I have searched for answers to this with no luck. I recently replaced my quality looking heavy metal pvb that had hammered on occasion, and leaked for a few seconds between zones with a much cheaper looking toro pvb in plastic. ( I could not find a decent one at the time) Problem is now worse...On initial startup for the day it leaks horribly, and will not stop till I shut the valves, open the first fast then the second slowly, but then does it again for the next zone. pressure is about 45-55 ( ...
