I have a Watts 800M4FR PVB that's acting up from time to time. At the beginning of the summer, I did buy the full replacement kit and installed that. However now that my system is operational, it still does this from time to time:
http://youtu.be/ExNRjmqMKjo
Sometimes it will do that indefinitely and other times it will stop the pulsating and water will just flow from the cap. This normally happens at the beginning of my watering cycle when my first zone starts. I haven't been able to reproduce this through a manual start of that zone. And normally when this happens, if I just shut the valve going into the PVB, then open it again, the PVB seems to "catch" and it no longer leaks and functions normally through the entire watering cycle.
Any thoughts on what could be causing this? Thanks!