The unit makes a loud rumbling sound and smells hot. serial # is QU so its not one Whirlpool is recalling. I turn off and unplug unit wait a minute or so plug back in and turn on and works fine. Time passes and processes starts again. This happens throughout the day.

Clean the coils

Some dehumidifiers with the model number, FAD504DUD, are subject to a recall. Record the serial number and then go to https://www.recallrtr.com/dehumidifier to check if your unit was manufactured in the bad batch.

Without the serial number, I can't be sure if your unit is in the 2016 recall. For details, you can look at https://www.cpsc.gov/Recalls/2017/Dehumidifiers-Made-by-Midea-Recalled .

I hope this helps.

Cindy Wells

no
not from fixya site as we do not have any paper work for anything
get it from manufacturer web site on google

Mary,
There is a recall on Whirlpool dehumidifiers that may cover your unit, the website lists serial numbers of units on the recall list.
Dehumidifier Recall FAQs
I assume from your question that at least the fan is running. There are many reasons why a dehumidifier is not removing water from the air. Most likely is accumulation of dust and pet hair that restricts the air flow. If you can, unplug it, take off the covers and vacuum out all the dirt from the evaporator and condenser (little radiator like parts). This website has some good blow up pictures of how it is put together and part nomenclature:
WHIRLPOOL DEHUMIDIFIER Parts Model AD25J3 SearsPartsDirect
If the air flow is restricted, the compressor has to work harder to the point that the overload gets tripped. It may or may not be resettable; it is part #10 in the diagram on this page:
http www searspartsdirect com Whirlpool Dehumidifier Parts Model AD25J3...
If you do take the covers off, check that the fan turns freely and you may want to add a drop of oil to each end of the motor if there is a place to oil it. Light oil like sewing machine oil or light engine oil will do.
You cannot really tell if the compressor is working with all of the covers on; and I cannot recommend plugging it in with covers removed because there may be open electrical connections that you do not want to touch. However if the compressor is running, the outlet tube will get hot; that is the one that goes to the condenser [radiator like bundle of tubes nearest the fan] [it may get too hot to touch]. The evaporator [bundle of tubes farthest from the fan] should start to get cold where the tiny little tube from the condenser joins. If neither is happening and you are sure the compressor is running, it is out of refrigerant [freon] and may or may not be worth fixing. If the evaporator ices up [gets covered with frost] it may be low on refrigerant indicating a leak; again it may not be worth fixing.

Your description indicates a loss of refrigerant in the dehumidifier. The metal heat exchanger above the water collector should become cold when the compressor is running - if it does not, your dehumidifier likely has lost it's refrigerant charge. You will have to take it to a certified (refrigerant handling) technician to repair. It may make more sense to replace with a new dehumidifier.

Check the CPSC website for dehumidifier recalls. they will have details of the brands/models/serial numbers of recalled units.

Your description indicates a loss of refrigerant in the dehumidifier. The metal heat exchanger above the water collector should become cold when the compressor is running - if it does not, your dehumidifier likely has lost it's refrigerant charge. You will have to take it to a certified (refrigerant handling) technician to repair. It may make more sense to replace with a new dehumidifier.

Check the CPSC website for dehumidifier recalls. they will have details of the brands/models/serial numbers of recalled units.

Have same issue with 3 year old Frigidaire dehumidifier purchased in 2012. Must unplug to stop compressor running with power switch turned off. Unit gets hot and smells. Unplugging creates arcs at outlet since unit is pulling a lot of power. Plugging back in after some hours will make it appear to run normally and again remove moisture but it will not shut off when the fan goes off (humidistat bad?) and the set-point is reached. Cannot leave plugged in due to safetty/fire/overheating concern. Have not found answer on this forum or any other so far.

To figure out what Code F2 is, I took a look at the Owners Manual for the Model # AD70USS, Strangely, the Owners Manual doesn't list an F2 Code or any codes for that matter. Because that model number humidifier, does not have an LED screen.

Never the less, to reset your unit using an alternate method. Turn the Master ON/OFF Switch to OFF and unplug the unit from the wall outlet. Wait 12 - 15 minutes before plugging it back in. Then turn the Master ON/OFF Switch to ON and the dehumidifier should have reset itself. If it doesn't check the positioning of the water bucket, to make sure it's contacting the safety switch. Eventhough, you're using a drain home, it's still important.

Hope this helps you solve the problem.

Hello,

First, make sure the humidistat isn't set too high by adjusting it to the lowest humidity setting and running it again. Next, test the dehumidifier by placing it in a closed bathroom with a hot shower running. If you don't see water collecting in the unit after several minutes, turn the unit off and clean all dehumidifier filters and coils. If, after adjusting the settings and cleaning the unit, you still don't see water collecting, you may have a refrigeration issue. This situation will have to be addressed by a qualified technician.

Take care.

sounds like a sealed system issue it has a 5 yr. warrenty on the sealed system, cost to repair might mean an new one instead