Dehumidifier freezes up

Most dehumidifiers need warmer air to work properly. The temperature in a basement is usually 60 - 65F; too cool for standard models. You could buy a "basement" dehumidifier. They're designed to work at lower temperatures; some as low as 40 F. Costs are about the same as a standard dehumidifier; you just have to find it.

For a cheap fix, try this; it seems to be working for me.

Since the condensate coil (the one icing up) is cold, the air entering it is too cool and the condensate frosts up the coil. Additional condensate freezes to the frost and before you know it, you've got a block of ice. Since the air coming out of the front is very warm take a large piece of cardboard around 6' x 3') and form a V. Placed it in front of the dehumidifier so it channels some of the warm air back to the rear where it warms the moist air up before it hits the cooling fins. It's helped keep the ice down.

If you want something attractive, any screen that redirects some of the air back to the rear will work. Just leave the top open so it doesn't get too hot and the some of the drier air gets out into the room.