I threw together a web app to help winterize an irrigation system controlled by Rachio using an attached air compressor. It’ll cycle through your zones (with a wait time in between) for you. It runs entirely in your browser and does not send your data anywhere other than Rachio.
I suggest using this on a computer (not phone) which is set to not go to sleep. Feel free to submit issues / suggestions in the GitHub repo (preferred) or here, though I can’t promise I’ll be able to make updates very often.