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Bottom-Emptying Unit Maintenance

How to remove, swap, and clean the bottom canister of your central vacuum system.


There are different filtration methods used in a central vacuum, depending on the construction of the unit. Bottom-emptying units have an inverted filtration system which provides longer lasting power. For maintenance purposes, we will be covering how you can clean out your bottom-emptying power unit. When checking and changing your bag, it is also important to check that the filter is cleaned and clear of debris. If the filter is blocked, it prevents air flow and increases wear and tear on your motor and fan, decreasing its longevity.

Central Vacuum maintenance is crucial to a high performing unit. One of the most important tasks is checking the bag or canister and timely swapping it out for a new one, or emptying its contents. One great feature about our bottom-emptying units is the large capacity for dust, dirt, and debris which means a bag swap is a less frequent task; the Airmaster® has 5 gallons capacity and the Airmaster XL has 8 gallons capacity. Depending on the household and usage rate, your bag may not need to be changed for 8-10 months! Here is how to check and replace the bag from a bottom-emptying power unit.

How to Remove the Central Vacuum Canister to Access the Bag

Important: before you begin, ensure that your unit is unplugged.

  1. Unclip the latches on the side of the unit one at a time.

    Unclip central vacuum canister
  2. If necessary, slightly twist the bucket to further loosen it, and then pull the bucket down to separate it from the unit.

    Remove central vacuum canister

Paper Bag (Remove, Clean Out, and Replace)

Important: before you begin, ensure that your unit is unplugged.

  1. If no bag is being used in your central vacuum unit, empty the debris from the unit with a plastic bag and wipe down any remaining dust or dirt. Be sure to wear a mask as debris can get in the air during this process

  2. If a disposable bag is used, follow the steps above to remove the bucket.

    Seal central vacuum bag

    Then, slide the cardboard/plastic pieces of the disposable bags off the pipe fitting they are connected to and seal the bag. You can now dispose of the bag.

  3. Get a new bag, and slide the cardboard/plastic pieces over the pipe fittings, and make sure the connection is secure so it does not slide off when the vacuum is running.

    Attach central vacuum bag
  4. Lift the bucket back up to the unit, re-fasten one latch at a time, and then make sure there is a good seal.

  5. Plug your unit back in and power it on to double check that the bag was properly attached to the unit.

Cloth Bag (Remove, Clean Out, and Replace)

Important: before you begin, ensure that your unit is unplugged.

The replacement or reattachment of cloth bags are quite different compared to swapping out a paper bag. Here is a quick breakdown to show you how to reinstall your cloth bag into your bottom-emptying central vacuum unit.

  1. After you have removed the central vacuum canister, it's important to locate the cloth tab. If you cannot locate the cloth tab, you can use a flat head screwdriver to wedge between the metal ring sewn into the bag and the Central vacuum unit canister to allow you to compress it to the center and pull the bag straight out.

    locate tab
  2. Then, you can shake out the bag to remove any debris that is in the fibers or hand wash the bag. Ensure that the bag is entirely dry prior to reinserting.

    remove bag
  3. To reinstall the cloth bag, you must compress the metal ring that is sewn onto the bag to the center and insert it into the groove of the unit above the intake ports. The bag should stay in the groove of the unit which will prevent it from being suctioned up into the system when in use.

    insert bag
  4. Plug your unit back in to ensure that the bag is indeed secure.

Legal Disclaimer: Any action taken upon the information on this website is strictly at your own risk and MD Manufacturing will not be liable for any losses or damages in connection with the use of our website. MD Manufacturing, in any way whatsoever, is not responsible for your use of the information contained in or linked from these web pages.

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