You must maintain your furnace humidifier at least once per year or the resulting water leakage will damage your furnace and other property!
Most furnace humidifiers work by flowing water over a water panel/evaporator pad. This pad is located inside the humidifier. Overtime, the pad deteriorates and must be replaced. Humidifiers are not 100% efficient which means some water is not turned into water vapor which humidifies your home. This excess water exits the bottom of the humidifier into a drain hose. This end of the drain hose is connected to a typical floor drain. Because the evaporator pad deteriorates over time, material flows with the excess water into the drain hose. This drain hose can become plugged with debris and if not cleaned may cause damage to your furnace and/or household items near the furnace.
As a result, you should check the drain hose periodically through the season to make sure there are no plugs. If there are plugs you should clear the hose. Also, furnace humidifier pads should be changed one or two times a year, depending on how hard the water is. We do not recommend cleaning the humidifier pad; it is NOT a good idea to use lime away or similar products to clean the pads. It IS a good idea to purchase the manufacture pads, not store bought knock-off or generic pads. If you do purchase store bought pads then you should replace them more often, at least two to three times a year.
In addition, if you have a humidifier with a reservoir that holds water (many older-style Sears brand units), the rotation media needs to be cleaned every three weeks to prevent buildup of harmful minerals and bacteria.
For Carrier, Aprilaire, General or Auto-Flo humidifiers, you must replace the evaporator pad at least once each year. For hard water areas the pad must be replaced twice each heating season. The Carrier model has a separate distribution tray that must be changed along with the pad. If you have a humidifier with a reservoir that holds water, the rotation media needs to be cleaned every three weeks to prevent buildup of harmful minerals and bacteria.
Most of our customers leave the maintenance of the humidifier up to us to do every season. We typically do the humidifier maintenance when we do the furnace maintenance. We have pads and parts for Carrier, General, Aprilaire and other brands. When we do the humidifier maintenance we do the following: