I've been meaning to post this for some time (forgive my laziness). I did a search of this site to ensure I wasn't about to beat a dead horse and was surprised to see not one thread addressing this issue. Since my earlier days of working for a company that does alot of new residential construction I have made it my mission in life to make customers aware of the importance of keeping their humidifiers cleaned and that if they can't they should get rid of their drum type humidifier and replace it with a drip style such as a Aprilaire 550.
What prompted me to, finally, start this thread was, just recently, I had a no a.c. service call on a system that had a drum type humidifier mounted on the return of a furnace and before I even looked at it I mentioned to the customer how she should get rid of it. When I did look at it it only reaffirmed my commitment to inform the public of how disgusting these things are. The muck was so thick in the pan you could see how the drum was dragging thru it. The customer gagged when I showed it to her and she told me to take the thing out the system which I was more than glad to do even though I hate having to handle these things.
It makes me wonder why these things have not been outlawed. Time and time, again, I find this type of humidifier full of what looks like pond scum. You have to wonder what type of mold spores and other potential diseases these things are subjecting the customers to. I know from what I read on this site that most of you are professionals. If you sell this type of humidifier and doubt what I say I dare you to go back to several of earlier installs and see, firsthand, what I am talking about. You may say that it is the customer's responsibility to keep up with the proper maintenance of their equipment, but as anyone knows who has worked in this field for any length of time most customers don't want to be bothered with the very regular required cleaning of these things. This is, also, why I don't sell electronic air cleaners. They are a pain in the ass to clean and customers couldn't be bothered and both items are only good to have if they are regularly cleaned. And to the customer's defense I have been told by them many times that no one bothered to explain to them what was required to properly maintain their system. (Maybe, if someone had, beforehand, they would never have opted to buy these things.)
Sorry to be long in the tooth, but I felt it too important to allow this matter to go ignored any longer.