Greetings: I would like to add a new valve to my existing system WITHOUT running a new wire. I'm considering 1) the "add-a-zone" product; 2) the "doubler" product; or 3) something else? It looks like the add-a-zone is more flexible (and a tish cheaper). Does it really work? Are there long term issues? Am I wasting my money? Is there a better product out there? Thanks in advance! Jim
