Nortek Security and Control KB

My vacuum doesn’t have as much suction as it used to. What’s wrong?

Most central vacuum systems have two filters that protect the motor from dirt and debris – the main cloth bagor sponge filter, and a smaller screen filter. Some older model vacuums employed a sponge filter instead. These older models did not have a secondary filter.

When these filters become clogged, the air flow inside the unit is compromised and the suction power will drop off significantly. To return your vacuum’s suction power, these filters need to be cleaned.

The first step in determining whether or not it is a problem with your vacuum – and not a clog somewhere – is to test the suction at the canister itself. To do this, follow these steps:

  1. Make sure all inlets in the house are closed.
  2. Locate the covered port on the side of the vacuum canister used to attach a hose (for cleaning out your car or surrounding area where the vacuum sits).
  3. Remove the cover from this port and turn your vacuum canister on using the On/Off switch.
  4. Put your hand over the open port and see how strong the suction is.
  5. If the suction is strong, the problem is not the canister. More than likely you have either a broken pipe or clog in your line somewhere.
  6. If the suction is less than it should be, then either the filters need cleaning or your motor needs to be repaired.

If you determine that the canister has sufficient suction, then you may want to contact a local dealer to have them check out your piping system for leaks, breaks, or clogs. You can locate a dealer in your area by visiting our website at:

If you determine that the loss of suction is at the canister, then continue with the rest of this procedure.

If your system has a sponge filter, simply replace the filter. Canisters with sponge filters do not have the secondary, or flock, filter. Contact your local dealer for a replacement filter.

The cloth bag is the most commonly used type of main filter system and keeps the majority of debris from clogging up the motor. Smaller particles, like fine sand or dust, may pass through the cloth bag and get sucked toward the motor. It is the job of the flock filter to stop these smaller particles from entering the motor. When this filter becomes clogged, the suction on your unit will definitely drop off.

As most of the current model vacuums have the bucket on the bottom, these instructions are geared towards those. However, if your canister has the bucket/bag on top, you can still follow these instructions as they apply to both types – it is just a different view.

To access and clean the flock filter, follow these steps:

  1. Remove the debris bucket and/or disposable bag.
  2. If you have a disposable bag, there will also be a plastic cone which funnels the debris toward the disposable bag. Remove this cone.
  3. Before removing the cloth bag filter, check to see how far up inside the canister it sits. It is important that you replace it in the same location when you put it back.
  4. Slide your hand up inside the canister between the bag and the inside of the canister. You will find the bag is attached to a stiff ring at the top.
  5. Grab this ring and push it toward the middle/inside of the canister. As you do so, the ring will collapse. Remove the cloth bag and set it aside.
  6. Take a flashlight and look up inside the canister. At the top you will see a small screen filter – this is the flock filter.
  7. Using a soft cloth or soft bristled paint brush, clean off the flock filter.
  8. Take the cloth bag filter outside and shake it vigorously to remove any dirt and debris that may be stuck to it. If you feel that the cloth bag should be cleaned with water, you must ring it out completely and then let it air dry for 48 hours before putting it back in the canister. Failure to do this will cause severe damage to your motor.
  9. To put the cloth bag back in your canister, press opposite sides of the ring together and hold it with one hand.
  10. Place the bag/ring back up inside the canister at the same location you removed it.
  11. Release one side of the ring and let it make contact with the canister.
  12. Pull the side of the ring you are still holding back across to the other side. As you do so, the ring will pop back into place.
  13. If your system has a disposable bag, put the plastic cone back into place.
  14. Re-attach the bucket and disposable bag, if one is used.
  15. Re-test your vacuum at the canister.
  16. If the suction is still low, you may need to call a dealer and have them check out your system.
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