The Aprilaire 4594 is the correct replacement for the following humidifiers:
The Aprilaire 4594 Duct Mounted Humidistat is for use in your Aprilaire 1150,1160,and 800 model whole-house humidifier system.These steam humidifiers are self contained systems and the humidifier humidistat measures and controls the relative humidity in your home.
The Aprilaire 4594 Specifications:
The Aprilaire Whole house humidifier humidistat is a key component to keeping your whole house system working at its best. This humidifier humidistat is mounted to your duct, as these steam humidifier systems use a distribution tube ithrough your duct work to provide humidified air. To keep your whole house system working at its best, use the Aprilaire 4594 Duct Mounted Humidistat.