Most vacuum cleaners are designed with a basic function in mind, which is to suction up debris and dirt from carpets and other floor surfaces. While many vacuum cleaners have other features or options that enhance this basic purpose, the general idea is the same -- to clean the floor. If the vacuum cleaner starts to blow dirt back out of the unit instead of suctioning it up, there are various possible reasons why.
Dirt Container or Bag
The most likely reason why a vacuum cleaner is not suctioning up dirt is if the dirt bag or container is too full. Once the bag or container is full, it cannot suction additional dirt up and ends up sending the dirt back out of the vacuum. To resolve this problem, remove the dirt cup and empty it in a waste container or discard the full dirt bag and replace with a new bag.
Hoses and Nozzles
Another possible reason for reduced suction is an airflow problem or obstruction. This can happen when the vacuum suctions up something that is too large or that clogs the hose or nozzles, such as pine needles during the holiday season. To check, disconnect power to the vacuum and remove the hose. Shake it to dislodge any debris and use a long handle, such as that from a broom, to gently push through any objects. Once the hose has been cleared, lower the handle and turn the vacuum over to look at the nozzle. Check for objects that may be causing the problem and clear out the nozzle with a clean cloth. Be sure to fully attach the hose to the vacuum before restoring power.
Many vacuum cleaners now offer a height adjustment option that lets users select the correct type of flooring and change the positioning of the vacuum cleaner accordingly. For example, there are different settings for delicate carpets as opposed to carpets with thick pile and a different setting for bare floors. Owners with vacuum cleaners that have a height adjustment should check to make sure the proper setting is selected, as the wrong setting may cause the vacuum cleaner to malfunction and send dirt back out.
Sometimes the belt on a vacuum cleaner eventually cracks or splits, causing the vacuum to lose suction, which can cause dirt to blow back out of the unit during use. To investigate, disconnect power and lower the cleaner head, then turn the vacuum cleaner over and remove the belt cover on the cleaning head. Look inside the housing at the belt and replace the belt if it seems to be damaged, worn or broken.