Zoeller Battery Backup Sump Pump Troubleshooting

Zoeller Battery Backup Sump Pump Troubleshooting

This is a complete guide on Zoeller Battery Backup Sump Pump Troubleshooting. What I am going to cover: 

  • 9 common problems of the Zoeller Battery Backup Sump Pump
  • Solutions to those issues
  • Answer to Frequently Asked Questions

Without further ado, let’s dive in.

Note: This troubleshooting guide will be helpful for homeowners who owns any battery backup sump pump mode from Zoeller like Zoeller Aquanot 507.

Table of Contents

Zoeller Battery Backup Sump Pump Troubleshooting [9 Problems & Solutions]

Let’s explore solutions to the common problems of your Zoeller Battery Backup Sump Pump. 

1. Charging and Charged LED’s Alternate Frequently

When you install this sump pump for the first time, you will observe two LEDs (Charging and Charged) on the controller are constantly flashing. Is that okay?

The answer is- Yes. 

These two lights are supposed to be flashing at all times while you plug the control module in. 

In short, this is not a problem at all and you don’t need to take any corrective actions.  

2. DC Pump Won’t Run

The DC Pump won’t run due to: 

  • 15 amp fuse in the line from pump to switch gets blown out
  • Improper wire connections
  • All wire terminal points get corroded
  • Low battery or the charge of it goes down 

How To Fix: 

To begin with, I recommend you check this little doohickey if the pump won’t turn even though it receives power: 

The doohickey houses a 15 amp fuse

It houses a 15 amp fuse. If it gets blown out, your battery backup sump pump won’t come on. To resolve this issue, just replace that blown out fuse with a new 15 amp Littelfuse type 3AG, series 311 fuse. 

In addition, don’t forget to check all the wire connections on the sump pump. Ensure every wire connection is secure and tight.  

Also, don’t forget to inspect the terminal points for corrosion. If needed, clean those wire terminal points. 

Lastly, the battery of the pump can also be a culprit. If I were you, I would take the battery to a battery specialist to have it checked professionally. 

3. Pump Runs But It’s Pumping Very Little or No Water

Your battery backup sump pump like Zoeller Aquanot 507 will operate but it will pump little or no water due to low battery. 

Or, the battery gets completely dead… 

Turns out, weak batteries are also responsible for this issue. 

How To Fix: 

First off, check for low battery. I recommend you recharge the battery if the battery is low. The battery will recharge if the Red power ‘on’ light indicates power has been restored and the float switch is in Off position. 

Secondly, I highly suggest you replace the dead battery with a full recharged battery if you want to use the pump immediately. 

Keep in mind; Depending on varying conditions, the pump will continue to run with weak batteries without enough power to remove water. 

Of course, you can recharge the weak batteries. But the heck is- those batteries might fail to store sufficient energy for full service. 

If you use this pump frequently, it will be better to check the battery by a certified battery dealer. 

4. Pump Cycles Too Frequently

The sump pump turns on and off frequently? If this is the problem you are going through, I bet you know what it calls aka short cycling.  

Short cycling is a result of improper position of the rubber stops on the float rod. 

Turns out, an undersized sump pump that fails to handle your basement water will turn on and off continuously. 

How To Fix:

I recommend you check the position of the rubber stops on the float rod. If required, adjust the upper rubber float stop according to your need. 

Nonetheless, size up the sump pump according to your pumping demand to avoid short cycling. 

5. Float Switch Is ‘On’ Position But Pump Won’t Run

Zoeller Sump Pump won’t run even though the float switch is in the On position. It happens when the impeller gets restricted with dirt & debris. Releasing the obstructions from the impeller will help you fix this issue. 

How To Fix: 

Remove the sump pump from the basin. Then, take the impeller out of the sump pit. 

To get rid of debris from the impeller, use a small brush to remove dirt from the discharge hole and the check valve. Don’t forget to rinse the impeller with clean water. 

Once you clean the impeller, let it dry. Lastly, attach the impeller to the sump pit and walk away. 

6. The Unit Is On But Pumps Water Intermittently

This generally happens because of air lock. 

Take a note of the flow of water incoming to the sump. If water is entering the sump at a high velocity creating turbulent conditions, I bet a mixture of water and air may cause a partial or complete air lock. 

When air lock occurs, it will reduce or stop the flow of water to the discharge pipe. 

How To Fix:

To correct the airlock, just divert the stream of water against the wall of the basin. I highly suggest the following tutorial that will help you fix the air-lock issue: 

7. Water Level Stays High. DC Pump Continues To Run

If the battery remains low, the DC pump won’t get enough pumping power to pump the water. But it will get the power to run. As a result, the water level in the basin will remain high. 

How To Fix: 

Recharge the battery until it is full of charge. If there is still a high level of water in the basin after the power has been restored, check the primary pump. Service the pump if required. 

8. Alarm Sounds During Battery Recharge Cycle

Resetting the alarm will help you fix this issue. To reset the alarm, press the reset button on the control module for maximum 3 times. If it doesn’t bring any luck, replace the battery. 

9. Alarm Doesn’t Sound When Pump Runs

Generally, the pump needs to run for 3 seconds before the alarm has made the beeping noise. 

So, ensure you run the pump for at least 3 seconds. If the alarm doesn’t sound after that, verify the alarm is not set to silent mode. 

Next, take a look at the connection between the green and the blue connector on the white wire. Make sure that the metal spade has not missed its target. 


Why is my sump pump battery backup not working?

Here are some reasons that prevent your sump pump battery backup from working: 

  • Install the switch improperly
  • Dirty impeller
  • Incorrect wiring
  • Air lock

How do I know if my battery backup sump pump is working?

It’s simple. Just observe the battery indicator light and ensure it’s green, which lets you know: your battery backup sump pump is in working state. Luckily, every battery backup sump pump has an alarm system which alerts you when the battery reaches its end life cycle.

How do I reset my Zoeller pump?

Unplug the Zoeller Sump Pump from the electric connection for 30 seconds. Then, insert the plug into the electrical outlet and have your sump pump reset.


Like any electrical appliances, the sump pump also starts malfunctioning over time. And this guide broke down all the common problems of the sump pump. Just follow the troubleshooting steps I mentioned and resolve the issue. 

However, if you are not comfortable to work with messy water and electricity, it will be best to call a professional to do the task for you. 

Happy Plumbing!

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