The Aprilaire 4231 Humidifier Orifice is a tiny red nylon component that allows a specific amount of water to enter your humidifier. It's designed to regulate the amount of water entering the humidifier from the solenoid valve. Some of the water will evaporate and some performs the important flushing action. This process will keep the water panel clean while reducing maintenance to a minimum. Also known as part number 4231, the Aprilaire humidifier orifice is a unique fit for several Aprilaire humidifier models.
The Aprilaire orifice could become clogged with mineral deposits and sediments, such as rust and scale. For optimum performance of your Aprilaire Humidifier, replace your orifice annually, based on usage and water quality.
Aprilaire: 400, 500, 560, 560A, 568, 550, 550A, 558, 600
Recommended Replacement: Annually
Disconnect the power and shut off your water supply before servicing. 120 volts could cause serious injury from electrical shock. Don't forget to clean or replace your inline strainer when you replace your orifice.
Other Stock Numbers: UAPRILAIRE4231O