How to Clean a Dehumidifier

By Donald Grummett

The de-humidifier is a niche product. Its only job is to remove moisture from air to alleviate the problems of mould and mildew. It is very similar in operation to a window air conditioner.

A dehumidifier though will add heat to the room, while an air conditioner will remove heat.

The de-humidifier is an appliance that requires regular maintenance. This may be because it’s icing up, overflowing, not removing enough moisture, or simply time for a good cleaning to maintain its efficiency. If you don’t feel handy enough to attempt this project contact your appliance repair person.

The following is a step-by-step method used to return your de-humidifiers to its peak efficiency.

Tools required:

1 Multi pocket container (old ice cube tray)
2 Long handled brush
3 Oil can
4 Rags
5 De-greaser or spray detergent
6 Selection of screwdrivers
7 New filter

Lets get started...

Remove water collection bucket and put aside.

Remove the filter from rear of machine. Filer is usually within a frame and simply pops out. If no filter proceed to next step. If it is a disposable filter simply replace it with a new one. Other types are made in a plastic frame and can be cleaned and reused.

To clean a filter lay it flat in the sink and sprinkle surface with powder laundry detergent. Plug sink drain and turn on hot water. Cover filter with enough water to submerge. Soak for 15 minutes. Remove from water and rinse. Hang up to dry while proceeding to next step.

Remove the rear grille from the main body of de-humidifier. If none proceed to next step. If there is resistance then look for hidden screws. If grille locks into cover proceed to next step. Once removed place the grille aside until later.
TECHNICIANS HINT: Dehumidifier may use different types and sizes of screws. Use ice cube tray to segregate.

Remove metal cover of de-humidifier to access inner workings. Cover screws may be difficult to see because are often painted to match body color. Usually two or three screws along each side of base.

Once screws are removed lift the cover straight up. Use extreme caution at this point. Front grille may be secured to cover. Some fronts are put together like a puzzle. Parts often interconnect or are screwed to one another. If front grille lifts off with cover try to separate before proceeding. Front grille may lock into groove along front edge of cover. Avoid pulling off any wires from humidistat or indicator light.

When cover removed this will expose the heating and cooling coil. They may appear as one but are actually two separate coils in very close proximity. Both will need to be cleaned.Use a narrow brush to remove surface dust and dirt from the front and rear surfaces of coils. Use an up and down motion to avoid bending fins. Area between two coils must also be cleaned. Use caution, the fins are soft aluminum and can be easily damaged.Once surface dirt is removed, spray with de-greaser or light cleaner. There is a good product on the market called HVAC cleaner. As the name implies it is meant for Heating, Ventilation, and Air Conditioner coil cleaning. If this is not available Fantastic Spray cleaner used in kitchens and bathrooms works quite well.Remove dirt and excess cleaner by slowly pouring warm water into fins. Do not allow the water to enter any electrical connections or components. As an added precaution cover the motor with one of the cloth rags to protect it from the water.

With cover, rear grille, and front grilles removed locate fan motor oil holes. Add a few drops of oil to each end of the motor body. Use a general purpose (3in1) oil or clean motor oil. A #30 oil is sufficient. Three or four drops on both ends of the motor body are sufficient. Add the oil slowly, pausing a few seconds between each drop. If added too quickly over-lubrication will result.

Straighten any bent fins. Use a fin comb if available. If no fin comb then use something soft such as a Popsicle stick. Straightening the fins will increase the efficiency of the airflow through the coils. Use caution as these coils are filled with high-pressure refrigerant.

Wipe any dirt from fan blade using a soft rag. Do not bend blades. This would cause a vibration that would harm the motor.

Vacuum all surfaces including front and back of grille assembly. Vacuum underside of metal cover. Vacuum dirt buildup from base and any other exposed surfaces.

Drain any water left in the base and allow it to dry.

When completely dry plug in and test operation. On some models testing may require temporary override of bucket overflow switch. Test that cooling coil begins to sweat water within few minutes of operation. If everything appears okay unplug and reassemble. Insert water collection bucket slowly to avoid damaging float switch mechanism. A bend float arm can allow water bucket to overflow, or affect compressor startup.

Repeat this simple step-by-step procedure every year. If you do, the machine will be ready for many more years of dependable service.

TECHNICIANS HINT: Invest in an appliance condenser brush to clean the coils. Can be used to clean a multitude of household items including, refrigerator, air conditioner, de-humidifier, vacuum cleaner, and electric dryer. A great multi-function tool for a do-it-yourself person. Approximately $10 at any appliance parts store.

Copyright 2007 by Donald Grummett. All right reserved. Donald Grummett has been in the trade over 30 years as a technician, business owner, and technical trainer. Visit MG Services to learn more invaluable information about your appliances.

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Last Modified: 24 March 2020