Hi, I'm new to this forum so I apologise if I'm not adhering to etiquette!

I'm removing a radiator as I'm doing some decorating. I've turned off the locksheild valve and I have also set my Thermo valve (Drayton RT212) to the 0/decorators setting.

When I open the bleed valve I get a constant drip of water (maybe 6 drips per min). I've left it drip for quite some time but it doesn't seem to stop. Has anyone else found that it the bleed valve drips like this once the valves have been seemingly closed?

If I were to drain the radiator would I be able to plug the leaking valve?

"Dysanovic" wrote:

Hi, I'm new to this forum so I apologise if I'm not adhering to
etiquette!

I'm removing a radiator as I'm doing some decorating. I've turned off
the locksheild valve and I have also set my Thermo valve (Drayton
RT212) to the 0/decorators setting.

When I open the bleed valve I get a constant drip of water (maybe 6
drips per min). I've left it drip for quite some time but it doesn't
seem to stop. Has anyone else found that it the bleed valve drips like
this once the valves have been seemingly closed?

If I were to drain the radiator would I be able to plug the leaking
valve?
--
Dysanovic

I haven't had this with a radiator valve not shutting off completely but I
have known it with other water stop valves. You won't know whether it's the
TRV or the lockshield valve until you take the radiator off. You could
leave well alone, just put a bowl or tray under the valve during decorating
and put the rad back as soon as possible. If it's the lockshield you may
find that another slight turn will stop the drips. Or drain the system then
replace the leaking valve, refill, add inhibitor, bleed rads etcetera. I'm
not sure what you mean by plugging the leaking valve, unless you mean
blanking off the valve inlet/outlet by fitting a screw-on end cap. You could
do that if you can find an end cap to fit. Did you make a note of the
position of the lockshield valve before you turned it off?

Hi Codswallop,

Thanks for the reply. You are spot on, I got a spanner instead of a pair of pliers to make sure that the locksheild valve was shut and that appears to have done the trick. When I undo the bleed theres now a little bit of water escaping at first but then nothing, no drips! So now I'm going to drain the radiator.

Yes I made a note of where the locksheild valve was set to. To also make life a bit easy I used a perm. marker to mark one end of the valve, which will visually help when I need to set it back to its old position.

I'll let you know how the drainage/re-fitting of the rad goes!

Drained the radiator with no real problems. Took about 4 cat-litter trays until it was empty. Found that the locksheild valve was weeping ever so slightly so I tightened it a little more. Fingers crossed it'll stay shut :s

A question I have is when I have to put the rad back on, do you reckon I should put some PTFE tape around the male bit of the rad valve? I obviously don't know whether it is going to leak but this is probably a good precautionary measure?

In article , Dysanovic wrote:
A question I have is when I have to put the rad back on, do you reckon
I should put some PTFE tape around the male bit of the rad valve? I
obviously don't know whether it is going to leak but this is probably a
good precautionary measure?

The point of Teflon tape is to reduce the rotary torque you have
to put onto the fitting to get the necessary compressive (longitudinal)
force on the metal-to-metal sealing surface of the valve. The tape might
help you if you're finding the fitting still leaks after you torque it up
to the maximum permitted torque (you do use a torque wrench on the
fittings don't you? Didn't think so - I don't think the suppliers even
put torque figures on their datasheets. Maximum permitted torque is
therefore where your adjustable spanner slips once, starting to round the
nut. You don't want to your nuts round.)
In normal practice, getting Teflon tape slivers between the
surfaces of a metal-to-metal seal is a recipe for leaks. If the metal
surfaces are scratched, you might need to look at a joint sealing
compound, rubber seal, or something like that. Going down that road is
out of my experience for DIY and water - if you're plumbing analytical
hydrogen into a laboratory, I can give you some compound names. (NB :
Teflon tape is appropriate for root-filling of NPT threads, which seem to
be used for radiator taps. But only up to a couple of hundred PSI.)

Teflon tape is like WD-40 : for the job it's designed for, it's a
good tool ; but it's not designed as a cure-all, panacea, general
factotum, miracle-worker or bike repair kit.

--
Aidan
Aberdeen, Scotland
Written at Mon, 23 Oct 2006 10:46 +0100, but posted later.

Aidan,

Cheers for the very well written reply. As well as PTFE tape having a low co-efficient of friction (hence reducing the "the rotary torque you have
to put onto the fitting to get the necessary compressive (longitudinal)
force on the metal-to-metal sealing surface of the valve"), it is can also resist extreme temperatures and it's water tight.

I think the fact that it gives a water tight seal is why so many people use it as a quick fix!

In article , Dysanovic wrote:
I think the fact that it gives a water tight seal is why so many people
use it as a quick fix!

Like I said, I've not much experience of using Teflon tape on
water. I guess the hydrophobicity of the Teflon would help it to seal a
metal-to-metal surface against water.
For analytical gases (and I guess for fuel gases), it's worse than
a waste of time, and I can understand why amateurs are not permitted to
**** with domestic gas systems. The temptation to think "this material
makes pipes seal tight, for water, so I'll use it to seal the gas pipes
too" is obviously there. It can take a several attempts to beat the idea
of never using Teflon tape on gas seals out of novices in the workshop,
and some of those I wouldn't trust to plumb up a camping stove, let alone
a permanent installation.

--
Aidan
Aberdeen, Scotland
Written at Tue, 24 Oct 2006 09:18 +0100, but posted later.

wrote in message ...
On 24 Oct,
Aidan Karley .group
wrote:

In article , Dysanovic wrote:
I think the fact that it gives a water tight seal is why so many people
use it as a quick fix!

Like I said, I've not much experience of using Teflon tape on
water. I guess the hydrophobicity of the Teflon would help it to seal a
metal-to-metal surface against water.
For analytical gases (and I guess for fuel gases), it's worse than
a waste of time, and I can understand why amateurs are not permitted to
**** with domestic gas systems. The temptation to think "this material
makes pipes seal tight, for water, so I'll use it to seal the gas pipes
too" is obviously there. It can take a several attempts to beat the idea
of never using Teflon tape on gas seals out of novices in the workshop,
and some of those I wouldn't trust to plumb up a camping stove, let alone
a permanent installation.

There is a (thicker) PTFE tape available for gas use.


... easily identied as it's YELLOW! ...

--
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