1. Product Overview
The Vacplus CAST-300A is an ultrasonic aroma humidifier designed to improve air quality and create a relaxing atmosphere. It utilizes ultrasonic vibrations to produce a fine mist, effectively humidifying the air and preventing skin dryness. This device also functions as an aroma diffuser, allowing you to add essential oils for aromatherapy benefits. It features a 300ml water tank, a 7-color LED night light, and an automatic shut-off function for safety when water levels are low.

The Vacplus CAST-300A humidifier, showcasing its compact design and the range of 7 LED light colors available, including red, cyan, yellow, white, pink, green, and blue.
2. Product Components
Familiarize yourself with the parts of your Vacplus humidifier:

An exploded view diagram illustrating the main components of the Vacplus humidifier: the mist vent, outer cover, indicator lights, base, inner cover, water tank with air outlet, water level line, and touch control buttons.
- Mist Vent: Where the mist is released.
- Outer Cover: The decorative top cover of the humidifier.
- Inner Cover: Located beneath the outer cover, protecting the water tank.
- Water Tank: Holds up to 300ml of water. Features a water level line and air outlet.
- Base: Contains the electronic components and touch control buttons.
- Touch Buttons: Controls for mist and light functions.
- Indicator Lights: Show current operating status.
3. Safety Precautions
- Always place the humidifier on a flat, stable surface.
- Do not tilt or move the humidifier while it is operating or contains water.
- Keep out of reach of children and pets.
- Use only purified or distilled water to prevent mineral buildup and ensure optimal performance.
- Do not add water directly into the mist vent.
- Unplug the device before cleaning or refilling.
- The humidifier features an automatic shut-off function when water levels are low to prevent dry burning.
- Avoid placing the humidifier near heat sources or in direct sunlight.
4. Setup Instructions
Follow these steps to set up your Vacplus humidifier:
- Remove Covers: Gently lift and remove the outer cover, then the inner cover, from the base of the humidifier.
- Connect Power: Insert the power adapter into the DC power port located at the bottom of the humidifier base.
- Add Water and Essential Oil: Fill the water tank with up to 300ml of purified or distilled water. For aromatherapy, add 4-5 drops of your preferred essential oil directly into the water. Do not exceed the maximum water level line.
- Replace Covers: Carefully place the inner cover back onto the water tank, ensuring it is properly seated. Then, replace the outer cover.

A four-panel image demonstrating the setup process: 1. Removing the outer and inner covers. 2. Connecting the power adapter to the base. 3. Filling the 300ml tank with water and adding essential oil. 4. Reattaching the inner and outer covers.
5. Operating Instructions
Your Vacplus humidifier is designed for simple operation:
Mist Control
- Power On/Off: Press the mist button (usually indicated by a mist icon) once to turn on continuous mist. Press again to cycle through mist modes (if available) or to turn off.
- Timer Function: Some models may have a timer function. Refer to the icons on the device for specific timer settings (e.g., 1H, 3H, 6H).
LED Light Control
- Turn On/Off Light: Press the light button (usually indicated by a light bulb or sun icon) once to turn on the 7-color cycling LED light.
- Select Color: Press the light button repeatedly to cycle through the individual colors or to fix it on your preferred color.
- Turn Off Light: Continue pressing the light button until the light turns off.
Automatic Shut-off
The humidifier is equipped with an automatic shut-off feature. When the water level in the tank becomes too low, the device will automatically power off to prevent damage and ensure safety. This allows for worry-free use, even during extended periods like overnight sleep.

The Vacplus humidifier emitting a soft yellow light, highlighting its quiet operation, with an inset image of a sleeping baby, suggesting its suitability for use in a nursery or bedroom.
6. Maintenance
Regular cleaning and maintenance are crucial for the longevity and efficient operation of your humidifier.
- Daily Maintenance: Empty any remaining water from the tank and wipe it dry after each use.
- Weekly Cleaning: Unplug the humidifier. Remove the covers and water tank. Gently clean the inside of the water tank and the ultrasonic vibrating plate with a soft brush or cloth. You can use a mild detergent or a mixture of water and white vinegar to remove any mineral buildup or scale. Rinse thoroughly with clean water.
- Preventing Water Scale: To minimize water scale accumulation, always use purified or distilled water. If tap water is used, scale buildup may occur more frequently, potentially affecting mist output. Periodic maintenance is highly recommended to prevent this.
- Drying: Ensure all parts are completely dry before reassembling and storing the humidifier.
7. Troubleshooting
If you encounter issues with your Vacplus humidifier, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No mist or low mist output | Low water level Water scale buildup Mist vent blocked | Refill water tank Clean the water tank and ultrasonic plate Ensure mist vent is clear |
| Device does not turn on | Not plugged in No power Water tank empty (auto shut-off) | Check power connection Verify power outlet Refill water tank |
| Unpleasant odor | Stagnant water Dirty water tank | Empty and clean water tank regularly Use fresh, purified water |
| Water leakage | Covers not properly sealed Overfilled water tank | Ensure inner and outer covers are correctly placed Do not exceed max water level |
8. Specifications
| Feature | Detail |
|---|---|
| Brand | Vacplus |
| Model Number | CAST-300A |
| Capacity | 300ml |
| Material | Wood (base), Plastic (tank/covers) |
| Color Options | Black, Beige (Wood Grain) |
| LED Light | 7-color changing LED |
| Operation Mode | Continuous |
| Safety Features | Automatic dry-burn prevention shut-off |
| Package Size | 16.8 x 13.1 x 12.9 cm |
| Package Weight | 0.46 kg |
| Battery Usage | No |
9. Warranty and Support
For warranty information or technical support, please refer to the product packaging or contact Vacplus customer service directly. Keep your purchase receipt as proof of purchase.