Aprilaire 4218 Humidifier Drain Pan;

About the Aprilaire 4218 humidifier water distribution Tray for Aprilaire 550 series the Aprilaire 4218 humidifier water distribution Tray is Replacement part for use with Aprilaire humidifier models 550, 550a amp; 558. The Aprilaire 4218 humidifier water distribution Tray distributes water evenly across the evaporate panel by attaching to the u-shaped scale control insert and incorporating a pumice coating inside.