1. Introduction
Thank you for choosing the KOSTTE Instant Baby Bottle Warmer and Formula Maker. This device is designed to simplify baby feeding by providing warm water at precise temperatures for formula preparation. Please read this manual thoroughly before use to ensure proper operation, safety, and maintenance.

Image 1.1: The KOSTTE Instant Baby Bottle Warmer, showing its main unit and a baby bottle receiving dispensed water.
2. 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 appliance.
- Do not touch hot surfaces. Use handles or knobs.
- To protect against electrical shock, do not immerse cord, plugs, or the appliance in water or other liquid.
- Close supervision is necessary when any appliance is used by or near children.
- Unplug from outlet when not in use and before cleaning. Allow to cool before putting on or taking off parts, and before cleaning the appliance.
- Do not operate any appliance with a damaged cord or plug, or after the appliance malfunctions or has been damaged in any manner. Contact customer service for examination, repair, or adjustment.
- The use of accessory attachments not recommended by the appliance manufacturer may cause injuries.
- Do not use outdoors.
- Do not let cord hang over edge of table or counter, or touch hot surfaces.
- Do not place on or near a hot gas or electric burner, or in a heated oven.
- Always attach plug to appliance first, then plug cord into the wall outlet. To disconnect, turn any control to 'off', then remove plug from wall outlet.
- Do not use appliance for other than intended use.
- Ensure the water tank is securely placed before operation.
- Only use distilled or purified water to prevent mineral buildup.
3. Product Components
Familiarize yourself with the parts of your KOSTTE Instant Baby Bottle Warmer:
- Main Unit with Dispenser Spout
- Detachable Water Tank (1.5L / 50 oz capacity)
- Control Panel (Temperature Selection, Night Light, Power/Dispense Button)
- Power Cord

Image 3.1: Key features of the warmer, including non-slip base, night light, water tank capacity, and material safety.
4. Setup
- Unpack: Carefully remove all components from the packaging.
- Clean: Before first use, wash the detachable water tank and dispenser spout with warm, soapy water. Rinse thoroughly and dry. Wipe the main unit with a damp cloth.
- Place: Position the warmer on a stable, flat, heat-resistant surface, away from direct sunlight or heat sources. Ensure adequate ventilation.
- Fill Water Tank: Fill the detachable water tank with distilled or purified water up to the MAX line. Do not overfill.
- Attach Tank: Place the filled water tank securely onto the main unit.
- Connect Power: Plug the power cord into a grounded electrical outlet. The device will emit a beep and the indicator lights will illuminate briefly.
5. Operating Instructions
The KOSTTE Instant Baby Bottle Warmer is designed for quick and convenient formula preparation.

Image 5.1: Step-by-step guide for preparing a baby bottle.
- Power On: Press the power button (usually combined with the dispense button) to turn on the device.
- Select Temperature: Use the temperature selection button to cycle through the available preset temperatures: 100°F (38°C), 113°F (45°C), and 131°F (55°C). The corresponding indicator light will illuminate.
- Wait for Heating: The device will begin heating the water to the selected temperature. This process is typically fast. The display or indicator light will show when the target temperature is reached. The device maintains this temperature for 24 hours.
- Dispense Water: Place a clean baby bottle under the dispenser spout. Press and hold the dispense button to release warm water into the bottle. Release the button when the desired amount of water is reached.
- Add Formula: Add the appropriate amount of formula powder to the warm water in the bottle, according to formula manufacturer instructions.
- Mix: Secure the bottle cap and shake well until the formula is fully dissolved.
- Check Temperature: Always test the temperature of the formula on your wrist before feeding your baby to ensure it is safe and not too hot.
- Night Light Function: Press the night light button to activate or deactivate the gentle night light feature, useful for nighttime feedings without disturbing sleep.

Image 5.2: Dispensing warm water into a baby bottle.
6. Temperature Settings
The KOSTTE warmer offers three preset temperature options to cater to different needs:
- 100°F (38°C): Ideal for general warm water dispensing.
- 113°F (45°C): Recommended for formula preparation.
- 131°F (55°C): Suitable for warming oatmeal or other baby foods that require a higher temperature.
The device maintains the selected temperature for 24 hours, ensuring warm water is always available.

Image 6.1: Visual representation of temperature settings for different uses.
7. Maintenance and Cleaning
Regular cleaning ensures optimal performance and hygiene.
- Daily Cleaning: Empty any remaining water from the tank daily. Wash the detachable water tank with warm, soapy water, rinse thoroughly, and dry completely before reattaching.
- Exterior Cleaning: Wipe the exterior of the main unit with a damp cloth. Do not use abrasive cleaners or immerse the main unit in water.
- Descaling (Monthly or as needed): Mineral buildup can affect performance. To descale, mix 1 cup of white vinegar with 1 cup of water. Pour the solution into the empty water tank. Let it sit for 30 minutes to an hour. Do not heat the vinegar solution. Empty the solution and rinse the tank thoroughly several times with fresh water. Run a cycle with fresh water to flush out any residual vinegar taste.

Image 7.1: The detachable water tank being removed for easy cleaning.
8. Troubleshooting
If you encounter issues with your KOSTTE warmer, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| Device does not power on. | Not plugged in; power outlet issue; device malfunction. | Ensure power cord is securely plugged into a working outlet. Try a different outlet. If issue persists, contact customer support. |
| Water is not heating. | Incorrect temperature selected; heating element malfunction. | Verify the desired temperature is selected. Ensure the water tank is properly seated. If no heat, contact customer support. |
| Water is not dispensing. | Water tank empty; dispenser spout blocked; dispense button not pressed correctly. | Check water level in the tank. Ensure the dispense button is pressed and held. Check for any blockages in the spout. |
| Water has an unusual taste/smell. | Mineral buildup; residual cleaning solution. | Perform descaling process. Rinse tank thoroughly. Ensure only distilled or purified water is used. |
9. Specifications
| Feature | Detail |
|---|---|
| Model Number | 3900 |
| Product Dimensions | 5.91 x 5.91 x 14.17 inches |
| Item Weight | 3.47 pounds |
| Material Composition | ABS |
| Material Free | BPA Free |
| Water Tank Capacity | 1.5L / 50 oz (Detachable) |
| Temperature Settings | 100°F (38°C), 113°F (45°C), 131°F (55°C) |
| Keep Warm Function | 24 Hours |
| Additional Features | Night Light, Instant Water Dispensing |
| Care Instructions | Hand Wash (Detachable Tank) |
| Batteries Required | No |
10. Warranty and Support
KOSTTE products are manufactured to high-quality standards. For warranty information, technical support, or any questions regarding your product, please refer to the warranty card included with your purchase or contact KOSTTE customer service directly through their official website or the retailer where the product was purchased.





