Wire tracing maintenance and wire tracing repairs takes experience, skill, and great tools.
The art and skill of finding broken/damaged wire or missing valves is a learned skill that requires specific tools. The wire tracing tools have been refined to an art but it still requires experience to interpret properly.
Often times we can find the problems in very short order, however, sometimes it can take a while. A completely cut through the wire is easier to locate than a nicked wire. The indicator for a bad wire connection is similar to that of a broken wire. The solenoid shows very strong but allows the current to flow through to the second wire causing a ghost signal to appear, it may be necessary to cut the wire at the solenoid to prevent this.
When using a wire-tracking tool you can hear the signal strength as well as follow the null meter. The signal will be stronger on either side of the current being sent through the wire from the wire tracking tool.
After you have located the break, it is helpful to cross the path to narrow down the hot spot. Next step is to verify that you have in fact found the break or valve by digging it up. A helpful hint, be very careful to not damage the components when searching for it.
We can trace wire underground using an electronic tracer to locate valves and broken wires.
Over the years, we have been asked to do many interesting things, finding broken or damaged wires is a fun one. With the proper tools and knowledge, it can be very rewarding. Sometimes it is the experience that allows us to figure out what is wrong and how to fix it and sometimes it is the tools.