How to fix and maintain dehumidifiers

Caution: Before cleaning or repairing, unplug the appliance, let the motor stop, and allow hot components to cool off.

A dehumidifier’s fan draws air from the room and pulls it over the chilled coils of its evaporator. The resulting moisture drops into the drip bucket. The dry air then passes over the condenser, regaining some warmth.

Clean the unit every 6 months of use. Unscrew the front and rear panels; vacuum the inside with a crevice cleaning attachment, concentrating on the fan and coils. Scrub mineral deposits from the coils with a stiff brush. Tighten screws and nuts. Water overflow

The drip bucket may overflow because of a faulty overflow-prevention switch. Disconnect the switch and test it with a continuity tester. If the tester lights when you press the switch’s push button, get a new switch, If the drain trough under the coils overflows, look for and remove any obstruction in the drain hole. Short-cycling

Quick on-offs are usually caused by icing, the result of dirt clogging the condenser fins. Clean the coils as described above. Run an old comb between bent fins to straighten them. Noisy operation

If a fan rattles, it may be loose on its motor shaft. Turn the blades by hand; if the fan wobbles, tighten the set screws on its hub; if there are none, replace the rubber hub that connects it to the shaft.

If you suspect there’s a worn bearing in the fan’s motor, dismount the fan from the unit by unscrewing the two mounting nuts. Unscrew the fan from the motor shaft. If you can move the shaft up and down or left to right, a bearing is worn. Get a new motor.

If the unit doesn’t operate in a working receptacle, unplug it and check the cord. Next, disconnect one lead to the humidistat. Test the humidistat with a continuity tester while you rotate the control knob. If the tester doesn’t light, replace the humidistat.