How To Maintain And Replace A Bypass Furnace Humidifier

The humidifier is one of the most important parts of your home heating system. By moistening the air, it prevents problems like dry, itchy skin and respiratory inflammation. However, if you do not properly maintain your humidifier it can do more harm than good as bacteria builds up inside the drum. While there are several different types of furnace humidifiers, bypass humidifiers are the most common. Here are some tips to help you maintain and replace a drum-style bypass furnace humidifier.

Refill the Humidifier Daily

Most people know that stagnant water is one of the easiest environments for bacteria and mold spores to build up in. To prevent these contaminants from polluting the air that your furnace blows into your home, you should replace the water in your humidifier at least once per day. After you have emptied the humidifier, you should wipe down the inside of the reservoir. Use a natural cleaner if possible, as chemical cleaners can sometimes contaminate your air with harsh odors that cause respiratory irritation.

When you are refilling your humidifier, you should use distilled water instead of tap water if possible. The minerals that are naturally found in tap water can release a byproduct known as white dust into the air. While white dust is not thought to be harmful, it can settle on the furniture and floor around the registers in your home, causing them to look dingy and dusty.

Check the Foam Pad Every One to Two Weeks

Inside your humidifier, there is a rotating drum wrapped in an absorbent foam pad. The pad dips into the water in the reservoir as the drum turns. The air from your furnace picks up moisture from the pad as it passes through the humidifier and disperses the moisture throughout your home. The pad should be cleaned every one to two weeks to keep bacteria and mold spores out of the air.

To clean the pad in your humidifier, turn off the power to your furnace and the humidifier and open the outer cover of the humidifier by removing the clips or screws that hold it in place. The pad will also be attached to the drum with a clip. As long as the pad is soft, you can rinse it with white vinegar and water, wring it out, and clip it back in place. If the pad has hardened, you will need to replace it with a new one.

Replace the Humidifier as Needed

In some situations, cleaning your humidifier will not be enough, and you will have no other option than to replace it. The most common problem that requires you to replace the humidifier is when the drum stops rotating because the drum motor has burnt out. You may also need to replace the humidifier if the water valve has become too clogged with mineral deposits, mold, and corrosion.

To replace the humidifier, you will need to turn off the power to the furnace and humidifier as well as the water valve to the humidifier. Remove the water line and bypass duct from the humidifier, and disconnect the wiring to the humidistat and solenoid valve.

In many cases, you will not be able to find the same model of humidifier that you had previously, especially if the unit is 20 years old or more. When you install a newer model, you can benefit from new features like automatic outdoor temperature compensation, but you may have to make an adapter plate to fit the new humidifier into the old slot. To do this, first place a new piece of sheet metal over the opening and secure it with sheet metal screws. You will then trace the size of the opening needed for the new humidifier, and cut out along the lines with a pair of tin snips. Fit the new humidifier into the cutout, and reconnect the wiring, bypass duct, and water valve.

Humidifiers are not complicated devices to maintain or replace, and doing so will greatly increase the air quality in your home. Keep these tips in mind, and if you need help with any of these steps or other HVAC system problems, you can check out the sites of local HVAC companies or contact them in person. 


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