For those rare occurances where an automatic control is not practical, Aprilaire offers a manual control to meet your needs. The Aprilaire Model 500M is the economy version of the 600M intended for use in smaller homes. It takes humidifier innovation to the next level and performs as good as it looks! The Aprilaire 500M is easier than ever to install because it includes a built-in bypass damper, which means fewer parts to install. Plus, the damper is conveniently labeled for summer and winter settings, allowing you to set it for the entire season with no guesswork involved. This humidifier can be installed on the supply or return air ductwork. It is also left or right side reversible. Includes manual control humidistat, water pad, 110v to 24v transformer, and manufacturer’s special instructional DVD.
Other items needed for the installation that are not included: 1/4″ copper tubing for water line, 1/2″ ID plastic tubing for drain, 6″ round ducting & elbow for bypass air, 2-conductor 18 to 22 gauge wire.