Troubleshoot Pump Problems


Troubleshoot Your Pond Pump

When your pond pump stops working, your fish and biological filter are at risk. Depending on many factors, you may have as little as a few hours to avoid a catastrophe. Hopefully you have planned ahead and you have a spare pump ready to go anytime the need arises. With the following information we hope to be able to help you troubleshoot and get your pump back to pumping water thus saving you effort, frustration, and possibly the expense of a new pump.

These steps are specific to submersible pond pumps. For external pumps, refer to the manufacturer’s literature. You can find the Sequence Pump manual for the 4000 series here (1MB PDF file will open in a new tab or browser window).


Whether the pond pump needs to be repaired or replaced or something else, first you must determine the problem. The first step is to observe the pump to see exactly what is happening. Has the pump completely stopped, or is there a hum, or maybe a loud noise?


If there is a loud sound coming from the pump the issues could be:

A. Vibration against a hard surface like a skimmer.
Placing something like a foam mat under the pump may be enough to solve this.
B. There may be debris around the pump impeller or the impeller itself may be broken.
Inspect the intake area thoroughly.
C. A loud grinding sound may indicate the bearings have failed.
The pump will need to be replaced.


If there is a hum still coming from the pump but no flow the issue could be:

A. A clog in the intake or in the discharge pipe.
Inspect the pump intake to ensure that it is free from debris. If clean and the problem persists, try placing the pump in a tub of water with no pipe attached and see if it works. If so, you will need to clean your plumbing lines.
B. Vapor lock (air in the pump). Vapor locks can be common when reinstalling a pump after cleaning it.
Tilt the pump on its side and back and forth while submerged. You may see bubbles rise from the pump. If possible, do this with the pump on.
C. The capacitor may have failed.
A new pump is needed.


If the pump does absolutely nothing the issue could be:

A. Engagement of the thermal overload protection.
Most submersible pumps feature a thermal overload protection to minimize damage to the pump should it overheat. There are multiple reasons that a pump could over heat (such as clogs or too much resistance), but the most common is lack of complete submersion, especially if the pump is in a skimmer. If a skimmer net/basket/pad gets clogged the water level in the pump chamber can drop. When this happens the pump will shut off. When it cools off it can restart. (Note that when the pump shuts off the skimmer will fill back up, so the fact that the skimmer is full when the pump is off does not indicate that this was not the problem). Give the pump time to cool down, this may take up to an hour. Then try again, ensuring that the pump stays submerged. Repeated engagement of the thermal overload protection can damage the pump. Keep your skimmer clean.
B. Problem with the GFCI.
See if your GFCI has tripped. If so, reset it and try again. If it trips again you either have a bad pump, faulty GFCI, or some other device using the same GFCI is the problem. Test the pump on another GFCI.
C. No electricity to pump.
Check the outlet with another electrical device and/or check the pump on another outlet that uses a different circuit.


If the pump flow has lessened the issue could be:

A. This is almost always not a pump issue, instead there is a clog.  This clog could be on the intake side of the pump such as a pre-filter or a clog in the tubing.
B. A damaged impeller can also cause a reduced flow.  Inspect the impeller.


Proper care of your pump is the key to a long pump life. Inspect your pump intake regularly for restrictions. Anytime you see the flow reduced, check the pump ASAP. If you are unsure how to thoroughly clean your pump, refer to the instructions that came with it or contact AquaNooga. Never pull or carry the pump by the cord. And, of course, start with a good-quality pump that is well-suited for your application.

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