Not sure what you are asking. IF you mean that the coils within the unit, probably in the back area have frozen over with some icing: Then the unit is probably low on freon. Freon you ask? Yes, a dehumidifier is nothing but a small air conditioner which pulls/pushes room ambient air across the cold coils causing the dew point of the ambient air to drop and the water condense on the coils. This water will drain off the coil tubing and into the waste water bucket to be emptied. Can you service these units--Sorry No. These little units are sealed up tight vs. a home air conditioning unit. Freon cannot be added by a homeowner/DIY person unless they have special tools and knowledge of how to do these. They only carry like 2 or 2.4 ounces of freon also. Very hard to put this tiny amount in a system.
Also check/clean the filter and check for any air obstructions, or if the fan is dying. The air passing over will more or less warm up the coils enough so they don't freeze, but like an AC unit, if there's not enough air, it will freeze.
If it is indeed low on freon, there is probably a leak. You could maybe get an hvac person to look at it, but unless it will only cost like 30 bucks or it's a big expensive unit, probably not worth paying too much in repairs. If you dispose of it, treat it like a fridge or AC unit, you can't just bring it to the dump.
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