Problem
Discharge valve(s) partially closed or clogged.
Check valve partially clogged.
Pump does not deliver
Incorrect 3-phase motor rotation.
proper capacity.
Total head (lift height) is beyond pump's
capability.
Low liquid level.
Obstruction in pump or piping.
Motor stops and then
restarts after short
Pump operating on a short cycle due to basin
period but overload
being too small.
heaters in starter do not
trip.
Improper float switch setting.
Pump cycles too
frequently.
Check valve not installed, stuck open, or leaking.
Pump runs periodically
Check valve not installed, stuck open, or leaking.
when fixtures are not in
use.
Fixtures are leaking.
Piping attachments to building are too rigid.
Incorrect 3-phase motor rotation.
Pump is being run below minimum head
requirement causing cavitation.
Pump operates noisily.
Foreign objects in the impeller cavity.
Broken impeller.
Worn bearings.
Lower seal has been compromised.
Seal fail light is
illuminated.
Control panel relay sensitivity is incorrect.
Circuit protection underrated.
Current unbalance.
Other appliance on same circuit.
Pump is connected to an extension cord or
Repeated tripping.
wiring is inadequate or compromised.
Improper voltage.
Obstruction in pump.
Incorrect 3-phase motor rotation.
3473000B
Table 2. Troubleshooting Matrix (continued)
Possible Cause
Copyright © Liberty Pumps, Inc. 2019 All rights reserved.
Corrective Action
Check the discharge line for foreign material, including
ice if the discharge line passes through or into cold areas.
Raise liquid level up and down to clear; remove check
valve to remove obstruction.
Correct 3-phase pump rotation direction.
Route discharge piping to a lower level. If not possible, a
larger pump may be required. Consult Liberty Pumps.
Check liquid level.
Remove obstruction.
A larger basin may be required. Consult Liberty Pumps.
Adjust float switch setting.
Install check valve(s); remove check valve and examine
for freedom of operation and proper installation.
Install check valve(s); remove check valve and examine
for freedom of operation and proper installation.
Repair fixtures as required to eliminate leakage.
Replace a portion of the discharge line with rubber hose
or connector.
Correct 3-phase pump rotation direction.
A different sized pump or impeller may be required.
Consult Liberty Pumps.
Clean the impeller cavity.
Consult Liberty Pumps for information regarding impeller
replacement.
Return pump to an authorized repair facility.
Replace lower seal.
Adjust sensitivity dial.
Check rating and replace with proper size.
Check current draw.
Pump requires separate circuit.
Have an electrician check for proper wiring.
Have an electrician check all wiring for proper
connections and adequate voltage and capacity.
Remove obstruction.
Correct 3-phase pump rotation direction.
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