Search for: Log In Register OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Pi (OSPi) › Master Valve on Expansion Board? This topic has 2 replies, 2 voices, and was last updated 5 years, 1 month ago by gadgetboy. Viewing 3 posts - 1 through 3 (of 3 total) Author Posts August 2, 2016 at 10:54 am #43615 gadgetboyParticipant I’m replacing a RainBird ESP-Me controlling 11 zones (wiring photo attached) with an OSPi + an Expansion Board. I’d like to keep the physical zone numbering consistent with the original wiring so that it will match the diagram from the installer. Is there any reason that I cannot/should not map the MV to a port on the Expansion Board, say, on zone 12? Attachments:sprinkler_wiring.jpg August 4, 2016 at 12:01 am #43647 RayKeymaster You can map the MV to zone expander. OpenSprinkler firmware now supports using any available zone, including those on expansion boards, as master zone/valve. August 4, 2016 at 7:43 am #43652 gadgetboyParticipant Perfect. Thanks, Ray! Author Posts Viewing 3 posts - 1 through 3 (of 3 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In OpenSprinkler › Forums › Hardware Questions › OpenSprinkler Pi (OSPi) › Master Valve on Expansion Board?