How to Maintain and Fix Your Dehumidifier

By Gary Hedstrom, Peg Hedstrom, and Judy Ondrla Tremore from How to Fix Everything For Dummies

For the most part, dehumidifiers are trouble free, but they do require maintenance — emptying the tank, cleaning it periodically to keep bacteria and mildew in check, vacuuming the dirt from the coils, and replacing the power cord and plug if they get worn.

In the summer, excessive humidity saps our energy, robs us of sleep, causes health and safety problems — especially in the elderly — and makes basements smell damp and musty. So if you don't have air conditioning to help dry out your home, the next best thing to do is to buy a dehumidifier. They also come in handy in the spring or fall when there's a lot of rain but the outside temperature doesn't justify air conditioning. Equipped with an evaporator coil, compressor, fan, and humidistat, dehumidifiers wring moisture from the air. A comfortable moisture level during the summer is 35 to 40 percent.

If it gets cool outdoors and you keep the dehumidifier in the basement, the coils will freeze up if the dehumidifier is switched on. Fortunately, all you have to do is turn it off manually and when you need it again, turn it back on.

When humidity is high, a portable dehumidifier with a 4-gallon tank needs to be emptied at least once a day. After the tank is full, the dehumidifier switches off and doesn't start working again until you empty it.

You can tell when a dehumidifier needs to be fixed — when the weather is hot and muggy, but there's not much water in the tank. Here's how:

Clean and vacuum the coils.

Dirty coils also cause freezes. So whenever they accumulate a lot of dust, clean them.
Tighten the screw on the fan shaft.

It may have slipped.
Replace the fan motor if it's barely turning (low revolutions per minute).
Take it to a service technician if Steps 1 through 3 don't fix it.

The compressor may not be working or the dehumidifier may need recharging.

If you notice one or more fan blades are bent, they will have to be replaced before they damage the motor. Buy new ones, getting the manufacturer's name and the model number off the unit or from your owner's manual. Then head to the nearest appliance parts store. When the fan blades need to be replaced, here's what to do:

Take the front panel off to get at the motor.
Take the motor out, if necessary, to get at the fan blade.
Loosen the set screw in the blade hub and pull the blade off.
Slide the new blade hub on and tighten the set screw.

When installing new blades, be sure to tighten them on the shaft exactly where the old one was so they don't hit the fins or the motor.
Put everything back together in reverse order.

Sometimes a dehumidifier won't run because the humidistat is faulty. Here's how to replace it:

Unplug it from the wall.
Pull off the knob.
Take off the nut holding the switch in.
Disconnect the wires.
Take the humidistat to an appliance parts store along with the numbers off the data plate to find the right replacement.
Install the new humidistat by following the first four steps in reverse order.