Replacing faulty towel rail valve

TheGreenFrog

I have a leaking towel rail valve (picture attached).  It appears to be leaking from top of the valve so I am assuming it cannot be fixed, but am not sure.  If it needs replacing I am proposing to do the following and want to check that it is correct and/or I am not making work for myself:

1.  Drain the towel rail loop (there is a stopcock and a drain valve on both the outflow and return pipes (see picture of the return, the outflow is exactly the same).  To do that I close both stopcocks (already done to stop the leak), attach a hose to the drain valve and open the drain valve.  I then open the bleed valve on the towel rail (there are two towel rails attached to the loop so maybe I should open both).

2.  When towel rail loop drained I close the drain valve, take off the faulty towel rail valve and replace it.

3.  Pour inhibitor into the towel rail.  Close towel rail bleed valves, open stopcocks and fill system via fill loop. 

4.  Turn on boiler and test towel rail loop etc. 

ThisIsWeird

Is that the lockshield valve? What's on the other end?

You wanna just stop it leaking?

TheGreenFrog

ThisIsWeird said:

Is that the lockshield valve? What's on the other end?

You wanna just stop it leaking?

Yes that is the lockshield.  The other end is a standard non thermostatic valve (not that standard because they are 22mm 3/4 valves) .

I just want to stop the leak.  Tightening the gland nut did not do it so I assume I now need to either replace the valve or unscrew the gland nut and try ptfe or similar. But even unscrewing the gland nut requires drain down I think?

ThisIsWeird

TheGreenFrog said:

ThisIsWeird said:

Is that the lockshield valve? What's on the other end?

You wanna just stop it leaking?

Yes that is the lockshield.  The other end is a standard non thermostatic valve (not that standard because they are 22mm 3/4 valves) .

I just want to stop the leak.  Tightening the gland nut did not do it so I assume I now need to either replace the valve or unscrew the gland nut and try ptfe or similar. But even unscrewing the gland nut requires drain down I think?

Cool - you clearly understand what's going on.

No, you don't need to drain down :-)

Wire-brush the top of the spindle and gland nut to clean it up.

Note the position of the spindle - stick a paper flag on it and count the number of turns it takes to close down fully clockwise - turns and part-turns. Close it.

Close the other end.

If you want - not really necessary - bleed that towel rad to release the pressure inside it - only a wee trickle should come out. Close the bleed screw.

Undo the gland nut - that's the top nut only, not the round brass collar below it. No water - other than a few drops - should come out. Just in case the design is different to most*, undo the nut slowly and keep an eye out for leaks...

The actual valve mechanism - the screw-thread and rubber washer - should be contained within the lower part, so the valve should still be shut off, with no risk of leaks. The rad won't drain either, as it would need air to get inside it to replace the water. You should be totally safe against wetness :-)

But obvs have a towel around the pipe...

Clean the spindle further.

Not sure what the best solution to resealing the spindle is, but PTFE tape should do. I also like to give such moving plumbing objects a good smear of silicone grease - don't use normal grease.

Get a length of PTFE - a good foot at least, twizzle it to make it a 'rope', press one end down there, and lightly wind it around the spindle, pressing it down with a screwdriver or summat. Don't just have it tight against the spindle - nicely fill the whole circle. Repeat if needed - you want a good few mm of padded-down PTFE thickness by the sounds of it.

If you also have sili grease, then smear that on the spindle first, and even get a good smear down inside the recess. I'd even wipe some on the tape-rope as you squish it in. Oh, and some on the gland nut thread - which you've cleaned up too...

Replace the gland nut, do it up hand tight, and then whatever it needs to squish the PTFE - this will be a matter of judgement.

Open the LS to its original position, open the other valve, check for leaks. If it drips, give the gland a half-turn more.

Repeat as needed.

*Looking at your pic again, it does look different. Most gland nuts sit inside the main valve body, and screw down to compress either a rubber washer, or a sealing rope. But your nut looks as tho' it goes over the part below. I wonder if your design has a rubber washer immediately under that nut? If so, gently prise it up the spindle, check it, cover everything with sili grease, wind some PTFE around the spindle both under and above the washer, and replace. Also take a photo and measurements of the washer, as you can always get a replacement.

TheGreenFrog

@ThisIsWeird thank you for help.  I live in a remote place.  I would gladly pay my plumber to do the job but he is ill and finding a replacement far from easy.  

ThisIsWeird

You going to DIY it, then?

TheGreenFrog

ThisIsWeird said:

You going to DIY it, then?

Depends on how quickly plumber recovers (he’s been incapacitated for over a month) and how much household pressure I get to fix the towel rail!

TheGreenFrog

ThisIsWeird said:

TheGreenFrog sa

*Looking at your pic again, it does look different. Most gland nuts sit inside the main valve body, and screw down to compress either a rubber washer, or a sealing rope. But your nut looks as tho' it goes over the part below. I wonder if your design has a rubber washer immediately under that nut? If so, gently prise it up the spindle, check it, cover everything with sili grease, wind some PTFE around the spindle both under and above the washer, and replace. Also take a photo and measurements of the washer, as you can always get a replacement.

Spindle when pulled out has a couple of (seemingly non-replaceable) o rings which seem to be what is causing the leak.  I propse to wrap a bit of ptfe around the spindle and see if that does the job.



4.50 pm:  job done!

ThisIsWeird

Brilliant! Have to say, I haven't seen one like that before.

Nice job