
If the pump is not operating close
to the pump curve, pull the pump
from the well and inspect. Clean
the inlet strainer, inspect the
integral check valve for blockage,
rinse out the pump and re-install.
d) The pump is damaged.
How to check:
Check the pump performance
against the pump curve. See section
9.2 Checking pump performance.
If the pump is damaged, repair as
necessary. Rinse out the pump and
re-install.
3. The pump
runs, but at
reduced
capacity.
a) The direction of rotation is wrong
(three-phase only).
How to check:
Check for proper electrical
connection in the control panel.
Correct the wiring and change the
leads as required.
b) The drawdown is larger than
anticipated.
Check the drawdown during pump
operation.
Lower the pump, if possible. If not,
throttle back the outlet valve and
install a water level control.
c) The outlet piping or valve are
leaking.
How to check:
Examine the system for leaks.
Repair leaks.
d) The pump inlet strainer or check
valve are clogged.
How to check:
Check the pump performance
against the pump curve. See section
9.2 Checking pump performance.
If the pump performance is not
close to the pump curve, pull the
pump from the well and inspect.
Clean the strainer, inspect the
integral check valve for blockage,
rinse out the pump and re-install.
e) The pump is worn.
How to check:
Check the pump performance
against the pump curve. See section
9.2 Checking pump performance.
If the pump performance is not
close to the pump curve, pull the
pump from the well and inspect.
Problem Possible cause and/or how to check Possible remedy