Liberty Pumps LGV Serie Manual De Instalación página 11

Problem
Pump cycles too frequently.
Pump does not start and overload
heaters trip.
Pump operates noisily.
Pump runs or hums but does not
pump.
Motor stops and then restarts
after short period but overload
heaters in starter do not trip.
7550000F
Table 3. Troubleshooting Matrix (continued)
Possible Cause
Improper float switch setting.
Check valve not installed, stuck open, or leaking.
Unintentional ground.
3-phase motor winding failure.
Obstructed impeller or volute.
Piping attachments to building are too rigid.
Incorrect motor rotation.
Pump is being run below minimum head
requirement causing cavitation.
Foreign objects in the impeller cavity.
Broken impeller.
Worn bearings.
Discharge line blocked or restricted.
Check valve is stuck closed or installed
backward.
Gate or ball valve is closed.
Total head (lift height) is beyond pump's
capability.
Obstructed impeller or volute.
Pump is airlocked.
Capacitor failure in control panel.
Stuck/defective motor contactor in control
panel.
Pump is not seated correctly in guide rail base.
Pump may be operating on a short cycle due to
basin being too small.
Water returning to basin due to leaking check
valve.
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Corrective Action
Adjust float switch setting.
Install check valve(s); remove check valve and
examine for freedom of operation and proper
installation.
Turn off power and check motor leads for
possible ground.
Check resistance of motor windings. All three
phases should have the same reading.
Remove obstruction.
Replace a portion of the discharge line with
rubber hose or connector.
1-phase: verify capacitor wiring in Figure 1, else
consult factory.
3-phase: correct pump rotation direction. Refer
to section 3-Phase Pump Rotation
Verification.
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.
Check the discharge line for foreign material,
including ice if the discharge line passes through
or into cold areas.
Remove check valve(s) 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.
Add baffle to reduce trapped air bubbles.
Check capacitors and replace if needed.
Replace motor contactor.
Lift pump and re-position.
A larger basin may be required. Consult Liberty
Pumps.
Replace check valve.
11 | EN