COMPRESSOR DOES NOT TURN ON I HERE THE FAN AND LOW TEMPLIGHT COMES ON. DELONGHI DEHUMIDFIER MODLE NUMBER DH90U

If it is very cold some of these consumer units will not turn on the compressor. If the unit suddenly stopped working and the temperature is room temperature I would guess a refrigeration issue- either a leak or bad compressor. Make sure the "full bucket" indicator light is not on- the condensate bin may not be plugged into the unit properly.

Is the coil cooling? If not it may have leaked the freon out or have a bad compressor. Dehumidfiers work in the same way an air conditioner does to condense moisture out of the air. If the coils don't cool, they will not work.

Hi,
There are many reasons why a dehumidifier willnot work or collect water.
Here is a tip that I wrote to help people to figure out what is going wrongwith their dehumidifier

Dehumidifier is running but no water is in bucket

heatman101

icing is caused by one of two things .. if the air flow is restricted .. or if the unit is low on refrigerant .. the air flow is frequently restricted by dust accumulation in the evaporator coil (where the ice is forming) .. if that the case you can check with a flashlight and wash or vacuum out any accumulation .. . the fan could be running slow due to a lack of lube in its bearings or something might be blocking air flow .. when you first turn it on check for good air flow .. if that is ok then suspect the low refrigerant level ... what happens is that if the correct amount of fluid is in the system then the entire evaporator gets evenly cool but not excessively so .. but if the fluid is a little low then one small section of the evaporator gets very cold .. that freezes and that, in turn, blocks air flow so the freezing process progresses across the entire evaporator until its hopelessly clogged with ice .. you must thaw it out by turning it off for a day or so .. the refrigerant fluid systems in most of these are sealed .. so you don't really have any way of adding more fluid .. a repair person will add a special "saddle valve" that pierces the metal tubing .. that allows recharging the system .. he would also check for leaks .. there is one, or the level would not be low .. sometimes its such a small leak that a charge will last for years and you don't have to worry about it .. the repair person would use a soap/water solution to check for bubbles..or he could use a "sniffer" (a tool that detects leaks) when he finds the leak then he would repair it by braising or epoxy or other patch method .. you would want to get an estimate before repairs because sometimes it cost more to repair than to replace the unit .. thats a shame but thats the way things are now ..

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

flush tubing

Possible low on Refrigerant. Get tech to check it. Rusty

The sealed system of the Kenmore 54701 dehumidifier is warranted (Parts & Labor) by Sears for five (5) years. Since the fan in your unit runs but the compressor doesn't, I suggest that you return it to Sears and request (demand) a new replacement unit under their warranty. I say "demand" because Sears will undoubtedly tell you that the problem is due to some "other" component which is not covered, and will charge you mega-bucks to repair it. Been there - - done that.

FYI, read the (very low) customer reviews of these units on Sears website and you'll see you're not alone in your experience with Sears' inferior quality units.

Above all, do NOT pay to have it repaired. That money is better spent on the purchase of a far more reliable brand of dehumidifier - - (which will most likely cost less that what you paid for the Sears unit).

I went back and rechecked. If the fan mode is selected, you can only set the fan at one of the three speeds. If you leave it in the fan mode, the dehumidifier will not come on.

Once the fan speed is selected, it will run at that speed in the dehumidifier mode. The fan will keep running, even when the dehumidifier (compressor) shuts down.

The only way to get it to turn off is to use the clock setting, which either selects how long it stands-by before starting , or how long it will run before going back to stand-by. DeLonghi calls it "stand-by," we would call it "off." DeLonghi calls unplugged "off."

I've never turned mine to stand-by, because it will never get my entire house down to 30% humidity (I have it where my air handler returns air to the basement). I live in the greater DC Metro area, where 75% humidity is considered extremely dry.

Apparently the normal mode of operation is fan on unless awaiting a clock start, or encountering a clock shut-down; either condition puts it into the "stand-by" mode.

Calling two service centers, they both indicated that the main circuit board needed replacing. This would need shipping the unit!!, part and then labor. I figured over $120 - not reasonable. I then took the unit apart and followed the wires from the compressor to the back of the unit. This is where the moisture sensor was located - upper left. You'll see this when you take the filter off. Anyway, I cleaned the face of this part with a old toothbrush, used some compressed air to remove any dust. I then followed the wires with the black sleeve that went to what I think is a temperature sensor - also on the left. The wires go to a sensor that is pushed into a copper tube that is part of the cooling tubing. Gently pull this out, wipe it down and re-install. I then plugged the unit in, set the humidity level and it now works. I just put the unit back together and the compressor is turning on and collecting moisture! I will run it a few days and keep checking on it to make sure it doesn't go into the 'E3' Mode. By the way, the repair shops I called really didn't have a clue what the E3 code was. Dennis