dripping taps


Postby Nearlyman » Mon Feb 21, 2011 10:37 pm

Having surfed through the Forum looking for tips on curing this "common" problem without hitting the mark I turned to the Projects section. Here I did gain some insight and learned about the re-seating tool. Whilst this project would have solved all my issues - at one visit - at any previous time, i.e. other properties I've lived in over the past 45 years, it has left me, on this occasion, none the wiser.
The taps in question are 'conventional' Pillar taps and pretty much look the same as the example used in the Projects section: the video shows a tap with a rather different style of capstan, but otherwise conforms, generally, to the 'norm'.
The taps in my property - built c.Autumn 2004 - are made by Bristan: model ref 1901. But a number of differences are evident.
Not only do they drip (they have tended to drip for over five years): When I say "they" I mean ALL of the taps, including the bath shower tap - this amounts to 8 taps on all. For the record they were all brand new in late 2004.
In addition, some became very stiff to turn: releasing the gland nut only slightly improved this, but water was inclined to seep past the nut after this was done so, with some difficulty, a very fine balance was achieved whence this was almost eliminated.
Dripping from the spout was the main issue, however, and in spite of my 40 plus years as an engineer covering toolmaking, development engineering in extreme hydraulics, industrial instruments as well as aerospace design engineering I remain baffled.

One particular thing did strike me - very early on - was that the 'shut-off' characteristics of these taps match none in my experience; they shut off rather in the manner of a light switch, i.e. virtually instantaneously; there is no give what-so-ever in the washer; it is as if the washers were made of steel.That is, from closed to fully open takes a full half turn, but when closing the valve, flow doesn't cease completely until the washer is driven very hard against the valve seat and the capstan "stalls".

Living as I do on a development of several houses built by a sole developer during 2001-2006 and on which, by good fortune, five of my relatives also live, I was able to do some "live" testing in order to make comparisons. With a few exception my house was among very last houses on the development to be commissioned. Interestingly, although the same make and model number the shut-off charcterstics of the taps in the older property c. 2003 were just as I could have predicted: soft, progressive and drip free. I tried another daughter's property [an even earlier build] c.2001, and these taps were the same - soft, progressive and not dripping and never have dripped, which is what I'd expect for a house of such young age (as houses go).
Moreover, the taps on these earlier built properties were - because of this soft closure - noticeably more comfortable to use: in my case a conscious effort is required to ensure the water has indeed stopped flowing - for an engineer this is completely unsatisfactory.

So what is happening here? Changing the washers [on all the taps] was aborted after the valve in the first tap proved so unbelievably obstinate to remove. Some cosmetic damage to the chrome plating resulted and a 15 min.(max) job took over two hours; during which time the entire water supply to the house was cut-off. Had I anticipated such stubbornness I might have used a totally different approach: one that would have enabled me to restore the water supply to the rest of the house within minutes (on a temporary basis) whilst working on the "offending" tap(s). Unlike the legal requirement, which exists in Germany, to fit an isolation valve to every pipe to individual taps in residential properties there are none at all in my property: the only exceptions being the (3) lavatory cisterns.

Having eventually removed the valve, inspection of the valve seat revealed no evidence of damage: after a little over 5 years light use I wouldn't reasonably expect to see any. The house has been occupied only by myself and my wife, both pensioners, from new, and we place far less demand on these facilities than might be the case with a young family having the 'obligatory' 2.4 children.

A new washer "solved" the drip problem - sort of, but did nothing to reduce the inherent stiffness in the spindle. Yet another difference then became apparent: the washer removed from the original build was measurably smaller in diameter; in spite of having been in service for over five years. I measured this at around 1mm less than the replacement (standard 1/2") washer. I did enquire at one of the largest plumbing outlets on the Island if there was a (smaller) metric version, but they were unable to confirm this - I'd hate to think that they "couldn't be bothered" to look, but the manner of service I received was noticeably lacking in enthusiasm. Perhaps they considered I was being too picky? The fact of the matter is the replacement washer is not performing too well: the "hard stop" phenomenon is, pretty much, still there! That is, I have not been able to replicate the desired soft, progresive "feel" I found with the taps in my daughters' properties.

I would feel well up to completely stripping these taps, i.e. do a full dismantle because I am confident - with my skills background - I could improve their performance. However, there is a final piece to this puzzle: in spite of looking for tell tale splits or other clues as to how the valve was assembled, I cannot for the life of me find a way into the valve in order to dismantle it completely - whatever it is holding the spindle into the body is either very well hidden or the valve has been so designed as to prevent stripping down for servicing, i.e. built-in obsolescence. That would be fine if I'd been using them for at least 10 years, but when they "fail" to perform satisfactorily after such a short life I tend to think otherwise.

For the record I did attempt to develop a telephone dialogue with Bristan, but it resolved nothing - I was unable to reach anyone with sufficient design knowledge (or authority?) to enable me to find a solution.They did send me some replacement valve assemblies, but surprise surprise they were for a different model tap entirely and hence, no use to me - I gave up on Bristans at this point!

Can anyone throw any light on the above issues please?

Nearlyman
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Postby stoneyboy » Tue Feb 22, 2011 8:46 pm

Nearlyman,
If you live in a hard water area the problem will be scale forming on the internal brass threads. Suggest you get in touch with bristan and see if they can supply tap revivers to suit your taps.
end
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Postby alavapint » Tue Feb 22, 2011 9:52 pm

Can I first of all congratulate you on the most precisely detailed question I have ever seen on a forum.

Bristan taps ... I know exactly what you mean... I have done battle with them many times.
The characteristics you describe are common. The head of the tap is always difficult to undo.

Remove the capstan and the shroud. I'm afraid it's a big pair of soft jawed grips to grab the spout, and a ring spanner to undo the head assy.of the tap.
When you have the head assy out, wind the spindle out until most of the thread is exposed. Clean the thread if needed, and apply some petroleum jelly. Then work the spindle in and out until it works freely.

Washers are not all the same ... the humble 1/2'' washer comes in a great variety of thicknes's. They vary in diameter and also in density.
Some soft and some hard.
I buy my washers loose from a hardware store where I can check them individually.
For he Bristan tap I always fit a soft washer.

If the face of the tap needs cutting back then do it... but really speaking, there's not a lot more to do. .. I doubt if the gland will need re-packing as they are not old taps.
Good luck..!
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Postby Nearlyman » Fri Feb 25, 2011 3:23 pm

To Alavapint and Stoneyman

Many thanks for the positive responses.
Will now face the prospect of improving these wayward taps from a better informed advantage. The washer info is intriguing though - will take great care to heed your advices here.
Happily, for the record, we do not live in a hard water region - a lot of our water is from the hills and is almost spring-like in quality. It is, however, highly corrosive to brass: such fittings are required to be resistant and more like marine brass.

Nearlyman
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