Aprilaire 4231 Replacement Yellow Orifice for Aprilaire Humidifiers

Aprilaire 4231 yellow orifices are the tiny nylon components which accurately meter the flow of water into your humidifier. This allows for homeowners or technicians to quickly adjust the rate of water flow to the humidifier. Make sure the correct orifice replacement part is unique to your model of Aprilaire humidifier.

Used in the following Aprilaire Humidifiers:

Model 400

Model 400A

Model 400M

Model 500

Model 500A

Model 500M

Model 550

Model 550A

Model 558

Model 560

Model 560A

Model 568

Model 600

Model 600A

Model 600M