1. Introduction and Product Overview
This manual provides essential information for the safe and efficient installation, operation, and maintenance of your Bosch 100mm Bathroom Fan. This fan is designed to provide effective ventilation in bathrooms and toilets, combating humidity, unpleasant odors, and mold growth. It features activation via a light switch for simple and practical use.

Image 1: The Bosch 100mm Bathroom Fan, a compact and elegant solution for improved indoor climate.
Key Features:
- Effective Ventilation: Silently and powerfully combats humidity, odors, and mold.
- Light Switch Activation: Simple operation, turns on and off with your light switch; this model does not include a timer.
- Integrated Backdraft Damper: Directs stale air outwards while preventing outside air from re-entering.
- Airflow Rate: 95 m³/h.
- Elegant Design: Neutral white plastic front panel integrates seamlessly into any bathroom style.
- Low Noise Level: 39 dB(A) at 3 meters. Note that noise may seem higher in tiled bathrooms due to acoustic resonances.
- Easy Installation: Designed for single-person wall-mounted installation with standard tools. Screws and wall plugs are included.
2. Safety Information
Please read all safety instructions carefully before installation and operation. Failure to follow these instructions may result in electric shock, fire, or serious injury.
- Professional Installation: Installation, electrical connection, and commissioning must only be carried out by qualified professionals in compliance with all applicable local and national regulations.
- Altitude Restriction: This appliance is not suitable for use at altitudes exceeding 2000 meters.
- Intended Use: The fan is designed to extract normal or slightly dusty air (particle size <10 µm) with low aggressiveness and humidity in temperate climates, within its specified performance characteristics.
- Electrical Connection: Ensure the main power supply is disconnected before any electrical work. The fan must be connected to a fixed electrical system using a NYM-O 2 x 1.5 mm² (H07V-K 2 x 1.5 mm²) or NYM-O 3 x 1.5 mm² (H07V-K 3 x 1.5 mm²) cable, with a maximum outer diameter of 7.5 mm, depending on equipment options.
- Damage: Do not operate the fan if the power cord or plug is damaged, or if the fan itself has been dropped or damaged.
- Children and Vulnerable Persons: This appliance can be used by children aged 8 years and above and persons with reduced physical, sensory or mental capabilities or lack of experience and knowledge if they have been given supervision or instruction concerning use of the appliance in a safe way and understand the hazards involved. Children shall not play with the appliance. Cleaning and user maintenance shall not be made by children without supervision.
3. Package Contents
Please check that all components are present and undamaged upon unpacking.
- Bosch 100mm Bathroom Fan unit
- Mounting screws
- Wall plugs
- Instruction Manual
4. Setup and Installation
The Bosch 100mm Bathroom Fan is designed for wall-mounted installation only. It requires a 102mm diameter opening for a 100mm duct.
4.1 Pre-Installation Checks:
- Ensure the installation location is suitable for a wall-mounted fan and has access to appropriate electrical wiring.
- Verify that the wall opening is approximately 102mm in diameter to accommodate the 100mm duct.
- Confirm that the electrical supply is disconnected at the main circuit breaker before proceeding.
4.2 Installation Steps:
- Prepare the Opening: If not already present, create a circular opening of approximately 102mm in the wall at the desired installation height. Ensure there is sufficient depth for the fan body and ducting.
- Electrical Connection: A qualified electrician must connect the fan to the fixed electrical system. Use a NYM-O 2 x 1.5 mm² (H07V-K 2 x 1.5 mm²) or NYM-O 3 x 1.5 mm² (H07V-K 3 x 1.5 mm²) cable, with a maximum outer diameter of 7.5 mm. Ensure proper grounding if applicable. This model is activated by a light switch, so it should be wired to the same circuit as the bathroom light.
- Mounting the Fan: Insert the fan body into the prepared wall opening. Use the provided screws and wall plugs to securely fasten the fan to the wall. Ensure the fan is level.
- Attach Front Panel: Once the fan body is securely mounted and wired, attach the decorative front panel. It typically clips or screws into place.
- Final Check: Restore power at the main circuit breaker and test the fan by activating the light switch.

