1. While the built-in support for master zones only handles 2 masters, you can always achieve similar effects by manually schedule master zones. Specifically, OpenSprinkler supports ‘parallel zones’, so if you need 3 master zones, you can just set those three zones as ‘parallel’ (i.e. turn off ‘sequential’ flag), then manually schedule each in a program with other zones. This is not as convenient as automatic scheduling of master zones as the two built-in ones do, but it does allow you to achieve more than 2 master zones.
2. Each main controller only supports 1 flow meter at the moment (while there are two sensor ports, only Sensor 1 port supports flow sensor). If you want 3 independent flow meters, you will need 3 main controllers.
3. OpenSprinkler support sequential zone operations. Yes it can work with IFTTT to trigger an action when temperature forecast is above some threshold. This can be done by setting up an IFTTT applet, where the trigger is temperature condition, action is a webhook command sent to OpenSprinkler, you can use the ‘run a program’ API to trigger a specific program to run when the temperature condition is met.
4. By default we use DarkSky weather data. You can check DarkSky website for weather data reliability near your location.
5. OpenSprinkler 3 now supports both WiFi and wired Ethernet. If you have powerline Ethernet adapter, you can surely use wired Ethernet on OpenSprinkler.