My KSTAD70B's compressor keeps running even while a)it's well below the humidity threshold and b)the unit power is off.

SOURCE: LG LD65E humidity variance

Is the compressor running or is it just the fan? If its just the fan it is because it is cycling the air and it uses that air flow to check the humidity in the air. If the fan runs non-stop and the compressor does not turn on or the fan does not shut off there is a problem with this unit and you will need to replace it. Since it is brand new you should still be able to return it to the store.

SOURCE: Unit runs a lot. Doesn't condense much water. Sometimes fan runs alone, sometimes compressor runs alone.

You may also want to check the coils and make sure they do not have dirt or dust on them. If they are clean you may have an issue with the refrigerant level which will cause the coils not to cool properly. For that you will want to contact LG. There could be an issue with the compressor also. LG backs alot of their models with a 5 year warranty. Contact them and let them know about your issue. Make sure you still have your reciept. Here is their contact number:

1 (800) 793-8896

SOURCE: kenmore 580.51650000 dehumidifier: compressor

fan should turn off when compressor not running, the relay switch is stuck open for the fan, and probably needs replacing, but even if it always runs there is no harm and it only uses like 15 watts

SOURCE: right after powering the dehumidifier on, the

Hi,
Here is a tip that will help you with basic trouble shooting..

http://www.fixya.com/support/r3877515-dehumidifier_problems_dehumidifier

heatman101

SOURCE: Unit fan is running but the compressor is not.

Hi,
It could be a bad compressor, circuit board, or maybe even a sensor or dehumidistat...
Here is a tip about dehumidifiers that run but do not extract water from the air..

Dehumidifier is running but no water is in bucket
http://www.fixya.com/support/r4662409-dehumidifier_running_but_no_water_in

heatman101