So, I'm baffled and haven't been able to find an answer anywhere...
After the winter we turned on our sprinkler system yesterday (turned on main valve slowly, not fast), and all 3 zones looked good, no visible problems at all. Haven't made any changes or fixes to the system, so I was assuming we were up and running just fine.
But then we noticed a lingering pipe noise whenever we used any water in the house (any toilet, faucet, whatever) --- we had "groaning pipes" in the past, and was able to make that go away through some combination of turning on all water everywhere to flush things out and adjusting the pressure reducer valve (though by the end the pressure reducer valve was set back to the original setting, and the noises had stopped).
Anyway, this morning we noticed that the pipe noise was actually Zone 1 coming on for a while after we used ANY water source in the house --- usually it would come on for just a few minutes then trickle out. The whole system is "off" at the controller.
Is it some kind of excess water pressure problem forcing a valve open? Has a valve gone bad?
FYI, I'm fairly amateur so will call in a pro if this goes too far over my head...
Thanks for any help!