Grundfos SP Series Installation And Operating Instructions Manual page 16

Problem
2. Pump runs but
does not deliver
water.
3. Pump runs but at
reduced capacity.
16
Possible cause/how to check
a) Groundwater level in well is too
low or well is collapsed.
How to check:
Check well draw-down. Water level
should be at least 3 ft. above pump
inlet during operation.
b) Integral pump check valve is
blocked.
How to check:
Check the pump's performance
against its curve; see section
6.2 Checking pump performance
on page 14.
c) Inlet strainer is clogged.
How to check:
Check the pump's performance
against its curve; see section
6.2 Checking pump performance
on page 14.
d) Pump is damaged.
How to check:
Check the pump's performance
against its curve; see section
6.2 Checking pump performance
on page 14.
a) Wrong rotation (three phase only).
How to check:
Check for proper electrical
connection in control panel.
b) Draw-down is larger than
anticipated.
Check draw-down during pump
operation.
c) Discharge piping or valve leaking.
How to check:
Examine system for leaks.
d) Pump strainer or check valve are
clogged.
How to check:
Check the pump's performance
against its curve; see section
6.2 Checking pump performance
on page 14.
e) Pump is worn.
How to check:
Check the pump's performance
against its curve; see section
6.2 Checking pump performance
on page 14.
Possible remedy
If water level is not at least 3 ft. above
pump inlet during operation, then
lower the pump if possible, or throttle
discharge valve and install water level
control.
If the pump is not operating close to
the pump curve, remove pump and
inspect discharge section. Remove
blockage, repair valve and valve seat
if necessary. Check for other damage.
Rinse out pump and re-install.
If pump is not operating close to the
pump curve, remove pump and
inspect. Clean strainer, inspect
integral check valve for blockage,
rinse out pump and re-install.
If pump is damaged, repair as
necessary. Rinse out pump and
re-install.
Correct wiring and change leads as
required.
Lower the pump if possible. If not,
throttle discharge valve and install
water level control.
Repair leaks.
If not close to the pump curve, remove
pump and inspect. Clean strainer,
inspect integral check valve for
blockage, rinse out pump and re-
install.
If not close to pump curve, remove
pump and inspect.