Problem
Tripped circuit breaker, tripped GFCI, blown fuse,
or other interruption of power.
Improper voltage.
Defective motor.
Low line voltage.
Pump does not start.
Float switch unable to move to pump ON
position due to interference in basin or other
obstruction.
Insufficient liquid level.
Defective float switch.
Obstructed impeller or volute.
Loose wiring connections.
Discharge line blocked or restricted.
Check valve stuck closed or installed backward.
Gate or ball valve closed.
Pump runs or hums, but
does not pump.
Total head beyond pump's capability.
Obstructed impeller or volute; clogged inlet
screen.
Pump airlocked.
Pump runs periodically
Check valve not installed, stuck open, or leaking.
when fixtures are not in
use.
Fixtures leaking.
Pump airlocked.
Float switch unable to move to pump OFF
Pump runs, but does not
position due to interference with the side of basin
turn off.
or other obstruction.
Defective float switch.
Improper float switch setting.
Pump cycles too
frequently.
Check valve not installed, stuck open, or leaking.
7229000D
Table 1. Troubleshooting Matrix
Possible Cause
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Corrective Action
Reset tripped circuit breaker, reset GFCI, replace blown
fuse with properly sized fuse, check that the unit is
securely plugged in, investigate power interruption.
Have an electrician check all wiring for proper
connections and adequate voltage and capacity.
Consult Liberty Pumps.
Check voltage. If under 108 V, check wiring size.
Remove extension cord, or use with heavier gauge.
Position the pump or float switch so that it has adequate
clearance for free movement.
Verify the liquid level is allowed to rise enough to activate
float switch.
Replace float switch.
Remove obstruction.
Check and tighten all connections.
Check the discharge line for foreign material, including ice
if the discharge line passes through or into cold areas.
Remove check valve and examine for freedom of
operation and proper installation.
Open gate or ball valve.
Route piping to a lower level. If not possible, a larger
pump may be required. Consult Liberty Pumps.
Remove obstruction.
Turn pump off and let set for several minutes, then restart.
Clear anti-airlock hole.
Install check valve; remove check valve and examine for
freedom of operation and proper installation.
Repair fixtures as required to eliminate leakage.
Turn pump off and let set for several minutes, then restart.
Position the pump or float switch so that it has adequate
clearance for free movement.
Replace float switch.
Adjust float switch setting.
Install check valve; remove check valve and examine for
freedom of operation and proper installation.
7 | EN