leaking drain cock - bad choice in the first place?

[jkn]

Hi All
some years ago I fitted a drain cock, like this:

https://4f5b8d3b6b0bf8e595f4-4a9207d71aad635e548035542d638275.ssl.cf3.rackcdn.com/6921.gif

in the feed to the kitchen cold water tap. IIRC this was to allow draining
of the final part of the circuit (which includes an outside tap) in case we were away, etc.

In recent months this has been leaking ... enough to fill a container placed below in 4-5 days.

I have tried tightening the screw, and replacing the washer, to no avail. I have
also tried removing the washer assembly and cleaning out the inside of the cock
with steel wool, in case there was something caught inside. No joy, it still
drips.

I will replace the fitting if I have to, but it's soldered in and difficult to
get at, so it will be a pain to do. A couple of questions:

- is there anything else I might try to fix this?
- is this the right kind of fitting to use in a 'high pressure' situation such
as this? I normally see these on radiator tails, and wondered after the event
if I should have used a different kind of fitting.

Thanks
Jon N

[Andrew Gabriel]

In article <2a8cb769-6489-455c...@googlegroups.com>,

I think that's quite normal - I've used them in this situation.
There really isn't any good solution for a valve that works reliably
when operated once every ~25 years.

Are you sure the leak is from the drain cock, and not running down
the pipe from somewhere higher up?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

[Dave W]

"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:o4ham1$h7j$1...@dont-email.me...

I expect particles in the water have worn grooves in the seating for the
washer. If it's difficult to get at you won't be able to grind it flat.
--
Dave W

[GB]

On 03/01/2017 22:17, jkn wrote:

> I have tried tightening the screw, and replacing the washer, to no avail. I have
> also tried removing the washer assembly and cleaning out the inside of the cock
> with steel wool, in case there was something caught inside. No joy, it still
> drips.

I drained a hot water cylinder, changed an immersion heater, and
refilled it. Everything was fine except for the f***ing drain cock. So,
I drained it down again and replaced the washer. That worked, fortunately.

You've done everything right, so I can only suggest that you try a
different washer before changing the fitting.

If you never actually drain the system that way, could you get some of
that "dries under water" sealant and block up the hole the hose is
supposed to connect to? Plus some Boss Green on the screw thread.

[harry]

That drain cock is intended for quite low pressures, ie central heating systems.


You need to remember that the washer has to seal on both sides, water gets down the central spindle.
So the moving metal disk the washer rests on has to be perfectly smooth as well as the valve seating (on the valve body)in order to make a perfect seal.

Some valve washers have writing embossed on them, if so, the writing should face the valve seat for best seal. (Not the moving disc part).

[rick]

I have several of same type on my heating system .. all failed to seal
after draining down system.
Just changing washers did not work on 2 of them, so went to local
Plumbers Merchants bought new ones .. and just swapped over the screw in
unit .....

On 03/01/2017 22:17, jkn wrote:

[tabb...@gmail.com]

On Tuesday, 3 January 2017 22:17:48 UTC, jkn wrote:

As mentioned make sure the water isn't coming from elsewhere, eg from where it's soldered on. Then use something like epoxy to block it. You can always add a self cutting one if you haven't got the space to solder.


NT