Water governor failure

[Handsome Jack]

Yesterday arrived home from holiday to hear a strange thrumming noise under the breakfast room floor, with signs of damp. Lifted the floorboard and found the mains water supply pipe, in which was fitted an ugly round metal object labelled Dereve Water Governor. This thing had a little bleed hole in the top from which water was squirting upwards at high speed, soaking the floorboards and joists.

On consulting Google it appears that the thing has an internal diaphragm that has probably split, hence the jet of water gradually destroying my house.

OK, things fail, and usually they can be fixed or replaced. But why would someone design a piece of equipment that is bound, eventually, to fail in such a catastrophic manner?

[Josh Nack]

Because it costs more to do it better.

[tabbypurr]

because they want you to tell everyone and drive them out of business.

[Brian Gaff]

Yes indeed, I think we have forgotten long term testing as most stuff if it lasts five years may last a lot longer but I suppose if you were going to fit such a thing inside a nuclear reactor you would bloody well life test it, but for domestic use, nah, nobody bothers any more, its like washing machine hoses that go hard and split. I do feel however that a failure mode should not be to flood ones house without some kind of way to stop it! Brian

[Brian Gaff]

You cynic. Whatever the pros and cons of the original post. I can think of lots of devices where failure modes are not considered and which if they happen can be very damaging or dangerous. Brian

[Handsome Jack]

Brian Gaff posted

That's really the point of my OP. What other examples are there? I couldn't easily think of any in the household context.

[The Natural Philosopher]

Well. I just replaced the 18 year old fan in a downstairs toilet by removing half the ceiling and refitting platerboard, reskimming and repaining.

That should see me out. . Thers a 12V transformer buried in a wall as well. That hasnt failed after 18 years

Thers a whole lot of mains cable buried in walls along with cat V cxable, and of course plumbing. That lot hasnt failed ither.

In fact there is insulation buried in the walls., That hasn't failed too.

And underfloor pipes in te screed.

In short the answer to your question is that sometimes the likelihood of failure is so low and the cost of fixing it only moderate, that its not worth naking easy access.

Bit like changing the timing belt on some cars. There you are at 100,000 miles/10 years faced with £1000 to change the cambelt. A process that requires so much car dimsnantling that you might as well change ALL the other belts and the water pump at the same time, whether they need it or not...:-)

Oh for the days of vast engine bays...

[John Rumm]

I just played that game in reverse - the water pump was leaking, so since that involved removal of lots of stuff including the cam belt (from which it is driven), There was no point in them not doing that and all the other belts in the vicinity while they were at it.

Daylight rubbery you might call it ;-)

I had enough trouble just getting my arm in there with a camera to try and work out what was leaking!

[tabbypurr]

if single realistic faults cause danger then they're not fit for sale, at least for electrical goods. IME though people often fail to appreciate many of the protection mechanisms that are used (in electrical products).

NT

[newshound]

This is what mechanics are for :-)

[newshound]

I should say that I am lucky, not only because I can now easily afford to pay someone, but also because my mechanic is even more nerdy and obsessive than me.

[harry]

In industrial situations there is a pressure relief valve fitted with the outlet going somewhere safe. I assume there's none fitted to save money. Most water PRVs are piston operated (ie no diaphragm) But prone to sticking. Esp. in hard water areas.

[John Rumm]

In spite of my usual MO of DIYing pretty much anything, I don't do cars generally.

However I did want to know roughly what was leaking so I could assess the probability of unexpected failure, since the car was booked in a few days hence and I needed to go places.

If it was a leaking rad or hose, then I would not have risked it since the possibility of total failure would have been high. However since it looked like it was just a to occasional drip from the pump that was landing on the hot exhaust manifold, I figured it would limp on ok for a couple of shortish journeys.

[John Rumm]

They are not usually fitted to save money in domestic situations either. They are normally there to either reduce water hammer and pipe noise, plus make life a bit easier for taps, or sometimes to provide a pressure balance for a shower etc.

[newshound]

I'd say pressure relief valves are almost always fitted to prevent overpressure, and often with some sort of "safe" outlet. Water hammer etc. is normally dealt with using something like an accumulator.

This failed item is a pressure regulator, used where mains pressure is (or can be) high to make life easier for all the various domestic valves and taps.

[John Rumm]

Note I am talking about a Pressure Reduction/Regulation Valve, not a relief valve. Apologies for the confusion - I had not noticed harry had wandered off at a tangent as usual!

i.e. as in the bottom right of :

yup.

[newshound]

:-)

Knitted copper bagpipes! I love it!