@joebruhn My thermostat arrived yesterday and I spent 4 hours struggling with this issue before I finally got it working. I had to use the adapter and have a natural gas, forced air system. My hot and cold were reversed and I didn’t have the setting to flip them. My solution was in the furnace control board wiring. My thermostat has 4 wires but the furnace had 5; there was only a blue Y at the thermostat but a red and blue Y on the furnace control. When hooking up the adapter, since it wasn’t clear, I moved both red and blue to the adapter, then connected just the adapter Y wire back to the control. By moving the red Y off the adapter and back to the control panel (so the old red Y and new adapter Y were both connected to the control terminal) my system started working correctly on the next test. Hope this helps someone!