Important Safety Instructions
Please read and save these safety instructions before operating your humidifier. Failure to follow these instructions may result in electric shock, fire, or serious injury.
- Always place the humidifier on a firm, flat, water-resistant surface at least 12 inches (30 cm) away from walls and heat sources.
- Do not immerse the humidifier in water or other liquids.
- Unplug the humidifier before filling, cleaning, or moving it.
- Do not operate the humidifier with a damaged cord or plug.
- Keep out of reach of children and pets.
- Use only clean, cool tap water. Do not add essential oils or other additives to the water tank.
- Ensure the filter is correctly installed before operation.
Product Overview
The WaterFirst MistFree Y Evaporative Humidifier is designed to provide pure, cool moisture to your environment without producing white dust. It features a polymer fiber filter and Ag+ technology for water purification.
Included Components:
- Evaporative Humidifier Unit (1)
- Polymer Fiber Filter (1)
- Ag+ Box (1)
- Power Adapter (1)
- Quick Guide (1)
- Greeting Card (1)
- User Manual (This document)

Setup
- Unpack: Carefully remove all components from the packaging.
- Positioning: Place the humidifier on a stable, flat surface. Ensure it is away from direct sunlight, heat sources, and electronic devices.
- Filter Installation:
The polymer fiber filter and Ag+ box should be pre-installed. If not, open the humidifier unit, place the Ag+ box into its designated slot, and then insert the polymer fiber filter into the water tank, ensuring it sits correctly.

Diagram illustrating the internal components, including the filter and Ag+ technology for water purification. - Water Filling:
The MistFree Y features an upgraded top-fill design. Remove the main unit (top section) to access the water tank. Fill the tank with clean, cool tap water up to the "MAX" line indicated on the water level window. Avoid overfilling.

Image showing the top-fill method for adding water to the humidifier. - Power Connection: Connect the power adapter to the humidifier and then plug it into a standard electrical outlet.
Operating Instructions
Power On/Off and Humidity Control:
The humidifier is controlled by a user-friendly knob. Rotate the knob to turn the unit on and adjust the humidification speed.
- To Turn On: Rotate the knob clockwise from the "OFF" position.
- Adjust Humidification Speed: Continue rotating the knob clockwise to increase the humidification speed. The humidifier offers 3 fan speed levels: 100ml/h, 200ml/h, and 400ml/h.
- To Turn Off: Rotate the knob counter-clockwise until it clicks into the "OFF" position.
Humidity Indicator Light:
The control knob features a color-changing ambient light that indicates the current room humidity status:
- Red Light: Indicates humidity is less than 40% RH (Dry).
- Green Light: Indicates humidity is between 40-60% RH (Comfortable).
- Blue Light: Indicates humidity is greater than 60% RH (Humid).

Sleep Mode:
To activate sleep mode, rotate the knob to the lowest humidification setting. In this mode, the humidifier operates quietly with a dim orange light, ensuring minimal disturbance for up to 15 hours.

Automatic Features:
- Auto Shut-Off: The humidifier will automatically turn off when the water level is too low.
- Water Shortage Reminder: An indicator will alert you when the water tank needs refilling.
- Automatic Drying Function: This function helps to dry the filter after use, extending its lifespan and preventing mold growth.
Maintenance
Regular maintenance ensures optimal performance and extends the lifespan of your humidifier.
- Weekly Filter Cleaning:
It is recommended to clean the polymer fiber filter 2-3 times per week. Remove the filter from the unit and wash it with laundry detergent. Rinse thoroughly and allow it to air dry completely before reinserting. This helps maintain humidification efficiency and prevents the growth of mold or bacteria.

Image demonstrating the cleaning process for the polymer fiber filter. - Filter Replacement:
The polymer fiber filter should be replaced every 3-6 months, depending on usage and water quality. Replace the Ag+ box as needed, typically with each filter replacement.
- Water Tank Cleaning:
Periodically clean the water tank to prevent mineral buildup and maintain hygiene. Use a soft cloth and mild detergent, then rinse thoroughly.
- Automatic Drying Function:
The humidifier's automatic drying function activates after use to dry the filter, which is crucial for extending its lifespan and preventing microbial growth. Ensure the unit has adequate ventilation during this process.
Troubleshooting
If you encounter issues with your WaterFirst MistFree Y Humidifier, please refer to the following common solutions:
- Humidifier not turning on: Ensure the power adapter is securely plugged into both the unit and a working electrical outlet. Check if the control knob is rotated past the "OFF" position.
- No humidification/Low output: Check the water level and refill if necessary. Ensure the filter is clean and properly installed. Increase the humidification speed using the control knob.
- Unusual odors: Clean the water tank and filter thoroughly. Replace the filter if odors persist, as it may indicate bacterial growth.
- Unit making excessive noise: Ensure the humidifier is placed on a flat, stable surface. Check for any obstructions around the fan or filter.
- White dust: This evaporative humidifier is designed not to produce white dust. If you observe white dust, it may be from another source or an issue requiring further inspection. Contact customer support.
For issues not covered here, please contact WaterFirst Customer Support.
Specifications
| Feature | Detail |
|---|---|
| Brand | WaterFirst |
| Model Name | MistFree Y Evaporative Humidifier |
| Operation Mode | Evaporative |
| Humidification Output | Up to 400ml/h |
| Water Tank Capacity | 3 Liters |
| Runtime | Up to 30 hours (on lowest setting) |
| Coverage Area | Up to 505 Square Feet |
| Fan Speeds | 3 levels (100/200/400ml/h) |
| Special Features | 360° outlet, Ag+ water purification, Polymer fiber filter, Sleep mode, Humidistat, Water Level Window, Auto Shut Off, Removable Tank, Quiet Operation, Automatic Drying Function |
| Voltage | 120 Volts |
| Wattage | 12 watts |
| Product Dimensions | 8"D x 8"W x 12.5"H |
| Item Weight | 3 Pounds |
Warranty and Support
1-Year Warranty: WaterFirst provides a 1-year warranty for this product. If you encounter any defects, please contact customer support for a replacement.
Customer Support: For assistance, inquiries, or warranty claims, please contact WaterFirst Customer Service at service@thewaterfirst.com.
Video Resources
No official product videos from the seller were available with verifiable creator type or useful content for embedding in this manual based on the provided data. Please refer to the written instructions and diagrams for guidance.