I've got a GeneralAire model 800 reservoir-style humidifier attached to my furnace--it's on the main trunk of the duct immediately after the air leaves the furnace. There's no humidistat, so it's simply either on or off.

It doesn't seem like it's working, though. The RH in the house is consistently below 30%--the same as it is without the humidifier. There's water in the reservoir and there are four evaporator pads in it. I'm not sure how this is supposed to work other than that the hot air should pull moisture from the pads.

Some random facts: the pads are in the water, but the part of the pads above the waterline is not wet. It's clearly not a plumbing issue, as there's water flowing into the reservoir.

Any ideas? Any help would be greatly appreciated.