Honeywell F58F Owner's Manual - Page 8

If you have a humidifier If your system includes an atomizing humidifier, you may want to install a standard furnace filter between the humidifier and the air cleaner. This filter would keep the humidifier spray's mineral deposits from collecting on the air cleaner. This filter should be checked regularly and changed when it shows signs of mineral or dirt buildup. If you do not install a filter, you will probably need to wash the cells and prefilters more often to remove the mineral buildup. If an ultrasonic room humidifier is used often, especially if filled with tap (undistilled) water, the cells and prefilters will require more frequent washing. A white residue will accumulate on the cells from the minerals in the water. This residue may also contribute to "white dust" (see p. 17). All Honeywell whole house humidifiers may be used in a system with the Honeywell Electronic Air Cleaner without any additional filters or system modification. 69-0764-2 6