Image 2: Detailed dimensions and installation view of the Bosch 100mm Bathroom Fan, highlighting wall-mount only.
5. Operating Instructions
This Bosch bathroom fan is designed for straightforward operation.
5.1 Power On/Off:
The fan is activated directly by your bathroom's light switch. When the light switch is turned on, the fan will begin to operate. When the light switch is turned off, the fan will stop.

Image 3: The fan's activation method and 100mm diameter exhaust opening.
5.2 Airflow and Backdraft Damper:
The fan features an integrated backdraft damper. This mechanism ensures that once the fan extracts stale, humid air from the room, it prevents colder outside air or drafts from entering back into the room when the fan is not operating. The airflow rate is 95 m³/h, ensuring efficient air exchange.

Image 4: Illustration of the fan's effective ventilation and backdraft prevention.
6. Maintenance
Regular maintenance ensures optimal performance and longevity of your fan.
6.1 Cleaning the Fan:
- Disconnect Power: Always ensure the electrical supply to the fan is disconnected at the main circuit breaker before cleaning.
- Remove Front Panel: Carefully unclip or unscrew the front decorative panel.
- Clean Surfaces: Use a soft, damp cloth to wipe down the front panel and the visible parts of the fan housing. For stubborn dirt, a mild, non-abrasive cleaning agent can be used.
- Clean Fan Blades: Gently clean the fan blades with a soft brush or a vacuum cleaner with a brush attachment to remove dust and debris. Avoid bending the blades.
- Reassemble: Once all parts are clean and dry, reattach the front panel.
- Restore Power: Reconnect the electrical supply at the main circuit breaker.
Do not use: Abrasive cleaners, solvents, or harsh chemicals, as these can damage the fan's plastic components.
7. Troubleshooting
If you encounter issues with your Bosch bathroom fan, refer to the following common problems and solutions.
| Problem | Possible Cause | Solution |
|---|---|---|
| Fan does not turn on | No power supply Faulty light switch Loose wiring | Check circuit breaker. Ensure light switch is on. Verify electrical connections (by a qualified electrician). |
| Fan is excessively noisy | Accumulated dust/debris on blades Loose mounting Acoustic resonance in tiled rooms | Clean fan blades (see Maintenance). Ensure fan is securely mounted. Note that 39 dB(A) is the specified noise level, and tiled rooms can amplify sound. |
| Poor air extraction | Blocked ducting Fan blades obstructed Backdraft damper stuck | Check ducting for obstructions. Clean fan blades. Inspect backdraft damper for free movement (ensure power is off). |
| Fan vibrates | Unbalanced fan blades Loose mounting | Clean fan blades to remove uneven debris. Tighten mounting screws. |
If the problem persists after attempting these solutions, please contact a qualified electrician or Bosch customer support.
8. Specifications
Technical data for the Bosch 100mm Bathroom Fan (Model 7738335623).
| Feature | Specification |
|---|---|
| Brand | Bosch Thermotechnik |
| Model Number | 7738335623 |
| Color | White |
| Product Dimensions (L x W x H) | 16 x 18 x 16 cm (6.3 x 7.1 x 6.3 inches) |
| Power | 13.5 Watts |
| Voltage | 230.0 V |
| Material | Plastic |
| Number of Speeds | 1 |
| Noise Level | 39 Decibels (at 3m) |
| Item Weight | 500 g (1.1 lbs) |
| Fan Design | Extraction Fan |
| Power Source | Corded Electric |
| Style | Light Switch Activation |
| Recommended Use | Indoor (Bathroom) |
| Mounting Type | Wall Mount |
| Airflow Rate | 95 m³/h |
9. Warranty Information
Bosch products are manufactured to high-quality standards and come with a manufacturer's warranty. Please refer to the warranty card included with your product or visit the official Bosch Thermotechnik website for detailed warranty terms and conditions applicable in your region. Keep your proof of purchase for warranty claims.
10. Support and Contact
For technical assistance, spare parts, or further inquiries, please contact Bosch customer support. You can find contact details on the official Bosch Thermotechnik website or through your local retailer.
Online Resources: Visit the Bosch Thermotechnik Store on Amazon





