It's definitely channel 1, or at least the input marked HT1, see the original photo. I've set the threshold to 0.1 and enabled all three channels just in case, but they're still all showing 0.0 degrees/humidity.
I've just tried changing the sensor on channel 1 to DHT11 (with the other two channels left at DHT22) and now channel 1 is showing temperature 25 degrees (which sounds right) and humidity 2% (which is definitely wrong), but at least it's not zero any more. If I set the other channels to DHT11 then it goes back to zero again. If I set channel 2 to DHT11 and the others to DHT22 then it's also still zero. Finally, setting channel 1 = DHT11, channel 2+3 = none gives a reading of 25 degrees, 2% humidity.
The sensor is definitely a DHT22 (AM2302), not a DHT11.
As an additional note, I'm not using a 10k pullup because this post said there's one built-in on the board.
I've just tried changing the sensor on channel 1 to DHT11 (with the other two channels left at DHT22) and now channel 1 is showing temperature 25 degrees (which sounds right) and humidity 2% (which is definitely wrong), but at least it's not zero any more. If I set the other channels to DHT11 then it goes back to zero again. If I set channel 2 to DHT11 and the others to DHT22 then it's also still zero. Finally, setting channel 1 = DHT11, channel 2+3 = none gives a reading of 25 degrees, 2% humidity.
The sensor is definitely a DHT22 (AM2302), not a DHT11.
As an additional note, I'm not using a 10k pullup because this post said there's one built-in on the board.