Introduction
This manual provides detailed instructions for the safe and efficient operation, maintenance, and troubleshooting of your Air Innovations MH-505A Ultrasonic Cool Mist Humidifier. Please read this manual thoroughly before first use and retain it for future reference.
Important Safety Instructions
To reduce the risk of fire, electric shock, or injury, always follow these basic safety precautions:
- Read all instructions before using the humidifier.
- Place the humidifier on a firm, flat, waterproof surface at least 12 inches away from walls and 3 feet from heat sources.
- Do not operate the humidifier if the cord or plug is damaged.
- Always unplug the unit before filling, cleaning, or moving it.
- Do not immerse the base in water.
- Keep out of reach of children and pets.
- Use only clean, cool tap water or distilled water.
- Do not add essential oils directly into the water tank; use the designated aroma tray.
Product Overview
Familiarize yourself with the components of your Air Innovations MH-505A Humidifier.

Image 1: Front view of the Air Innovations MH-505A Humidifier, showcasing the digital display and control buttons.
Main Components:
- Water Tank: Large capacity tank for water storage.
- Base Unit: Contains the ultrasonic nebulizer and electronic controls.
- Mist Nozzle: 360-degree rotating nozzle for mist direction.
- Digital Display: Shows current humidity, mist settings, and timer.
- Control Panel: Buttons for power, mist level, timer, humidistat, and dimming.
- Aroma Tray: For use with essential oils (do not add oils directly to water tank).
- Permanent Ceramic Filter: Located inside the water tank, helps purify water.
Setup and First Use
- Unpack: Carefully remove all packaging materials and place the humidifier on a flat, stable surface.
- Fill Water Tank:
- Remove the water tank from the base unit using the top handle.
- Unscrew the tank cap and fill the tank with clean, cool tap water or distilled water. Do not fill with hot water.
- Securely replace the tank cap and place the tank back onto the base unit. Ensure it is seated correctly.
- Position: Place the humidifier in the desired location, ensuring the mist nozzle is directed away from walls and furniture.
- Plug In: Connect the power cord to a standard electrical outlet. The digital display will illuminate briefly.

Image 2: The Air Innovations MH-505A Humidifier operating in a room, demonstrating its compact size and mist output.
Operating Instructions
Control Panel Functions:
- ON/OFF Button: Press to turn the unit on or off.
- MIST Button: Cycles through 4 mist output settings (Low, Medium, High, Max).
- HUMIDISTAT Button: Allows you to set a desired humidity level (e.g., 40% to 95% RH). The unit will automatically turn on/off to maintain this level.
- TIMER Button: Sets an automatic shut-off timer for 1 to 24 hours.
- DIM LED Button: Dims or turns off the digital display light for nighttime use.
- AROMA TRAY: Pull out the small tray located at the bottom of the unit. Add a few drops of essential oil to the aroma pad (not directly into the water tank). Push the tray back in.
Using the Humidifier:
- Press the ON/OFF button to start the humidifier.
- Adjust the mist output using the MIST button to your preferred level.
- To set a target humidity, press the HUMIDISTAT button repeatedly until your desired percentage is displayed. The unit will cycle to maintain this level.
- Optionally, set a timer for automatic shut-off using the TIMER button.
- If using essential oils, add them to the aroma tray as described above.
- For undisturbed sleep, press the DIM LED button to reduce display brightness.
Maintenance
Regular cleaning is essential for optimal performance and hygiene.
Daily Maintenance:
- Empty and rinse the water tank and base unit with fresh water.
- Allow all parts to air dry before reassembly or storage.
Weekly Maintenance (Descaling):
- Unplug the unit.
- Remove the water tank.
- Pour 2 cups of undiluted white vinegar into the base reservoir.
- Let it soak for 20 minutes.
- Use a soft brush (a small brush is often included, attached to the inside of the base) to gently clean mineral deposits from the nebulizer and other surfaces.
- Rinse the base thoroughly with clean water until the vinegar smell is gone.
- Clean the ceramic filter by rinsing it under running water.
Storage:
Before storing, ensure all parts are clean and completely dry. Store in a cool, dry place.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No Mist Output |
|
|
| White Dust Around Unit | Hard water used. | Use distilled or demineralized water. Clean the ceramic filter regularly. |
| Unusual Odor |
|
|
| Unit Leaks Water |
|
|
Specifications
- Model: MH-505A
- Brand: Air Innovations
- Capacity: 1.37 Gallons (5.2 Liters)
- Run Time: Up to 70 hours on low setting
- Coverage Area: Up to 400 sq. ft.
- Operation Mode: Ultrasonic Cool Mist
- Special Features: Digital Display, Programmable Humidistat, 24-hour Timer, Aroma Tray, Permanent Ceramic Filter, Auto Shut-off
- Product Dimensions: 9.25"D x 6.5"W x 12.75"H
- Item Weight: 3.5 Pounds
Warranty and Customer Support
For warranty information or technical assistance, please contact Air Innovations customer support. Refer to the product packaging or the official Air Innovations website for the most current contact details.
Website: www.air-innovations.com