Sump Pump Running but Not Pumping | A Quick and Easy Fix

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The sump pump is the last line of defense that can save your basement from flooding waters. But just like any other equipment, it isn’t immune to breaking down or malfunctioning. One of the common problems that homeowners face with their sump pumps is that they can suddenly stop pumping while running. So, here are the reasons why this can happen:

  • Mechanical defect with the float
  • Faulty check valve
  • Clogged inlet and discharge line
  • Damaged impeller
  • Wrong pipe sizes

Now that you know the possible scenarios that can restrict the functions of your pump, you need to know how to locate and diagnose the problem. So, how do you diagnose it?

Why is Sump Pump Running But Not Pumping Water

Before you solve the problem, figuring out what’s causing the problem is essential but tricky. Here is a list of possible causes:

Sump Pump Running but Not Pumping

Mechanical Defect with Float Switch

When the water level inside the pit rises up, the float switch rises along with it and signals the sump pump to start removing water. However, if the switch is unable to relay any signal, then the pump will not discharge any water. This can happen due to a few reasons:

  • The switch can be faulty or defective.
  • The position of the pump inside the pit can shift. This can cause the switch to get itself jammed along the edges of the pump.
  • The switch can get stuck by debris present in the sump water or by dangling wires, therefore, unable to rise and activate the pump.

Solution – First, you need to visually inspect the float switch.

  • In the case of faulty equipment, you’re only left with the option- to replace the float switch.
  • If the pump has tilted, then you need to re-adjust it back to vertical alignment. However, before you do that, the sump pit has to be empty first.
  • If the float ball is obstructed by any object, then take it out of the way. After that, try lifting the float with your hand and check if the pump is receiving any signal to activate or not. If it does, then add water to the pit and let it pump.

Damaged Check Valve

The check valve is a crucial component of the drainage system. If your float switch is working properly, then the problem may lie with the valve. It is attached to the discharge pipe. When the water is pumped out by the sump pump, a portion of water always gets held back in the pipe. The valve prevents the backflow of water into the pit. So, if the valve is damaged or is missing, the water will flow back into the pit and reverse the direction of the impeller.

Solution – To inspect the valve, you must unplug the sump pump before checking. If you notice that your check valve is missing, then you can have it installed. And, if you happen to see cracks or any other signs of damage, then it is best to replace it.

Discharge Line Blockage

As we mentioned earlier, the discharge line is an essential part of the system. In fact, if the water doesn’t flow smoothly through the pipes, the entire system can break down. Sadly, there are a few reasons why the flow can get disrupted.

  • The water that gets collected in your sump pit during the rainy season has a high concentration of debris and gravel in it. They can cause the discharge pipe to get clogged. As a result, the flow of water will get restricted, and the pump will not be able to empty the pit.
  • Similar to the clogging of the discharge pipe, the debris can also block the inlet line as well.
  • During the coldest of months of winter, it is quite common for the water in the pit to freeze. If the pump takes in any icy water, it can freeze both the inlet and pipe and the pump will stop pumping.

Solution – To look for blockages, then:

  • First of all, check the outer end of the discharge pipe for any debris. If you find any, you can remove them with your hand by using a pair of rubber gloves or a screwdriver if you find it hard to remove them.
  • If the discharge line is clear, then take a look at the inlet line. Remove any visible clogs and clean the pipe properly.
  • In the case of ice, you can thaw it by pouring hot water into the line.

To make sure that the pipes are clear of any debris, pour water through the disconnected lines. Remember, while you are inspecting, the pump should be turned off.

Malfunctioning Impeller

The impeller of the sump pumps is the heart of the entire operation. It draws the water into the pump and directs it outside through tubes. Usually, the pumps have a screen in front of the impeller to prevent the debris from jamming the blades. However, sometimes tiny dirt particles make their way through the screen and get lodged onto the blades. If this continues for a period of time, the impeller will begin to malfunction. The blades will stop spinning, and the pump cannot pump any more water.

Solution – To clean the impeller, you need to dismantle the pump out of the pit. Then, you need to take off its casing and reach out for the screen and then the impeller.

While removing the casing, if you notice that the impeller has become unhinged or has fallen off, you can re-thread it back. However, if there are any damages to the impeller, then you will need to replace it.

Wrong Pipe Size

One of the common mistakes made during installation is getting the wrong pipe size. If the diameter discharge pipe is too small, then it will add strain to the pump and reduce its efficiency.

SolutionEvery sump pump model has its own set of specifications about the size of the pipe it needs. If you believe that the pipe isn’t of the right size, then re-measure its diameter. If it is small, then you can replace it with the right size.

Is It Time for A Replacement?

Age can be one of the major reasons behind the malfunctioning of your pump. Normally, a pump has a life expectancy of 10 years. However, there are some that can run on for 15-20 years. However, after a rigorous amount of wear and tear, the pump can get overwhelmed and eventually give out. So, after ticking off all the other possible reasons, if your pump is still not working, then it’s time for a new one.

Steps to Maintaining the Pump`

Regularly maintaining can increase the sump pump life span and also improve its efficiency. The frequency of how often you clean the pump and the pit depends on how much it is being used. Nevertheless, it’s a good habit to clean it every 6 to 9 months.

