Liberty Pump 404 Troubleshooting [Complete Guide]

This guide on Liberty Pump 404 Troubleshooting will take you through 5 common problems of the drain pump and their solutions.

Liberty Pump 404 Troubleshooting [5 Problems & Solutions]

Before troubleshooting your pump, disconnect the pump from the electric connection. Then, follow the instructions I mentioned below to resolve a specific pump issue. 

1. Pump Won’t Turn On or Shut Off

This drain pump won’t turn on or shut off if there is a problem associated with: 

  • Electric issue
  • Plugged vent or Quick-vent in use
  • Switch is at fault or float switch won’t move freely 

How To Fix: 

First off, ensure you plug the unit into an electric outlet. Though it sounds childish, sometimes we forget about plugging the pump. 

Once you verify the unit is plugged into the outlet, make sure the unit is receiving enough power to activate the unit. I highly suggest having a certified electrician to check all the wiring for proper connections & voltage. 

Next, check the fuse and ensure it doesn’t get blown out. If needed, replace the fuse with a new one. 

Secondly, inspect the vent and ensure there is no restriction in the vent. Verify the vent you use has a diameter of at least 1-¼”. Never use Quick-vent systems as they won’t guarantee proper fixture performance. Also, be sure that the vent pipe has a union to facilitate removal if required. 

Thirdly, your Liberty Pump 404 won’t turn on if the float switch is at fault or gets restricted. To inspect this switch, remove the access cover which is located on top of the unit.  

After removal of the access cover, remove the rubber plug by lifting it up to free up the switch cord. 

Now, remove the float switch from the rod and inspect it. If build-up restricts the float, clean it and ensure it moves freely. Don’t hesitate to replace the float switch if needed. Finally, reinstall the float switch in its place after cleaning or replacing the defective switch. 

2. Pump Runs But Won’t Pump Any Water

Hear a humming noise from the pump but it moves no water? This problem occurs due to one of the following reasons, including: 

  • Restricted or blocked discharge line
  • Check valve is stuck closed or installed improperly 
  • Total lift height goes beyond recommendation
  • The impeller gets clogged 
  • A clogged trap or inlet piping 

How To Fix: 

To begin with, check the discharge line and confirm there is no blockage including ice if the pipe passes through or into cold areas. 

Next, take a look at the check valve which is installed above the union and verify the installation of it is correct. Also, test the freedom of operation of the check valve. It will be better to call a professional to inspect the check valve professionally. 

In addition, the pump won’t pump any liquid or waste water if the total lift height of the system exceeds 11” of height. Try to route the pipe to a lower level to let the unit pump waste water like a champ. 

Moreover, a clogged impeller can also cause the pump to not pump waste water. In this case, you must clean the impeller to let the unit operate properly. To do so, disassemble the receiver and remove the bottom base of the unit. Then, clean the impeller area thoroughly.  

Finally, your Liberty Pump 404 will struggle to pump if the inlet piping or its trap gets restricted. To fix this issue, inspect the inlet piping and clean it to let the liquid pass through it like a charm. Don’t forget to check the trap which is located between the fixture and pump.

3. Pump Short Cycles

The pump will keep turning on and off repeatedly or short cycles because of a plugged vent, defective switch, or improperly installed check valve. If you don’t resolve the short cycling issue, it will shorten the lifespan of the unit. It may even bring ultimate damage to the unit.  

How To Fix: 

Start by inspecting the vent and ensure it’s not plugged. Be sure that an unrestricted vent at least 1-¼”  in diameter is in use. 

Next, take your eyes at the float switch if the pump keeps coming on and off. I already mentioned the way of troubleshooting the switch. Just take off the access cover and verify the float is moving freely. Clean the switch if buildup restricts it. 

Lastly, remove the check valve and test the freedom of operation and proper installation. 

4. Pump Runs Periodically When Fixtures Are Not In Use

It typically occurs if the faucets are dripping. To fix this problem, repair the faucets to eliminate water drippings. 

Turns out, improper installation of the check valve can cause this pump issue. Regarding this, I recommend you check the check valve to ensure it works properly. 

5. Water or Soap Suds Come Out of Vent Pipe

You will experience this issue if the float switch is at fault or the rate of in-flow exceeds pump output.

How To Fix: 

At first, verify the float switch is moving freely with the rise of liquid in the sump pit. If needed, remove the tank cover and inspect the float. If cleaning the float switch doesn’t bring any luck, replace the switch. 

Next, install a valve on the inlet to reduce the rate of inflow to prevent the drippings from coming out of the vent pipe. 


That’s it… Electric appliances are not beyond malfunction. Fortunately, this guide broke down all the common problems you will experience with your Liberty 404. Just follow the troubleshooting steps and resolve the pump issue. 

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