Water Hammer

[smily]

Our 27 Overlander has a shureflo pump with plastic water lines connected to it.

The pump works very good but man you can hear the water hammer, (loud noise to those who dont know what water hammer is), It sounds like a loud shudder through out the AS.

I have looked around for info on this but I have not seen any good solutions.

Is there a way to eliminate this noise?
Insulation will do very little to dampen this noise being that you can hear it through out the trailer.

The pump is mounted on shock absorbers and there seems to be plastic pipes between the pump and th original hard lines, (I think they are copper not sure).

I have heard of methods used in homes that provide for "vapor lock or air lock".

Does anyone have any ideas or suggestions?

Thanks,
Smily

[thenewkid64]

Smily,

Check out this thread

http://www.airforums.com/forum...t=water+hammer

[smily]

Okay,
I have been to Water Hammer thread.

I did not see where any one recommended the location to install Accumulator.

Does it matter.? I am guessing somewhere near the pump?
or should it be at the farthest point from the pump?

I am going to change my water lines to the pump from stiff plastic, (PEX), to soft flexible lines.

Unlike some of the post' at the repective thread, my noise actually starts out loud and dwindles as the pressure builds up.

I read at the thread that typically the noise starts out low and builds up relative with the pressure.

My noise actually stops whaen the pump stops.

I find it hard to believe that the impellar makes this much noise.

The noise is very loud. I am concerned that the noise will actually scare our infant.

Smily

[sovereign]

that's the way the waterpump sounds on my wife's 36ft fourwinds,but it uses one of those surflo pumps, the kind where the motor and pump are one assembly.but the pump on my a/s is belt driven and right now it does'nt work. well it runs and i can see water trying too fill the see thur filter ,but it can't make it . do you know what the problem could be?

[uwe]

Hi Smily,

It's not the impeller making the hammering noise, but rather the impeller compressing the water, pumping it, that is causing a strong pulsation in the copper lines, which in turn causes the lines to rattle. You might try and find the places where the lines rattle against the trailers interior, and put foam or other dampening material around it, or secure them better. The accumulator typically goes near the pump, and it's job is to store pressurized water, so it can deliver instant water pressure without the pump having to start up immediately. I believe that the water hammering suppression is almost like a pleasant side effect of the accumulator. The bladder inside it absorbs and neutralizes the water pulses, much like a shock absorber.
I hope that the accumulator installation together with securing your copper water lines inside tha trailer will make the water lines nice and quiet, so your infant will also enjoy airstreaming !

[smily]

Sovereign,

Yes I think I know what the problem is. I had the same situation.

All of the valves under the sink, ( three in my Overlander), have to be in the shut position. if any of the valves are open, the pump will run but will not build up pressure.

I am not certain if all valves have to be closed but I know that at least one of them is crucial to operation of water being pumped from the resevoir. I know that is sounds wierd but the valve that I have to insure is closed is the one that actually goes to the resevoir, at least it looks like it does.

I believe two of the three valves are for draining and winterization.

Give it a shot with all of the valves closed.

Good luck,

Smily

[smily]

Okay,
Been a while since this thread originated but i have finally bought an acumulator at the Rally flea market this weekend.
It is the Shurflo model.

I got some advice on pressurizing the unit to 20 lbs with a bicyle tire pump but I am going to ask the Jury again about the locaion f the accumulator to be installed.

I see where UWE says to install near pump but I checked a site on Water hammer disipation and they said to install half way to farthest valve.

I am ready to install but I am looking for opinions on where to install the unit.

Any takers?

Smily

[Action]

Ken,

I have seen accumlators mounted in boats in a variety of locations. However most have been near the pump.

>>>>>>>Action

[uwe]

Smily,

I figured it is supposed to go near the pump, because this is where you can get to it easily, and it's also where it's shown on the literature. It probably matters only little where it goes, as the pressure surges are in the entire water supply. But if they originate from the pump, then the accunulator should be close to it as to neutralize the water pulses. The accumulator will also store a little bit of water under pressure, so initial flow at the faucets should be smoother, with the pump running a little bit less, especially when usng the faucet for short times only.
Good luck!

[smily]

I finally installed that accumulator and it worked GREAT!

I mounted it right next to the pump under the galley sink.

I also mounted the whole assembly to a rubber pad. The pad is about 1/2 inch thick and dense.

You can hear the pump but absolutely no water hammer.

Smily

[trailertrash]

Those ShurFlo's are pretty nasty- depending on how old they are. Whenever I replace one, I use the one that is tops in the yachting industry, made by Jabsco, and the prices are about the same. I use one that pumps 3.5 GPM, so I have nice pressure, and its totally quiet compared to the Hammer- you can hear it buzz, but no pulsating, and it draws less amps. When a ShurFlo fires up, all the lights flicker and you think the world is coming to an end!
I get mine from www.lewismarine.com
If you want to try a great portable water softener, which gives great showers and removes all that calcium that damages your polished aluminum- www.softwetspot.com