I have a 10 year old 8 zone RainBird system that was working until about 2 weeks ago.
I was trying to test zone 5 at the valve box and noted that I could measure 24 volts when the zone was turned on until I touched the solenoid wire to the hot wire and then the volts went to zero. (not sure if this is significant)
Any help on where to go from here would be appreciated.
Thanks
You have wiring issues, pure and simple. You might have some bad splices underground. It's the bad splices, or other wire issues, that allow you to read a voltage that disappears when you try to power a solenoid from the wire at which you just read 24+ volts.