Bingo! That was the problem. I assumed the gravity setting would be a local setting unaffected by pairing. The receiver wasn't pairing because the hub had been on for too long. Rebooting the hub allowed them to pair and I was able to set it into gravity mode.
Thanks, petit_pablo.
Hello, I had the bright idea to install a Hive system for my aging mother whilst cooking the turkey. Turkey is done, but not Hive. I have installed the hub and receiver. I haven't yet installed the thermostat. It is a gravity fed system.
The problem is, I can't switch the receiver/controller to...