3/25/2013 4:03 PM
I've worked with decoders the last two courses I've been at. 1 was a toro system installed in house, the other I inherited from a contractor that had some issues, and no longer exists. I really like the simplicity and adaptability they tend to provide. It's been really easy to "modify" the irrigation system with additions and subtractions of heads to become more efficient, and not having to run anything back to a satellite. Both of these systems are from around the 2003 era, so nothing as new as the Rainbird IC's. They look pretty neat to work with though.
A couple things to consider that I've noticed when working on them after the fact.
1) Quality control with wiring detail is pretty important. Any shoddy splices, redundant tie-ins to main trunk-lines, and poor detail to decoder location if multiple valves are used per station makes trouble shooting a pain in the rear. Its a good idea to use a colored snap ring on decoder location if you have multiple valves on each address. having each hole/zone only connected electrically at one location is so much nicer when you might have to start to backtrack if and when a ground fault occurs.
2) If using multiple address packs, try as much as you can to get them closer to the complex they will be rather than running the solenoid wires over an extensive length. Use LARGE valve boxes to put these multi-packs in. There's nothing worse than not being able to get your hands and face in a location to see and work.
3) Don't skimp on surge protectors and ground rods, and know where they are. Our course is pretty unmarked unfortunately, for some odd reason. They are usually a great spot to check when wiring issues arise. I don't remember installation details, but they are usually required every so many feet of wire.
4) This goes without saying, but leave a good amount of maxi cable at each location. Sheathing is bad enough to strip without hitting wires, especially if not at eye level.
5) Bye a good locator with fault finder right away. We use a Dynatel 3373 from 3M, and its great for trouble shooting. A little clamp style milliamp meter as well. Practice with them as you are connecting to your central to read milliamp draws vs. what each hole should have given by the normal draw at rest. A simple spread sheet will help when the central starts to spike.
I've got 8 years with our Nimbus II system, and the abilities to trouble shoot from the central are great. with proper installation technique, and two capable dudes on radios, a giant ground fault that can shut down the central is found relatively easily.
Probably a little dumbeyed down, but keep it simple, and they can perform very well. With the expansion benefits you already mentioned.