Question
I have a hydrotek 6000 with 4 zones. When the system is not running, water seeps out from the valve cover and from several sprinkler heads. When the sprinklers come on, everything works fine - good pressure and zones change correctly. What could be causing the seepage? Thanks.  

Answer
It is probably from a valve that is not closing all the way because it has some debris in it, or has a damaged diaphragm.  Locate the valve, turn off the water to the system, and carefully dissemble the valve by removing the top.  Clean the inside of the valve of any debris you find, and inspect the diaphragm for holes or tears, and replace it if you find any.  Then reassemble the valve parts and try it out.  Its not a hard as it sounds.