OPERATING INSTRUCTIONS – MODELS 400, 500, 600 & 700

The Digital Humidifier Control offers two modes of operation, Automatic or Manual. An explanation of both modes follows. (See Figure A on page 5 for Automatic Mode. See Figure B on page 6 for Manual Mode.)

When in the Automatic Mode, this system offers the following benefits:

•You will always receive the optimum amount of humidity so that your home and its furnishings are always protected from the damaging effects of excess condensation or low humidity during the heating season. The Control automatically adjusts your home’s RH based on the outdoor temperature, increasing the time maximum comfort is maintained.

•Simple operation with few adjustments. The Control eliminates the need to manually adjust the control when outdoor temperature changes. It also eliminates the need to turn the dial setting to “OFF” during the summer season.

DIGITAL HUMIDIFIER CONTROL INDICATOR LIGHTS

Call Dealer for Service: The red light indicates that the humidifier is not operating normally and that service is required.

Change Water Panel: The yellow light indicates that it is time to change the Water Panel in the humidifier.

Humidifier On: The green light indicates that the humidifier is operating normally.

AUTOMATIC MODE

FIGURE A – Automatic Mode

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Your Aprilaire Humidifier Control is installed in the cold air return duct. During the first heating season, your Humidifier Control needs to be set initially to match your home’s condition. Please follow these steps when adjusting your control (refer to Figure A).

1.Turn the dial setting knob to “5,” which is within the normal range. During the next 24-48 hours it may be necessary to adjust the dial for more or less humidity, depending on your personal comfort and home’s requirements. Refer to TABLE 3 – Operation Guide.

2.During the coldest portion of the first heating season, minor adjustments may be necessary. This is dependent upon your home’s construction. Refer to TABLE 3 – Operation Guide.

The RH in your home will now be accurately controlled to meet your needs and should not need further adjustment during future heating seasons. Make note of the dial setting in the event you temporarily move the knob to “OFF” when performing annual maintenance of your Aprilaire humidifier.

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Aprilaire 400M Operating Instructions Models 400, 500, 600, Digital Humidifier Control Indicator Lights, Automatic Mode
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400, 600, 400M specifications

The Aprilaire 400 is a high-performance whole-home humidifier designed to enhance indoor air quality and provide superior comfort throughout your living spaces. As part of the Aprilaire family, known for their commitment to creating healthier environments, this model stands out due to its innovative features and advanced technologies.

One of the main characteristics of the Aprilaire 400 is its capacity to humidify homes effectively, covering an area of up to 4,000 square feet. This makes it ideal for large living spaces, ensuring that every room benefits from balanced humidity levels. The humidifier operates seamlessly with the home’s existing heating and cooling systems, requiring no additional maintenance, making it a hassle-free solution for homeowners.

A prominent feature of the Aprilaire 400 is its self-regulating technology. This unit uses a built-in humidistat that senses the moisture levels in your home and adjusts the humidification output accordingly. This ensures optimal humidity—typically between 30% and 50%—which can help reduce issues related to dry air, such as dry skin, irritated sinuses, and static electricity.

Another key benefit of the Aprilaire 400 is its evaporative design, which utilizes a water panel rather than a traditional water tank. This allows for efficient moisture dispersion, as the humidifier draws in dry air, passes it through the water panel, and releases it back into the living space as humidified air. The water panel is replaceable and designed for annual maintenance, promoting long-term functionality and hygiene.

The Aprilaire 400 also incorporates a simple installation process. With compatibility for various heating systems, including forced air and hydronic, it can be integrated into most homes without significant modifications. Its compact design is another advantage, ensuring it can fit unobtrusively in your home, maintaining the aesthetic of your space.

Overall, the Aprilaire 400 whole-home humidifier is a reliable solution for maintaining optimal humidity levels, fostering a healthier living environment, and enhancing overall comfort. With its advanced features, ease of use, and efficient operation, this humidifier is a smart investment for any homeowner aiming to improve indoor air quality and promote well-being.
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