10 | EN
Copyright © Liberty Pumps, Inc. 2020 All rights reserved.
6850000C
Pump runs, but does
not turn off.
Pump is airlocked.
Turn pump off and let set for several minutes, then
restart.
Control panel selector switch in Hand position.
Set selector switch to Auto position.
Float switch unable to move to the PUMP OFF
position due to interference with the side of
basin or other obstruction.
Position the pump or float switch so that it has adequate
clearance for free movement.
Control panel failure.
Check control panel.
Defective float switch.
Replace float switch.
Motor stops and then
restarts after short
period but overload
heaters in starter do not
trip.
Pump operating on a short cycle due to basin
being too small.
A larger basin may be required. Consult Liberty Pumps.
Pump cycles too
frequently.
Improper float switch setting.
Adjust float switch setting.
Check valve not installed, is stuck open, or is
leaking.
Install check valve(s); remove check valve and examine
for freedom of operation and proper installation.
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 is 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 (lift height) 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.
Remove obstruction.
Pump is airlocked.
Turn pump off and let set for several minutes, then
restart.
Add baffle to reduce trapped air bubbles.
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 runs periodically
when fixtures are not in
use.
Check valve not installed, is stuck open, or is
leaking.
Install check valve(s); remove check valve and examine
for freedom of operation and proper installation.
Fixtures are leaking.
Repair fixtures as required to eliminate leakage.
Table 2. Troubleshooting Matrix (continued)
Problem
Possible Cause
Corrective Action
