I have a 3-year-old Whirlpool AD70 model dehumidifier that's supposed to have a de-icer to keep it from icing up. (At least, the manual uses that term). With this model, I have settings for Humidity=Normal and Fan=Auto: it is supposed to shut off when it hits 'normal' humidity.

A few days ago, I noticed that it was never shutting off (which is new) and no water was collecting, so I went to take the filter out, thinking maybe it was dirty, and found that there was a whole block of ice over the coils.

I let it melt, and then did a test today:
- Thermometer in the basement reads 60 degrees F.
- Ran dehumidifier on Normal/Auto setting
- Fan seems to be going, as air is blowing out of the side vents of the machine.
- Left it for an hour, came back, and there's a block of ice around the coils.

While I know it is 3 years old, I thought I'd get at least one more year out of it. It's been a great machine up to this current problem. I'll have to check, but I think there's a 5 year warranty on "sealed" parts. However, I don't know if the de-icer would be considered one of those parts if it is broken.

Is there anything else that you know of that I can try out or test out before calling the 1-800 number?

Ordinarily, dehumidifiers shouldn't be used below 65˚F..

It is model AD70USS0. It has "Control Type 3" according to the manual, and the minimum operating temperature is 38 degrees F. The manual says it has an automatic deicer that will shut off the compressor and allow the fan to run to reduce ice buildup on the coils.

So, sigh. One of the components must have failed. It's been such a workhorse that I hope it's a simple fix.

I just checked the warranty sheet--it says a 5 year limited warranty on the "sealed system", which includes the compressor, evaporator, condensor, etc. So, I guess this means a call to the 1-800 number. :-/