Question
The zone 4 on my sprinkler system doesn't turn on and the display on the box says " 4 FUS " whenever I try to turn it on. I took the panel off and looked around inside because I assumed that "FUS" meant fuse but I was unable to locate one. Am I barking up the wrong tree? If so what else could it be?

Answer
Hey Aaron, more than likely, "FUS" means the internal fuse (automatic reset) has tripped. What this means,, is that you have a short on the #4 valve. This is either because the solenoid has gone bad and needs replacing, or there is a short in the wire. Replace the solenoid first, and see it this is the problem. Go to www.irrigationtutorials.com and this website will show you how to replace the solenoid. Good luck and have a great day.