Touch - US Version Air Conditioning issue and general first thoughts

The relay is simply on or off. Is your HVAC system a 2-stage system that starts slowly if only a little is needed but if more heating/cooling is needed it goes to stage-2 where full power is used?

That does not make sense as Fing uses ping too. If Fing does not find it, you shouldn’t too. 2 possible scenarios are here:

  1. Have you assigned a static IP to Pi? If not, the IP has changed and you ping another device in the network. How to do you access the Openhab interface? Using the IP or via myopenhab.org (cloud connection if you enabled it)?
  2. You use Fing on a separate device than you try pinging and the 2 devices are connected to separate networks. One network (the one pinging) is shared with the HestiaPi and the other is isolated (Fing).

Having said that I must admit that since we migrated to Raspbian Stretch we do see some weird issues reported from time to time where troubleshooting is “impossible”. Moving back to Jessie (images 9.x) will be reconsidered if pilot users confirm stability is restored for a 1-2 month period. If you decide to use a 9.x image you will have to enter your WiFi credentials in a different way explained in the image page. We know moving backwards to a previous version may not be a desirable decision but if Pi Zero W can support that much weight, then we need to consider that option too.