Install Instructions

5. Install a union or other means of separating the discharge pipe just above the floor to facilitate removal of the

pump if necessary. A check valve is recommended just above or in place of the union to prevent the

backflow of water after each pump cycle.

6. If a check valve is used, a 1/8” anti-airlock hole should be drilled in the discharge pipe just above the

pump’s discharge outlet to prevent pump “airlock”.

7. Connect additional pipe as necessary to direct the discharge to the desired location. Discharge should be kept as

short as possible with a minimum number of turns. Check all connections for security.

8. For added protection, consider the addition of a back-up pump such as Liberty’s SJ10 SumpJet, as well as an

alarm such as Liberty’s ALM-2 in applications where loss of pump function could result in property damage. If

an alarm is used, it must be connected to a separate electrical circuit.

Figure B.

Check Valve

or Union

Drill 1/8” anti-

airlock hole.

Water spray is

normal.

Is my pump air-locked? What is an anti-airlock hole?

Air-lock is a term used to describe when air gets trapped in the volute/impeller area of a pump and cannot escape due to

the water column above the check valve on the discharge line. When the pit fills with water and the pump is called to

activate, the impeller spins in this pocket of air and cannot prime. “My pump runs, but does not pump anything” is the

symptom when this happens. An anti-airlock hole allows this trapped air to escape, allowing the pump to prime and start

pumping.

Liberty provides an integral anti-airlock hole in the volute housing of submersible pumps. Water spray from this hole is

normal while the pump is in operation. Bleeding off the air could take from several seconds to more than a minute once

the pump starts. To speed or assist with air bleed in the event of airlock, the addition of a 1/8” hole in the discharge pipe

is recommended. This hole should be no more than 1/8” diameter and drilled low on the pipe – just above the threaded

connection to the pump discharge. See Figure B above.

Submersible Pump

Pedestal Pump