SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Water hammer shouldn't be capable of breaking anything, if the pipes are properly secured. See to that first. As to the valves, you aren't the first to notice water hammer with jartop valves. By the way, this is hammer at closing, as opposed to banging pipes at zones coming on?

Banging upon opening is a sort of oscillation, and won't depend on nozzle sizes. Closing hammer will relate to flow, and the speed of the water in the pipe, and the total length of the pipe between the main in the street and the hammering zone valve. Houses far from the street would have more hammer than houses close to the street, with everything else being equal.

If you design a system from scratch, you can properly size supply pipes, and minimize hammer. I was a long-time user of the original Richdel valves, a design that lives on as the Irritrol 205TF, and had few issues with water hammer.

Your system is asking for too much water and too fast. You should renovate it using a pro. Good luck



http://www.irrigationsolutions.com

Quoted from "Wet_Boots"

Water hammer shouldn't be capable of breaking anything, if the pipes are properly secured. ...

???? Is that really We Boots talking????

Water hammer can most certainly break something.

Water hammer is basically the release of all the energy of the moving water that was suddenly brought to a stop. That energy has to go somewhere, and one of the ways it disipates is by causing a water pressure spike in the system. Pressures can momentarily be in the hundreds of pounds per square inch, far exceeding any pressure specifications for plumbing fixtures. Securing the pipes just avoids the energy from being disipated by physically moving pipes. But that's not going to change the pressure wave that travels down the pipes. For that, that where you install one of those water hammer arrestors. They are supposed to absorb some of that pressure wave like a shock absorber. But of course pressure spikes can be so high that many times these arrestors are virtually useless. After all, when was the last time the shock absorber in your car prevented you from noticing when you ran through a 4" deep pot hole?

there can be many reasons for this as the others have pointed out. i would suggest installing an "expansion tank" on the main sprinkler line in your house. this will usually reduce the "bang". also try what is called a "minitrol" in place of your blow out point on your system. these are usually 1/2 inch male threaded devices that can easily replace your blow out plug or hose bib where you winterize your system from.

Quoted from "HooKooDooKu"

Quoted from "Wet_Boots"

Water hammer shouldn't be capable of breaking anything, if the pipes are properly secured. ...

???? Is that really We Boots talking????

Water hammer can most certainly break something.

Water hammer is basically the release of all the energy of the moving water that was suddenly brought to a stop. That energy has to go somewhere, and one of the ways it disipates is by causing a water pressure spike in the system. Pressures can momentarily be in the hundreds of pounds per square inch, far exceeding any pressure specifications for plumbing fixtures. Securing the pipes just avoids the energy from being disipated by physically moving pipes. But that's not going to change the pressure wave that travels down the pipes. For that, that where you install one of those water hammer arrestors. They are supposed to absorb some of that pressure wave like a shock absorber. But of course pressure spikes can be so high that many times these arrestors are virtually useless. After all, when was the last time the shock absorber in your car prevented you from noticing when you ran through a 4" deep pot hole?

I'm trying to deliver real-world advice. If the water hammer was extreme beyond common experience, it would have already done physical damage, like blowing a zone valve apart, or completely off its threaded supply connection.Securing the indoor plumbing from movement is job one.

Also, 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.

Quoted from "Wet_Boots"

I'm trying to deliver real-world advice. If the water hammer was extreme beyond common experience, it would have already done physical damage, like blowing a zone valve apart, or completely off its threaded supply connection.Securing the indoor plumbing from movement is job one.

No doubt that if a pipe is physically getting moved, it needs to be secured.

But over time, water hammer can lead to fatigue failure. Sure, the level of the water hammer can be low enough that 2 or 3 bangs are not going to "blow a gasket". But 2 or 3 thousand bangs over the life time of an irrigation or plumbing system might. Just because a water hammer hasn't broken something yet is NOT a reason to decide to ignore it thinking you can just live with the noise. Eventually, water hammer will break something. It's just a question of time. Will it be days, years, or decades?

Quoted from "Wet_Boots"

Also, 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.

Even with check valves I'm still getting an audible noise inside the house when a zone comes on.

My irrigation system connects to the water main at the street just after the water meter. From there it goes through a DC and then 15' of pipe to reach the manifold. I also have a pressure regulator as the water main enters the basement.

On a quiet morning, you can "hear" through out the house when the irrigation system turns on. It's not a "bang" noise, more of a "whine".

Here's what I THINK is happening and would appreciate any further insights: There is water in the pipes, but the water before the valve is about 70psi and the water after the valve is about 0.5psi. When the valve opens, that 70psi momentarily drops until the latteral gets pressurized. But in the mean time, the pressure drop propogates back to the main line and all the way to the house hold plumbing. The "whine" I am hearing is the sound of the water pipes repressurizing. The whole thing happens in about 1 second.