I am having the same problem. Just bought a house in Michigan with a sprinkler system. I have never had a sprinkler system and am unsure how to propertly open it up, but after following the instructions on the site I have water pouring out of the top of the backflow device, which is identical to the Watts device below. I turn on the main water and water immediately begins pouring out of the top of the device around the cap, regardless of whether the valve positions to the sprinkler system are open or closed.
Any help or guidance would be GREATLY appreciated!!!