dishwasher makes pipes rumble

[bvisconti]

Lately (last few months) when we run the dishwasher, during the first cycle (and a few times in the complete cycle) the pipes in our house will rumble REALLY LOUD - like a jackhammer for about 3 minutes each time.

If I turn on the water in the sink, the noise will stop. Once I turn the water off again, the noise starts up.

Before I call a plumber, does anyone know what this is called? (water hammer, maybe?)

And is there anything I can try before calling a plumber?

Any help would be GREATLY APPRECIATED!

Thanks.

[Patriotic]

Before each use of the dishwasher, try running the hot (or hot and cold at the same time) water from the nearest sink for 30 seconds. What I suspect is air build-up in the pipes when water is not actually flowing (in use). When hot water sits idle, the hydrogen in the H2O sometimes comes out of solution becoming hydrogen gas under pressure. If left long enough (typically a month or more) enough gas can build up to actually cause an explosion. Even more likely, water may be draining back to your water heater, causing a slight "air block" in the pipe. When you turn on the dishwasher, the water displaces the pipe suddenly and violently, causing the pipe to rattle or slam until the pressure equalizes (typically a few seconds).

[Mark Weese]

if you can't get rid of it, try adding a home made muffler to the system...

its basically a tee'd waterline about 6 inches long that is capped on the end... it gives the water supply a sort of a buffer to push against as the pressure comes into play. the pressure of the water pushes against the air in the 6 inch tube, and eliminates the rumble/rattle you hear.

and please check the obvious, make sure your pipes arn't touching one another.