Dishwasher & Plumbing Experts

[Pickled Piper]

I have a Bosch built in dishwasher. Ever since it was installed I have found that it causes the household plumbing to rattle when the internal valve in the dishwasher turns off. i have tried to identify any loose or badly fixed pipes from the point the cold water mains enter the house right up to the dishwasher. There really isn't anything obvious. There is nothing else that causes the same rattle, closing the kitchen tap suddenly will not do it, nor will the washing machine cause it.

I am assuming that it is the internal valve in the dishwasher that is closing suddenly inducing the rattle. Is there anything I can do to prevent this? I have tried partly closing the valve to the dishwasher feed in order to reduce the water pressure but this has not helped. Is there anything else I can do? Perhaps fit some sort of regulator?

Thanks in advance for any help.

pp

[barney123]

Mine does the same - you can stop it by reducing the pressure into the house at the stop-cock, wherever that is.

Or you could put in a pressure reducing valve....

[benjdr]

Sounds like water hammer?
http://www.google.co.uk/search?hl=en&q=water+h...

[Pickled Piper]

benjdr said:

Sounds like water hammer?
http://www.google.co.uk/search?hl=en&q=water+h...

Yes that's it exactly. Thanks. Now to work out how best to alleviate it.

pp

[V10Mike]

From an engineering point of view, you need a small pressure accumulator in the mains line before the dishwasher valve.

DIY approach:

A 30cm (12in) length of vertical pipe should be added to the existing pipework via a T-joint as close to the source of the hammer as possible.
The other end of this pipe is capped off, and it is filled with air which acts as a shock absorber.
Unfortunately, this air will eventually dissolve in the water such that hammer will return unless the whole system is drained periodically to allow air back in.

Or, to do it properly: http://www.shockguard.co.uk/

[Pickled Piper]

Thanks. Shock arrestor on order.

pp