Not Enough Suction From A Central Vacuum – What To Do?

Nothing is worse than going to vacuum and realizing you have no suction. When you have a central vacuum, several things can cause the suction to be poor. In this post, we will go over what those things are and how to resolve the problem.

When a central vacuum has no or low suction, it could be because of a problem with the motor or a clog somewhere in the hose. There are a couple of things that you can do to fix the vacuum. First, you need to check to see if the power unit has a problem. Then ask yourself the following:

  • Is your vacuum bag over three-quarters full?
  • Are the filters and screen clean?
  • Are the power gaskets installed correctly and functioning?
  • Does your system have more than one motor, and are all your motors functioning?

If your power unit is functioning properly, then you could have a clog in your system. Clogs usually form in the pipes, vacuum head, or hose --where the hose is located impacts how to get the clog out. 

Now that you know those suction problems are caused by either motor problems or a clog, you are probably curious how to fix these problems. We have created a comprehensive guide to explain how to fix your central vacuum.

Closeup of central vacuum cleaner hose plugged in to wall inlet socket. View in to room with central vacuum cleaner.,Not Enough Suction From A Central Vacuum - What To Do?

Why Does My Central Vacuum Have Low Suction?

Cleaning contest: Beautiful bamboo hardwood floor and wool rug with a central vacuum cleaner attached to the wall

 A bad motor or a clog in your system can cause low suction in a central vacuum. Throughout this post, we will explore how you can fix these problems.

Checking The Motor

The very first thing you should do when you notice suction problems is to check the power motor. You do this by disconnecting the piping from the in part of the vacuum. If you feel suction at this point, then your motor is working.

If you don't feel suction, you can try a few things before assuming the motor is bad. First, check your vacuum bag. If it is more than three-quarters full, replace it. A full bag will have a hard time sucking anything up. 

After doing that, check to make sure your filters and screen are clean. Be aware that some systems have secondary filters that can become clogged easily. If there is a lot of debris, you will want to clean or replace filters. This is because dirty filters can make the vacuum suction go down.

If those steps don't work, check to make sure the vacuum's power gaskets are functioning properly and installed correctly. The gasket is usually used to join the bottom-emptying buckets to the actual vacuum. It should be free of wear and cracks.

Finally, check to see if your system has more than one motor. Sometimes the motor will be blowing air but not sucking. To check the motor, plug it in and make sure it runs without stopping for at least 20 minutes. If it's bad, it will need to be replaced. 

How Do I Know If My Central Vacuum Motor Is Bad?

One of the quickest ways to know if your motor is bad is to listen for a clicking noise when you turn it on. A click from your vacuum's motor means that it is dead and needs to be replaced. 

Another sign that your motor is going out is a strong odor. If it smells strong, your motor is about to or has burnt out. You can run the motor until it won't turn on anymore. However, this can cause the thermal mini breaker in the vacuum to go out and need replacement. 

If you think the motor might need to be replaced, check the wire connections in your vacuum. Sometimes the wires in the vacuum aren't connected properly or having issues, and it can look like a bad motor. 

Unclogging Your System

Vacuum pipe connected to central vacuum inlet.

If you have followed the above steps and still have poor suction, you probably have a clog somewhere in your system. To diagnose a clog, first, figure out where the clog is located. It could be in the vacuum head, the hose, or the pipes. 

Vacuum Head

A clog in the head is the easiest to fix. First, you disconnect the head and wands from the main vacuum. Next, you look into the wands and head for any clogs. If you see any, pull the material out. 


To check the hose, plug it into the main vacuum unit rather than a wall valve because clogged pipes will cause a wall valve not to work. This could cause you to think the hose has a clog when it doesn't. Turn the unit on and feel for suction.

If there is no suction, you probably have a clogged hose. To unclog the hose, run something long and stiff, such as a butter knife, through the hose. Make sure to start at the wall end, so you push the clog out rather than into your system. 

Another option is to change the airflow through the hose by connecting the hose handle to the unit. Use your hand to act as a gasket on the end of the hose, let the air move through the hose and remove the clog. 


Unclogging the pipes is a bit more difficult than removing clogs from the head or hose. First, you have to find out where the clog is in the system. You do this by checking to see which low-performing inlet is the closest to the main vacuum.

Then, insert the hose into the inlet and use your hand to create suction on the end of the hose. Let the pressure build for a few seconds, release, and then quickly repeat the process. Do this for about 10 minutes, unless the clog releases sooner. 

Another option is to use a portable vacuum or shop vac hose. You put the hose directly into the inlet with the clog and let the pressure build for a few seconds, then release it. Repeat until the clog is out.

If this doesn't work, you can remove the entire central vacuum unit from the wall and put that hose into the inlet, again using your hand to create pressure to remove the clog.

For Stubborn Clogs

Once you have tried the other methods, you can run a free flow maintenance sheet through the inlet to clear the blockage. The sheet acts as a sail and causes more pressure to build up from the vacuum, which hopefully will remove the clog. 

If you don't know what a free flow maintenance sheet is, check out these on Amazon. As this product is just a suggestion, be sure to check that your sheets are compatible with your specific vacuum.

Click here to check out Free Flow Central Vacuum Maintenance sheets on Amazon!

After all of that, if it still isn't unclogged, you can run electricians fish-tape or use a plumber's snake to try to hook the object. If you don't have fish tape or a plumber's snake, we have included some suggestions below for you to check out.

Click here to see Boeray's 11-foot fish tape on Amazon.

For tough clogs, click here to check out this Ridgid Power Spin snake on Amazon.

If none of the other options remove the clog, you will need to determine the exact location of the clog. For this step, you may want to hire a professional. You will need to really agitate the pipes and potentially cut and reattach the pipes. 

Are Central Vacuums More Powerful?

A common question is whether or not a central vacuum is more powerful than a standard upright vacuum. The answer is yes, central vacuums are more powerful than a standard vacuum.

In fact, they are two to three times more powerful. This suction makes central vacuums vacuum better and can make it take less time to get your house completely vacuumed. As a result, central vacuums are better when you have a larger home because they have more suction. 

How Much Suction Should A Central Vacuum Have?

Young woman cleaning floor using a central vacuum system (also known as built-in or ducted vacuum cleaner).

Water lift is the measurement of a vacuum's suction. Water lift is defined as the amount of negative pressure from atmospheric pressure a unit can develop at zero flow. It is measured by having the vacuum suck water through a tube and measuring how many inches it can pull the water up the tube. 

While all vacuum models can vary in water lift, a standard vacuum usually has about 80 inches of water lift. Water lift varies greatly in vacuums. However, central vacuums range from more than 114 inches to as much as 142 inches.

Quick Recap

Closeup of central vacuum cleaner hose plugged in to wall inlet socket. View in to room with central vacuum cleaner.

In this article, we covered a lot about how to troubleshoot a central vacuum with low suction. A central vacuum can become clogged or have motor problems, and this can affect your suction. 

In addition to covering how to deal with these issues, we also talked about how much suction the vacuum should have and what water lift is. If you found this article informative, click the links below for more interesting articles on this blog. 

How To Find A Leak In A Central Vacuum System

Do Central Vacuums Need To Be Vented?

One comment

  1. It’s nice that you mentioned how a central vacuum having no or low suction could be because of a problem with the motor or a clog somewhere in the hose. I was trying to use our central vacuum earlier but it didn’t have any suction despite being on. I don’t think this is just a simple clog, so I need to ask for a central vacuum in house repair service.

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