Yes, you can absolutely replace your System Sensor 2400 with the System Sensor 2W-B. The 2W-B is designed to be a compatible replacement for older models like the 2400, offering improved performance and reliability. Since both detectors are 2-wire models, the installation process should be straightforward without any compatibility issues. Just make sure to follow the manufacturer’s guidelines and wiring instructions provided with the 2W-B for proper installation and functionality. If you have any specific concerns or questions during the replacement process, feel free to reach out for assistance.