I plumbed an irrigation flow valve into my hose bib. This allows me to run a conventional sprinkler or soaker hose (connected via garden hose) controlled by a timer (formerly Rainbird, soon to be OS). There is also a manual electrical switch outside the house that allows manually activating the valve from outside – so we don’t have to go to the controller every time we want to turn on the water. Is it OK to wire a channel of OS like this? The switch would essentially apply 24 VAC to the output of the triac when it is in the off state. I don’t know if that is something a triac can tolerate.
It’s not entirely clear to me how you want to wire them up. Are you basically trying to connect OS with a manual switch in parallel, in order for either to control the valve? Could you provide a diagram of the wiring?