IoT device requires connection to 2.4GHz

[DAVESUD]

I have an IoT device that has a setup process requiring an iPhone to via WiFi on the 2.4GHz network.   Ther is  no option in ther iPhone setup to allow selection of the network.  It automatically connects to the 5Ghz network. But the IoT device ONLY connects to the 2.4Ghz.  How do I force the iPhone to connect at 2.4GHz?  Any other ideas how to bridge this gap.

[DarrenM]

No manual way to connect to the 2.4ghz but if you go into a room far away from a unit it will have a better chance to connecting to the 2.4ghz.

DarrenM