1. Important Safety Instructions
Read all instructions carefully before using this appliance. 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 away from walls and heat sources.
- Do not immerse the humidifier base in water or other liquids.
- Ensure the voltage indicated on the appliance corresponds to your local mains voltage before connecting.
- Unplug the appliance from the power outlet before filling, cleaning, or moving it.
- Do not operate the humidifier with a damaged cord or plug. If the cord or plug is damaged, contact customer support.
- Keep the appliance out of reach of children and pets.
- Do not block the mist outlet.
- Use only clean, cool tap water. Do not add essential oils directly into the water tank unless specified by the manufacturer. This model allows direct addition of aroma essences/oils into the water tank.
- Do not attempt to repair or disassemble the appliance yourself. Refer all servicing to qualified personnel.
2. Product Overview
The BLACK+DECKER HM4125-B5 is an ultrasonic air humidifier designed to add moisture to the air in rooms up to 40m². It features a 4.0L water tank and an adjustable mist output.
Components
- Mist Outlet
- Water Tank Lid
- Water Tank
- Base Unit
- Control Knob (On/Off and Mist Adjustment)
- Power Cord Inlet

Figure 2.1: Overall view of the BLACK+DECKER HM4125-B5 Air Humidifier with the lid in place.

Figure 2.2: View of the humidifier with the top lid removed, revealing the water tank and internal misting components.
3. Setup
3.1 Unpacking
- Carefully remove the humidifier from its packaging.
- Remove all packaging materials and dispose of them responsibly.
- Inspect the appliance for any signs of damage. Do not use if damaged.
3.2 Placement
- Place the humidifier on a flat, stable, and water-resistant surface at least 15 cm (6 inches) away from walls and furniture.
- Ensure the mist outlet is not directed towards walls, furniture, or electronic devices.
- Avoid placing the humidifier in direct sunlight or near heat sources.
3.3 Filling the Water Tank
- Ensure the humidifier is unplugged from the power outlet.
- Remove the top lid of the humidifier.
- Pour clean, cool tap water directly into the water tank. Do not exceed the 'MAX' fill line indicated inside the tank. The tank capacity is 4.0 liters.
- Replace the top lid securely.

Figure 3.1: Filling the water tank by pouring water directly into the top opening after removing the lid.
3.4 Power Connection
- After filling the water tank, insert the power cord into the power cord inlet at the back of the humidifier.
- Plug the other end of the power cord into a suitable electrical outlet.

Figure 3.2: Connecting the power cord to the humidifier's power inlet.
4. Operating Instructions
4.1 Turning On/Off
- To turn on the humidifier, rotate the control knob clockwise from the 'OFF' position.
- To turn off the humidifier, rotate the control knob counter-clockwise to the 'OFF' position.
4.2 Adjusting Mist Output
- Once the humidifier is on, continue rotating the control knob clockwise to increase the mist output.
- Rotate the control knob counter-clockwise to decrease the mist output.
- The maximum mist output is 350 ml/h.

Figure 4.1: Adjusting the mist output using the control knob located on the front of the humidifier.
4.3 Adding Aroma Essences/Oils
This humidifier allows for the direct addition of aroma essences or oils into the water tank. Ensure the humidifier is unplugged before adding any substances.
- Unplug the humidifier.
- Remove the top lid.
- Add a few drops of your desired aroma essence or oil directly into the water in the tank. Do not overfill.
- Replace the lid and plug in the humidifier to resume operation.
5. Maintenance
Regular cleaning is essential to maintain the performance and longevity of your humidifier.
5.1 Daily Maintenance
- Unplug the humidifier and empty any remaining water from the tank.
- Wipe the inside of the water tank and the mist outlet with a clean, damp cloth.
- Refill with fresh, cool tap water before each use.
5.2 Weekly Cleaning
- Unplug the humidifier and empty the water tank.
- Remove the top lid and any internal components that are easily detachable for cleaning.
- Fill the water tank with a mixture of equal parts white vinegar and water. Let it soak for 30 minutes to an hour to loosen mineral deposits.
- Use a soft brush or cloth to gently scrub the inside of the tank and the ultrasonic transducer (the small disc at the bottom of the tank).
- Rinse all components thoroughly with clean water until the vinegar smell is gone.
- Wipe the exterior of the unit with a soft, damp cloth. Do not use abrasive cleaners.
- Allow all parts to air dry completely before reassembling.
5.3 Storage
- Before storing, ensure the humidifier is thoroughly cleaned and completely dry.
- Store the appliance in a cool, dry place, away from direct sunlight and extreme temperatures.
- It is recommended to store the humidifier in its original packaging to protect it from dust and damage.
6. Troubleshooting
If you encounter issues with your humidifier, refer to the table below for common problems and solutions.
| Problem | Possible Cause | Solution |
|---|---|---|
| No mist or very little mist | No water in tank Water tank not properly seated Mineral buildup on transducer | Refill water tank Ensure tank is correctly placed Clean the ultrasonic transducer as per maintenance instructions |
| Unusual odor from mist | New unit odor Stale water Dirty water tank | Run for a few hours to dissipate Empty and refill with fresh water Clean the water tank thoroughly |
| Water leakage | Water tank lid not sealed Humidifier placed on uneven surface | Ensure lid is securely closed Place humidifier on a flat, stable surface |
| Loud noise during operation | Low water level Humidifier not on a flat surface | Refill water tank Place humidifier on a flat, stable surface |
If the problem persists after attempting these solutions, please contact customer support.
7. Specifications
Technical Data
| Feature | Specification |
|---|---|
| Brand | BLACK+DECKER |
| Model Number | HM4125-B5 |
| Power | 30W |
| Capacity | 4.0 Liters (4000 Milliliters) |
| Room Area Coverage | Up to 40 m² (40 Square Meters) |
| Runtime | 8 to 14 hours (continuous mist) |
| Mist Output | Up to 350 ml/h |
| Operation Mode | Ultrasonic (Cool Mist) |
| Product Dimensions | 20.8 x 20.8 x 24.6 cm |
| Item Weight | 1.6 Kilograms |
| Material | Plastic |
| Color | White |
8. Warranty and Support
8.1 Warranty Information
This BLACK+DECKER HM4125-B5 Air Humidifier comes with a 2-year limited warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use. It does not cover damage resulting from misuse, accident, alteration, or unauthorized repair.
Please retain your proof of purchase for warranty claims. For detailed warranty terms and conditions, refer to the warranty card included with your product or visit the official BLACK+DECKER website.
8.2 Customer Support
For technical assistance, troubleshooting not covered in this manual, or warranty inquiries, please contact BLACK+DECKER customer support. Contact information can typically be found on the official BLACK+DECKER website or on the product packaging.





