I have never had so much trouble with an media air cleaner as I did a few weeks ago. I have been laboring at a cooling and heating contractor for numerous years as the a/c, furnace, and media air cleaner service woman The cooling and heating contractor I work for sells all kinds of air filters, a/cs, media air cleaners, and furnaces. I work in a shop where Heating, Ventilation, and A/C shoppers can bring their broken or messed up a/c units, UV light media air cleaners, warm water boilers, and other Heating, Ventilation, and A/C units to be fixed. One afternoon, an elderly lady brought in her small HEPA air filter for a repair. I asked what was going wrong with her HEPA air filters, and she said she had no idea; Some days the air filter would work fine, other days it would start making loud noises and get really hot. I took the air filter apart thinking I would be able to repair the problem relatively rapidly. I thought that it was just the air filter that needed to be fixed or maybe the air ducts cleaned, however after doing all I knew to do and putting the HEPA air filter back together, I was surprised that the unit was still having the same problem. After taking the air filter apart again and inspecting it, I was at a loss of what to do next. I went and got some bizarre heating and cooling device for sale and did some bizarre stuff to the air filter, however to no avail! Finally, I found the problem. A tooth to the lady’s denchers had fallen into the fan of the media air cleaner and was causing it to malfunction.