Vacuum Lost Suction

Many vacuums have a control to lower the suction force for vacuuming area rugs or other things that could readily be sucked up.

• You may think your unit has a major problem, and the problem is simply the suction control is turned to low.
• Check to see if it is open. If it is, close it and see if performance improves. If things are back to normal, you're done.
• If you still aren't getting suction, move to the next cause.

Check the hose for obstructions.

You may need to detach it from the machine and try looking through it first. But...

• Sometimes clogs don't show up fully when you look through the hose
• You may find you can't get the hose straight enough to look through, especially if it is long.
• There may be an angled fitting on the end of the hose, which prevents looking through it.
• So, follow up the visual inspection (which is valuable for checking the condition of the hose such as holes) with the physical check described next.

You can use a piece of stout wire (or a wooden dowel) to make sure there is no clog in the hose,

• A stout wire, like a metal clothes hanger that has been opened up, can be used. It has the right balance of rigidity and flexibility.
• Make sure you bend the end of the wire over into a small loop, so that it can't puncture your hose, and it will slide through more easily.
• Push the wire through the hose several times. There may be clogs that can only be dislodged in several tries. Rotate the wire if possible when you do this.

Check to see that it has no holes or cracks.

• Make sure you flex and stretch the hose thoroughly.
• Sometimes, a crack will not show up until the hose is stretched.
• Do this test while the vacuum is operating as you will likely hear a leak more easily than you might see it.
• If the hose is good, go to the next cause.

A very simple cause of low suction is an overfilled vacuum bag. If your vacuum uses a bag check to see if it is filled. If it is a bagless unit, move to the next cause.

• Many vacuums will work poorly even after the bag is only about 1/2 full. There's just not enough unobstructed bag area to allow for the necessary airflow. The dirt covers the bag.
• A few vacuums are designed to allow full use of the capacity of the bag, but it doesn't hurt to change the bag.
• If the bag change doesn't improve matters, or the bag is pretty empty, consider if you have recently vacuumed up very fine dust. You can make the bag work poorly because the very fine dust particles will clog it prematurely.
• On some shop-type vacuums, there is a filter that does all the work (kind of like a bag), and when that filter gets clogged with debris the vacuum operates poorly.
• Those filters can be cleaned by knocking the dirt off.

The next thing to check is that the brush roll is spinning.

• What may seem like a lack of suction, can also be caused by the vacuum brushes not spinning.
• If you are using a vacuum that doesn't have rotating brushes or the attachment doesn't have such, skip this section.
• If the brushes are spinning, then move on.
• If they aren't, go through the checks and fixes on our Vacuum Brushes Not Spinning page and then come back here.
• If the brush roll is not spinning on some older uprights, this could be a broken belt, along with a broken fan

The heart of a bagless vacuum is generally some sort of cyclonic device or filter to separate out the dirt particles that are carried by the airflow. These particles then need to drop into a dirt container.

• If it is filled to or above the line on the dirt cup, it will affect suction. Empty it if it is near or above the max fill line. If it is overfull, it can cause the cyclones or filter to clog.
• Empty the dirt cup and check the operation.

Another contributor to poor suction is clogged secondary or internal filters. You may notice that your vacuum is louder because it sounds like it is clogged and is "straining" even after you have emptied the dirt container, or changed the bag.

• This begins the portion of the journey where some disassembly of your vacuum is needed.
• These filters are more commonly found on bagless machines that use a dirt container and cyclonic separation, but bagged units like canister models that have air flowing through the motor will have them as well.
• Some vacuums can have up to three filters, There can be a primary filter, a motor pre-filter, and a motor post-filter.
  • Sometimes the manufacturer may not remind you about one of them, so look carefully, especially for "lifetime" post-filters on the motor.
• The filters are especially important for bagless models.
  • These vacuums don't have a bag so these filters tend to see more particles.
  • These internal filters can become slowly clogged with very fine particles.
  • The filter immediately after the cyclonic portion (the dirt container), will generally clog the worst.
    • It is also most frequently washable but is best pre-cleaned with a vacuum first before washing
    • If you wash it, make sure it has some time to dry (a day is recommended) before reinstalling it.
    • You may find that replacing the washable filter is necessary after several cleanings.
• Some of these filters should just have the dirt knocked off, or better still, vacuumed off of them if you have another small vacuum.
  • You may need to replace, rather than clean that type of filter after a few cleanings.
  • When cleaning this type, you should do it outdoors or at least not over the carpet, as it can be a bit messy if the vacuum has become dirty.
  • The downstream filters are what often gives the vacuum a HEPA (High-Efficiency Particulate Air - filter) capability.
• If you have cleaned the filters, and the vacuum works normally, you are done.
• If no change check for clogs as described below. We check the filters first because lower suction will lead to clogs and a frequent cause of that reduced suction is dirty filters.

Every vacuum needs to move air to operate. Blocked internal passages will prevent that. Just as the filters may require cleaning, so do the air passages of the unit itself.

The same process used on the hose can be used on the air passages on the machine itself.

Likely spots for clogs include:

• Air passages that bring the airflow to the cyclones on bagless canisters can get clogged, check them and remove any debris.
• Many upright vacuums have a short length of hose that allows the handle and body to flex in relation to the base. That short hose can be clogged. You need to disassemble the vacuum to deal with this. Remove any clog you find.
• Check that this hose doesn't have a hole or cracks as well, as they can cause a loss of suction.
• Some upright vacuums have removable brush heads and clogs can form immediately downstream of the brush head. Remove any clogs you find.
• You can use a hanger wire as described above to check these air passages. Push the wire through to remove any debris. Do it a few times, but be careful not to puncture this hose.

Reassemble and test the vacuum. If the suction is normal you are done. It is still a good idea to clean (or replace) the filters mentioned below in any event, as this should be part of the usual maintenance.

• If no clog is found, move on to the next cause.

Models without bags use cyclonic separation, or in the case of shop vacs, direct filtration as mentioned. There are a number of ways that the cyclone can clog.

• The larger cyclone often also has a screen to block large particles from entering, sort of like a coarse filter. It should be cleaned whenever the dirt container is emptied.
• This gets clogged and fine particles can build up on it and cut down the airflow. Make sure to clean it when you empty the dirt cup.
• The smaller cyclones can clog as well and this affects the ability of the vacuum to deal with fine dust.
  • If that dust is carried over, it will clog the motor pre-filter.
  • Such dust can also clog the motor post filter, which is supposed to trap the finest particles

Some older upright vacs use a fan that also has a pulley on it to turn the brush roll through a belt.

• These fans are made out of plastic and are replaceable.
• They are designed to break if the vacuum eats something not digestible (marbles for example).
• If they break you will likely have heard a very loud noise when it happened, and the brush roll might have stopped spinning.
• They can be replaced by undoing the pulley/nut which holds them on and putting a new one on. The suction will be restored.