Used on a Bissell vacuum - there is an airflow sensor and if the filter is clogged enough to restrict airflow the vacuum will just shut off ( no longer works) . First, remove and replace that sponge pre-filter that sits on top of the pleated filter. But I have found that with a little effort you can salvage a dirty filter with good results. Wash the sponge filter in warm water and let it dry completely. Above the sink - "tap" the pleated filter lightly to shake off the dirt. I use a butter knife and scrape the inside of each fold to remove dirt. When this is done it will look cleaner and can be put back in place with the sponge filter and the vacuum will work just fine. They last a long time - months or even a year. When the vacuum turns itself off - there seems to be a timer and it doesn't start up again right away - it can take a few minutes for it to start up again, even with a new set of filters. I've been doing this for a few years now and it should work with any HEPA or pleated filter setup. I also do this with the pleated air filters on my tractor by blowing them backwards with a compressor (use respirators - dust is bad).