In one of my zones 3 of the head continue to slowly leak for a while after the zone is shut off. The three heads are at the end of the pipe and are all down a slight slope. Is there enought pressure from the water trying to run downhill in the pipe to push water out of 3 heads? They are leaking even after the main valve is shut off.
Thats what I thought but wasn't sure there would be enough pressure going downhill to make them leak. I'll double check them tonight. Is is odd that only that zone does it even though there is another zone close by that goes down almost the same grade of slope?
If your system has a master valve, then there can be some zone-to-zone drainage, and it is a random thing as to which downhill zone the water drains from.