Question
This timer has shut off a couple of times, but could be restarted by pushing the reset button.  I suspect that the problem is a Toro master valve that goes to my back yard zones.  The zones in my front yard do not have a master valve.  The Toro valve is activated when any zone is on including the front yard.  The valve seems to make some swooshing noise while the front yard zones are on, but is quiet when the back yard zones are on.  The solenoid seems to be fairly hot; could that be tripping the timer?  The solenoid was replaced last fall and appears to be working fine.  Any ideas?

Answer
Hey Allen, the problem could be in the master valve solenoid, but if it was bad, and shorting out (tripping the reset button) it would normally do it as soon as the system starts. What I suspect, is that one of the other valve solenoids is the one shorting out the controller (tripping the reset button). I would suggest starting the system and let the dial rotate to each valve one at a time for about 5 minutes each, and listen for the button to trip. Lets say it goes to valve #4 and you hear the button trip, then you know you need to find valve #4 and replace this valves' solenoid. Good luck and have a great day.