Okay. Thanks for your suggestions.
A zone quit working so I called the repair man. According to him, I have a bad wire that carries some voltage, but not enough to activate the valve. He said a tracer wouldn't find the break because it still transmits some voltage, so I either have to replace the valve with a separate, battery-operated unit, or dig a trench and run new wire all the way around the house. I'm looking for a second opinion, because I don't like either of those options... Thanks for you help.
