Irrigation consultant says it's an inside the house/plumber problem. Irrigation guy says valves only open and close, so what causes the pumping noise? With brief conversation with my husband, plumber says water hammer, but I'm not so sure. This is not a sound when the system goes off. I am calling another plumber, and trying to figure out how to help find what's been called a needle in a haystack.

I have a sound file, but can't figure out how to upload it

Here is what I've found so far in terms of trouble shooting the problem. I don't understand much of this and could uses some help.

noisy pipes when irrigation system is running

" I would like to break the noise down into 3 different types. One would be when the system is pressurizing or basically there is a lot of noise for few seconds when each zone is starting but then goes away. The second type would be a steady noise during the duration of the time the system is running. The last type would be only when a zone is shutting down and will only last a second or two"

I have the first type with some valves, the second with others.

Thumbing/knocking noise when valves open

" Another sprinkler company suggested replacing our lowest sprinkler heads (since our yard is sloped) with heads that have built-in anti-drain valves, so that leaking water from the heads won't cause the pipes to partially fill with air. We tried this, and we still have the thumping. Has anyone heard of this problem, and a way to solve it? "

This applies in my yard, and I have been told that there is draining water at the end of the cycle, and new valves named something like "rotors" will help. I think current valves are 25 year old rainbirds.

Thumping noise when valve turned on

"note that there is banging when the zone is first opened, and that is not water hammer. It is something of an oscillation you can sometimes see when a system is first opened in the spring, where there is no water in the zone for the supply to 'push' against. When it happens on a recurring basis, you look to make changes. Installing check valves in the heads is one obvious choice nowadays, to keep a zone full of water, so there's something to 'push' against. Throttling down a zone valve flow control is another option. Changing zone valves is another."

I have read the part about if banging when openit's not water hammer. Is that true? I've also read about checking pressure, but I think I've read I might need a professional, and I don't know what most of the rest means. Is there a "for dummies" version, or was that it?

Pumping noise when valves open

"Flow controls should be used like idle screws on engine carburetors. Throttle it down until the flow is affected, then back out half-a turn or so. Wide open is never the best way to run."

Again, is this the "for dummies" version? It's making me realize that I don't think the sound happens when I turn the valve on with the little thingy on the top of the valve. I think it is only when I turn on with the controller. But that is usally when I am in the house. When in the house, everyone in the house can hear it, and the faucets sort of pulse. Can't hear it much from outside.

Several comments in the above links about valves and diaphrams, and flow....is this really a plumber solution?