Here’s the step-by-step procedure:

  1. Before you begin, ensure that the sump pump is switched off and then unplug it.
  2. Disconnect the discharge tube and then remove the pump from the sump pit.
  3. Once you have taken the pump out, jump inside the pit and inspect the switch. Look for any obstacle in its path.
  4. While you are in there, clean the sump pit and the check valve by using a pair of gloves and a rag. Remove the dirt, gravel, and sludge from the bottom of the basin and then wipe down the walls as well.
  5. After you are done, get out of the pit. Now, you can focus on the pump. Clean the outer sides of the pump. If there is rust on the surface, then take a look at the instruction manual. See if you can apply oil or any other products to get rid of it.
  6. Next, clean the inlet line and then remove the casing of the pump. Usually, there is a lid underneath that allows you to clean the insides.
  7. Before you inspect the impeller, remove the screen covering it, and then wash it.
  8. Later, take the impeller out. Look for any signs of damage or clog on it. Clean out the blades.
  9. After all the above tasks have been done, reassemble the parts back together and then re-install the pump into the pit. Reconnect the discharge line and then switch on the pump.
  10. Pour in clean water until the float bulb rises, see if the pump starts pumping water out.

Sump pump humming but not pumping 

Having a low humming sound coming out of the pump is quite normal. But if you notice that the water level is not going down, here are a couple of reasons why.

  • Airlock – This usually happens during the warmer season, water inside the sump pit dries out allows the air to get collected in the vent hole located at the base. The built-up air can restrict the flow of water and cause a humming sound. Try switching on and off the pump about three to four times, by using a float switch. If the situation remains the same, there may be a clog in the pipes.
  • Frozen pipes– during winter, the residual water in the discharge pipe can freeze over and block the passage. For this, use an infrared heater to melt down the ice. Make sure to look for any possible blockages. Also, if the drainage system has more than three 90-degree elbows, it can significantly reduce the flow of water. To avoid this, you can replace a 90-degree elbow with a 45-degree elbow. This will allow the water to flow out smoothly.

Why Is My Sump Pump Humming? 

If you are hearing a sound, that is out of the ordinary, coming out of your pump, know that there is something wrong with it. There can be a number of reasons behind the noise.

  • Improper installation– when you are installing the check valve, ensure that it is properly installed. If it is done incorrectly or if it is in a closed position, it can result in a humming sound. So ensure that the arrow on the valve is pointing in an upward direction towards “discharge” and not at “pump”.
  • Clogged impeller – if you are often using your sump pump, many times, the impeller gets jammed after running for a while. It draws in water from the sump pit and then pumps it out. Sometimes the debris gets caught in the blades of the impeller, causing it to produce a humming sound. So, make sure that you clean the insides of the pump properly. Also, check the blades carefully for cracks or broken parts.

How do you fix a humming sump pump?

There are several reasons behind the humming of your sump pump. So, to prevent it from being noisy, you need to first assess the pump, pinpoint the problem and then troubleshoot it.

  • Check the vent hole, see if there is an air lock or debris that is blocking the pathway. If so, then remove the debris and clear the channel.
  • Make sure that the orientation of the check valve is correct. If the humming sound persists, install a spring-loaded check valve instead. Also known as a silent valve, it reduces the sound caused by water in the pipes.
  • Clean the moving mechanical parts of the pump regularly. Remove any debris attached to the impeller. Install a filter, if possible, it will make the cleaning process easier.
  • If your sump basin is open, install a well-insulated airtight cover over it. It will not only keep the unpleasant smell away but also the humming sound as well.

How Do You Know That Your sump Pump Has Stopped Pumping?

Unless you are constantly taking a peek into your sump pit, it is difficult to find out whether your pump is pumping water out or not. This can become a nightmare for you, especially in the middle of a storm, when the water levels will continue rising and flood your basement, without your knowledge. So, to help you monitor the status of your pump- you can install a sensor onto the float switch that will notify you by beeping when the water level is beyond the danger line.

Should a sump pump have standing water in it?

Having a small amount of water in the pit is completely normal. However, if there is too much water in the pit or if it’s full, then it is an entirely different story. In this case, either there is continuous water seepage or your pump is malfunctioning.

If the water is constantly flowing into the pit, then

  • Your water table may be too high. For this, you can raise the pit to a greater height. You can also upgrade your system and install another sump pump at a different location in the basement.
  • If the discharge pipes are blocked, they cannot expel water out. De-clog the pipes and see to it that the water can flow freely
  • In the case of a busted pipe or broken sprinkler system, replace the broken section, if possible.

If your pump is not working, then

  • Look for any mechanical defects in the device
  • Check if the float switch is working or is jammed

Final Words

Once you know your way around the sump pump, it’s pretty easy to resolve any clog-related issues. You can do so without relying on any professional help. All you need to do is simply follow the steps, maintain your sump pump, and most of your problems can be solved. However, no amount of poking, prodding, magic, or alchemy can revive a pump that is either dead or about to die. So, the blueprint goes something like this- try to find and fix. If it doesn’t work- take the hit and get a sump pump.

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