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  • Genuine Aprilaire humidifier replacement part
  • Ensures that the right amount of humidity is delivered into your home.
  • Controls how much moisture enters your humidifier, making it possible to maintain proper humidity levels throughout your home.
  • Compatible with Aprilaire humidifiers models 400, 500, 600 and 700.
The Aprilaire 4040 24-Volt solenoid valve allows water to come into your humidifier. Other parts that may be needed with this part are the, #4004 and the orifice, part number 4231, 4232, 4007 and 4021 depending on which Model humidifier that you have.

Both the inlet and outlet are threaded 7/16" - 24 UNS for accepting a compression fitting for 1/4" tubing. The inlet includes the compression fitting & ferrule. For the outlet, your existing compression fitting is reused.

Proper humidification of your home is important for protecting your family’s health and the beauty of your home. The 4040 24 Volt Solenoid Valve controls the amount of water that enters your humidifier, ensuring that the right amount of humidity is delivered into the air every time it turns on. Usually installed by your contractor, the solenoid valve is part of the core of your humidifier, making it possible for you to adjust moisture levels with precision and accuracy.
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Product Type:
Solenoid Valve
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This item is compatible with the following Aprilaire model numbers.

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Please note: Many replacement parts have subtle differences between them and can be easily confused. Attempting to install the incorrect part voids the return coverage. If you are not completely sure your order is correct please give us a call at 1-888-757-4774.

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