The dirt, hair or whatever that was picked up isn't swirling in the tunnel. Everything is sticking in the filter. Is there a loss of suction somewhere? It didn't always do that.

Perhaps dirt or hair is stuck or the full canister needs to be emptied, remove blockage and suction should return.

You obviously have a pet and it's good to see your machine is doing it's job. The only reason you could lose suction while collecting pet hair is due to the pet hair being a solid mass and air not been able to flow through the filters.( must be a lot of hair). Suction loss is only when the particles passing through your machine are dense therefore it will reduce suction and airflow . Very common on vacuum cleaners. Do not worry too much . Also check to see if you have Amy cracks in the seal between the drum and the vacuum cleaner itself

Could be a clog of course. Id run a coathanger or something similar through the tunnel the dirt goes up through.

Another thing is if the dirt cup and filter aren't seated right, it could stop suction.

You could take the dirt cup off, and turn the machine on, and see if there is any suction right at the motor, carefully of course. That could rule out a fan/motor issue.

The belt and brush have nothing to do with the suction. The impeller on the motor creates negative pressure which results in a vacuum. ( or suction ) Many newer vacuums have as many as 4 filters. if any become completely clogged, the performance drops to nil. Start at the debris exit and work backwards. As a bagless, pulling the dirt canister out and removing the main filter is a good start. Most filters can be "tapped" clean and some are washable. after pulling out the filter, look where the passage way enters the filter chamber. Is it clogged? There is usually a secondary filter, which actually is set in a previous stage to the filter you just pulled out. Its main purpose if to catch hair, small nails, wire, and other material that could damage the more visible filter. If this filter is clogged then that will explain the loss of suction. Pull it out and clean it. An exhaust filter is located typically above the motor. Its purpose is to prevent fine particles from being blown about. It should be cleaned as well. With the filters clean and the hoses and passage ways clear, you should be good to go.
Good Luck!

I found out that if you remove the front filter holder, tip vacuum back and look down inside. Sometimes there is hair caught back in there and you won't get suction. I had to use something long, knife, very long type tweezers, to pull all the hair out. Worked great after that. About half way through vacuuming I will stop and remove the foam rubber filter and clean it. Oh yea, you will have to use a flashlight to look down inside to see all the hair caught behind the foam rubber filter cup.

Did you clean out the short hose that connects the powerhead to the body?
One big problem with many uprights is that the fan/s that create the suction are installed in such a way as all the dirt, sand, and whatever go through it before reaching the bag. This can cause extensive damage to the blades, causing loss of suction. Solution: replace fan.
It sounds like there's a clog somewhere, though. You'll need to check any area between the power nozzle and the bag/dirt holder for clogs.

Hi there it's SmartAlec from NelsonVacuums.com.au here. 9 times out of 10 the loss of suction on this machine will be due to worn or blocked filters. It is most likely to be the filter which is in the dirt canister. It is a bit of a pain to clean but it is the best way to restore lost suction. Simply remove the filter and tap it out and then start brushing the dirt from all the little grooves using a paint brush (dry of course) or similar. If you are lucky enough to have an air compressor this is by far the most effective but be aware it will make a mess so dont do it in the lounge room. If you think this is not the problem send me another message and ill see what else i can suggest. Happy Vacuuming :)

that is normal for the vacume to shut off if the motor overheats you must keep teh dirt cup clean and empty and all the filters clean, when you empty the dirt cup if you have a lot of pet hair take the hose off and make sure that it is clean as well, and do not try to pick up any of those cleaning wipes that will stop it up real quick

You have an airflow problem. You may still have a blocked intake or tube, also check the filter. The air is supposed to go in the bottom (of course) and I'm sure you k**w where it goes out. You probably can **te a reduction in exhaust. If this is a bagless make sure everything is fitting together properly. Mis-aligned components on a bagless can mean little or ** airflow. If this is **t a bagless, try changing the bag whether it is full or **t.

Move the lever on the front of the machine to "carpet". It won't agitate on floor