Water Hammer has burst my coupling

[muggles]

Are you sure the shower you purchased was approved for use on high-pressure systems? If it was low-pressure only, or required some restrictors that you missed out to convert it to HP operation, this could be the cause of the hammer

 

[iwaters]

Are you sure the shower you purchased was approved for use on high-pressure systems? If it was low-pressure only, or required some restrictors that you missed out to convert it to HP operation, this could be the cause of the hammer

The instructions said it is suitable for high and low pressure systems and for unvented hot water systems, combis, and ordinary cylinders.

It mentioned fitting a flow reducer for Type 2 (?) instalations but it didn't say they had to be fitted for high pressure systems. These were little things that looked like filters which go in the hose from the mixer to shower head. Maybe they are required?

 

[muggles]

Almost certainly they were required, yes

 

[iwaters]

It's fixed!

I had to cut a massive hole through the plaster board on the stairs. I added some noggins and cliped the pipes to them and then fitted a Sioux Cheif mini-rester. No more hammer!

I tried fitting a flow reducer which Anglian water sent me (7.6 l/min) but it made the shower rubbish. I checked the box the mixer came in a found a 12 l/min reducer which came with it. Seems to reduce the water a bit without making it rubbish.

Thanks for all the suggestions.

 

[theprinceofdarkness]

Very interesting, I would not have touched the shower. I looked up the Sioux web site to read how the arrester worked and even they don't understand properly how water hammer originates. They talk about a quick shutting of a water cock causes an pulse of high pressure which causes the pipes to knock - correct, this a "bang" not a hammer. What causes hammer is started by a valve going off quickly but the high pressure pulse then causes the "valve" to open, the pressure drops, the pipes straighten, the valve closes the pipes bend. . .
It is usually associated with a ball cock because you actually can get waves in the tank which accentuate the bouncing up and down of the ball cock "valve".
Reducing the pipe pressure by turning on almost anything can stop hammer.
About 6 months ago I had water hammer in a system that had run under many different conditions for about 9 years, three times in an hour I took apart the ball cock it all seemed to be OK, perhaps its action was sticky but by taking it apart I disturbed something. Anyway looked like new, put it all back. Your right! no more hammer, or at least not until that grain of grit gets into its pivot.
Frank

 

[bernardbeemer]

Very interesting, I would not have touched the shower.

?? What would you have done then? Your description of water hammer is all very interesting but of no use at all in this situation.
The OP already stated that the system is a sealed system so has no tank fed supply hence no ball valve. And you can hardly expect to turn on a tap or other system just to relieve the pressure!

I think the OP was absolutely right to tackle the shower and by fitting the mini rester the problem is sorted. Congrats to him.

 

[iwaters]

As it should be obvious I'm not a plumber but as I understand it the hammer was caused by the thermostatic valve in the shower open and closing quiuckly whilst it find the correct temperature when it turns on.

At the end of the day whether it was the right thing or not it cost me about £20 in parts and took me an afternoon and now it is fixed and working perfectly.

 

[theprinceofdarkness]

If the shower was a sealed system, where does the water come out of?
Frank