Question
QUESTION: Hi, I have a 8 zone irrigation system run by a 3hp pump from a pond, and when I select zone three I get a loud buzzing noise from the pump relay but its only on that zone, all the other zones work fine. Is this a bad valve or a short in the 24v wiring? The system worked fine last year, I hope you can help!!! Thanks

ANSWER: Is it the pump relay switch that is buzzing or the valve solenoid?

---------- FOLLOW-UP ----------

QUESTION: Hi Jeff, I'm positive that its the pump start relay because the relay is located beside the pump and there are no valves with in 30ft of the pump, also the valve that is on the zone that buzzes works, I tested it with 3 9 volt batteries..

Answer
I cant undertand how the valve circuit is affecting the pump relay, but I think you need to check all of the wiring connections, and make sure the terminals at the controller are tight.  There must be some cross-connection somewhere that is causing the chatter.