High Water Pressure and Washing Machine leak

[NeilPalfreyman]

I've recently put a new washing machine into a new house which has quite high water pressure and despite being done up "hand tight" the inlet has started to leak after a few days.

When the washing machine feed comes on and shuts off I can see the pipe and hose jerk quite violently.

I have tightened up the connection gently using mole grips, trying to avoid over tightening and it's no longer leaking but I'm very worried that the pressure and "jerking" will cause it to leak again at either end. For info the flexible feed pipe and washers are new and high quality (tool station.)

Any suggestions? Do I need a pressure reducing or limiting valve of some kind?

 

[Burnerman]

Toolstations. 64117 shock arrestor could help you here, but do keep an eye on things for a while.
John

 

[NeilPalfreyman]

Cheers, John! Do they just go inline between the valve and hose? Do you (or anyone else on the forum) have any good or bad experiences of using them?

I must confess that the cynic in me is reluctant to replace one potential point of failure (ie the connection between the shut-off valve and hose) with two (ie shut-off valve to arrester / arrester to hose.) Am I being paranoid?

 

[Burnerman]

Hi Neil, yes these things screw onto the valve, then the hose screws onto the arrestor.
Being metal, the arrestor can be well tightened onto the valve......it's the plastic hose that is the weakest link here.
All I can say is that it did work for one application of mine, where the washing machine would be leak free for months......and then, the small pool developed. Water shock is definitely an issue here!
John

 

[NeilPalfreyman]

Thanks again, John - you've convinced me!

Do these things have a "maximum operating pressure" and should I check the mains pressure first and consider a pressure reducer/limiter at the mains inlet if necessary?

(This probably all sounds paranoid but the leak we've had was pretty bad and will have cost me a few hundred quid in replacement floor covering and kickboards by the time I'm through.)

 

[Burnerman]

It's a sealed vessel Neil so no need to worry about the pressure of the water....nothing will burst.
John

 

[NeilPalfreyman]

I've just been to tool station and bought one. Somewhat surprisingly the packaging recommends installing it directly onto the washing machine outlet, not between the hose and the shut off valve.

Although this is counter-intuitive I guess it makes sense since the washing machine shutting off is what generates the pressure wave. The manufacturer claims that installing it there will protect everything "downstream" from the washing machine.

The downside of this is no metal/metal connection to tighten with some "welly."

Any thoughts? Where did you install yours, John?

 

[Burnerman]

I've installed mine in exactly the same position......direct onto the valve.
So long as it's near to the machine, it should do what's necessary......all it will do is to dampen the shock wave caused by the valve shutting off.
I'd also use one on the dishwasher if necessary.
Do let's know how you find it.....water hammer is a massive issue for many people.
John

 

[NeilPalfreyman]

I fitted it (directly onto the machine inlet) this afternoon, John, and it was immediately obvious from a test wash cycle that things are different. The noise of the internal valve opening and closing is much less audible and not as "harsh" (if that makes sense) and the pipe is hardly moving at all.

However, I had to tighten the metal fitting on the mini-rester much harder than I would have ideally liked to get a water tight seal on the washing machine and similarly had to tighten the hose onto the mini-rester much tighter than I would have liked. But all three joints survived a full wash with not a trace of water

 

[Burnerman]

Just to confirm, Neil, I fitted mine to the water off / on valve at the wall, and then connected the fill hose to that......sorry if I sounded confusing!
The main thing is no leaks of course, and you are right, the fill 'bump' is significantly damped.
I would imagine the arrestor consists of a split chamber - water on one side, then a rubber diaphragm followed by air on the other side......similar to an expansion vessel on a heating system.
John

 

[NeilPalfreyman]

An update on this. Although the arester seems to be doing it's job fine, I can't get the hose to stop dripping where it joins the arester.

I'm thinking about fitting one of these at the mains water inlet now:

http://www.screwfix.com/p/honeywell...arch-_-SearchRec-_-Area3&_requestid=32556#_=p

as well as replacing hose/washers.

May be overkill, but this is starting to annoy me!