Water hammer (new washer-dryer)

[Jimk]

Indeed!

[Jimk]

Its Roger's approach to logic....;-)

[Jimk]

Would a "dead leg" be any easier to create? Also are these solutions advisable on a feed to a kitchen? Drinking water etc?

[Adam Funk]

The new washer-dryer causes fairly loud water hammer every few minutes when drying (I haven't any noticed noise when washing, but it probably only cuts on and off a couple of times over the whole programme).

I've seen water hammer suppressors that fit between the appliance hose & the connector:

but I don't have room for one of those under the kitchen sink, especially since I think it has to be installed pointing up.

There's also the freestanding kind:

which says "single-appliance", but I would have room to fit that to the cold water supply running through the crawl space under the dining room to the kitchen, & only one appliance is causing hammer. That one says 1/2" BSP, so I guess the installation method is to cut a gap of the right size into the water pipe & fit a tee with a 1/2" BSP pointing up --- is that right?

I'm also thinking of trying some more "improvised" measures first, such as wrapping the pipe in rubber (old bike inner tube) & clamping around that to a joist --- is that realistically likely to make a difference? (The pipes below floor level are already covered with insulation & expanding foam.)

Thanks.

[John]

Could one of your appliance hoses be a little too elastic?

[Brian Gaff (Sofa 2)]

Wee would there be hammer when its drying, surely you might expect it when wetting!

Brian

[Andy Burns]

condenser dryer

[Fredxx]

I would have thought quite the opposite.

[John]

Fredxx [e-mail] wrote in news:r5gfaq$k3a$ [e-mail]:

No - a soft pipe acts as a rebound.. I notice at home if I leave my garden gose attached - but turned off at the nozzle, hammer is very much a problem.

[Adam Funk]

Yes. (I probably should have clarified that to start with, but all the washer-dryers that I've seen use condensers to the washer drain rather than a big air vent.)

[Roger Hayter]

Does the washer drain go into a standpipe or direct into the waste system? The former is usually more satisfactory.

[NY]

Is the main advantage of condenser driers that they don't need to vent a lot of hot air to the outside, or is there any other advantage? I find that they do not do such a good job: the clothes are often very hot but still nowhere near dry at the end of a long drying cycle, and they are also very creased.

The best driers I used were laundrette-style ones at my university hall of residence, which used gas burners rather than electric elements to heat the air, and left clothes dry and yet not creased.

[Tim+]

I suspect that?s a washer/dryer issue rather than a condenser dryer issue. Tumble dryer drums are normally a lot larger than washing machine drums to allow plenty of air to circulate. Not possible with a washer dryer so you can?t effectively dry a full washer load.

More to do with the size of the drum and air flow than the heat source.

Tim

[Tim+]

Worth checking to see if your cold water system might have an air filled dead leg somewhere.

We fitted a surestop valve once but every time it was actuated it caused an almighty bang through the pipework. I was quite worried that it would push apart pipe fittings such was its strength.

Turned out we had a redundant cold feed in the loft to an old shower that must have the accumulated air. Removing it cured the hammer.

Tim

[#Paul]

The drums are smaller than most ordinary tumble driers I am familiar with, so you cannot dry as much washing at a time - you really do have to avoid over-filling them. I find my condenser drier useful (we have no space for a separate one), but mainly to finish off drying laundry that has mostly-dried outside or in a room with a running dehumidifier. But it does work fine on small-enough loads.

#Paul

[Adam Funk]

It used to go into a standpipe. Then we had the kitchen renovated & the same washer-dryer went into a combined sink trap & waste manifold under the sink. Then we replaced the washer-dryer (still going into the combined waste) & the water hammer started. But I don't see what the output of the appliance has to do with water hammer in the supply pipes.

[Adam Funk]

That's interesting. There is a dead leg under the kitchen floor (the appliances used to be on the other side), but the old washer-dryer didn't cause water hammer after the renovation. But from what I've read on the www, adding a pipe with air in it is supposed to be a way to *reduce* water hammer (the air cushion absorbs the sudden pressure changes).

[Tim+]

It can work both ways depending on resonance I believe. Certainly the dead leg was the cause of our troubles.

Tim

[John]

Spot on - It can cause a "bounce effect"

[John]

Is the "Condenser" water cooled?