I have an old manually-operated underground sprinkler with three zones, each opened separately with a fork. One of the zones makes a lot of noise when running–specifically, waxing and waning vibrational sounds–and I can feel the vibration in the house. This abates if I run any of the other zones or any water in the house, even at a drip. My contractor suggests that the whole zone must be dug up and replaced. Any ideas about what’s going on, and how I might fix it (or have someone else fix it) short of major excavation? Whether due to their dullness or mere bafflement at a woman wanting to understand the problem, my local hardware store is of little help.
It sounds like a resonance problem in the valve. Possibly a defective valve or possible because there is too much water pressure at the valve when that line is the only one running.
Does the problem exist if the valve is only turned part of the way on?
Yes, but it’s not as pronounced.
[plumbing novice]
It sounds like an o-ring or washer has worn out. This allows the valve to vibrate in the valve seat. When it hits the right frequency, the valve will resonate and the pipes transmit the vibration back to the house. When you change the pressure on the system, it changes the frequency and stops vibrating.
The part should cost cents, and labour should be (I would guess) less than an hour for a plumber.
You might want to contact a different contractor…
[/plumbing novice]