Problem connecting new fan to my XB7 Gateway-requires 2.4 ghz band-I've read through other threads, have more questions

As I see is a common problem, I have a new device that won't connect to my wifi network. I've read that the newer Gateways operate on both bands and automatically switch to the best option. I've read that some people split their network into two operating bands. I've read the troubleshooting should include restarting the Gateway and starting the process again, which I've done. I'm fairly sure I have other devices that require to slower band that I did not experience this issue with. Before I take the step to split the bands, I want to make sure it's really necessary. If it matters, my device is a Broan Exhaust/Ventilating bathroom fan with light. Any help appreciated. Thanks.