3473000C
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11 | EN
Pump does not deliver
proper capacity.
Discharge valve(s) partially closed or clogged.
Check the discharge line for foreign material, including
ice if the discharge line passes through or into cold areas.
Check valve partially clogged.
Raise liquid level up and down to clear; remove check
valve to remove obstruction.
Incorrect motor rotation.
1-Phase: Verify capacitor wiring in Figure 1, else consult
factory.
3-Phase: Correct 3-phase pump rotation direction. Refer
to section 3-Phase Pump Rotation Verification.
Total head is beyond pump's capability.
Route discharge piping to a lower level. If not possible, a
larger pump may be required. Consult Liberty Pumps.
Low liquid level.
Check liquid level.
Obstruction in pump or piping.
Remove obstruction.
Pump runs or hums, but
does not pump.
Discharge line is blocked or restricted.
Check the discharge line for foreign material, including
ice if the discharge line passes through or into cold areas.
Check valve stuck closed or installed backward.
Remove check valve(s) and examine for freedom of
operation and proper installation.
Gate or ball valve is closed.
Open gate or ball valve.
Total head is beyond pump's capability.
Route piping to a lower level. If not possible, a larger
pump may be required. Consult Liberty Pumps.
Obstructed impeller or volute; clogged inlet
screen.
Remove obstruction.
Pump is airlocked.
Turn pump off and let set for several minutes, then
restart.
Add baffle to reduce trapped air bubbles.
Clear anti-airlock hole.
Capacitor failure in control panel.
Check capacitors and replace if needed.
Stuck/defective motor contactor in control
panel.
Replace motor contactor.
Pump is not seated correctly in guide rail base.
Lift pump and re-position.
Pump operates noisily.
Piping attachments to building are too rigid.
Replace a portion of the discharge line with rubber hose
or connector.
Incorrect motor rotation.
1-Phase: Verify capacitor wiring in Figure 1, else consult
factory.
3-Phase: Correct 3-phase pump rotation direction. Refer
to section 3-Phase Pump Rotation Verification.
Pump is being run below minimum head
requirement causing cavitation.
A different sized pump or impeller may be required.
Consult Liberty Pumps.
Foreign objects in the impeller cavity.
Clean the impeller cavity.
Broken impeller.
Consult Liberty Pumps for information regarding impeller
replacement.
Worn bearings.
Return pump to an authorized repair facility.
Table 3. Troubleshooting Matrix (continued)
Problem
Possible Cause
Corrective Action
