Rad valve gland packing?

Hi all,

We are servicing Mums old CH system. It was a coal fired single pipe / gravity jobby but was modified a few years back (30?) to be a fully pumped system. with a wall mounted low capacity b/f boiler.

Today I tapped a 15mm draincock into one of the 1-1/4" brass elbows [1] and whilst the system was drained down and because most of the rad-valves were either showing signs of leaking or nearly impossible to turn (impossible for Mum to turn) we went round them today, removing, stripping, cleaning and re-fitting.

The only thing I'm not quite sure about is what to re-pack the glands with?

The seem to be filled with a string of some sort and most came out intact.

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of them are gate-valve design (as linked above and tend to be fitted at the tops of the rads) and the others are more like a stopcock but with a free rotating metal 'cone' instead of a rubber washer etc.

So, what to do about the gland packing. I've tried running the old stuff though some Boss White and it softens up a bit and I can carefully feed it back in (but can't get it all back in) and once the gland nut is nipped up it all feels much smoother and like it wouldn't leak, but is there a 'proper' solution please (and no, Mum doesn't want to replace the lot). ;-)

I used 'Plumbers Grease' on the actual screw threads (that's what they gave me in the merchants).

Cheers, T i m

[1] Whoever upgraded the boiler removed the ability to drain the system lower than the boiler return. ;-(
Reply to
T i m
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Ah, see the Leaking Radiator Valve thread of 19/9/12

In summary, you can repack with string, hemp, or PTFE (tape or string)

Here is one way:

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do a variation of that and simply wind 15 turns or so around the spindle with the tape roll held in such a way as the tape ends up bunched rather than laying flat. Then snap it off, and force it down into the gap with the gland nut. Nip it up a little bit so the tap still turns freely, and that should do it. (you may need to experiment with the right amount of tape for your glands - it will also vary depending on if you rake out the old packing or just leave it and add some more on top).

Reply to
John Rumm

(snip)

Gland packing (string) 99p per metre on Ebay.

Derekg

Reply to
DerekG

Hemp. I'd expect nylon to do better though, nylon twine's common and cheap.

NT

Reply to
meow2222

You can still get plumber's hemp on a roll. Or, use ptfe tape, twirled into a string and wound around the shaft. I also use, in conjunction with the above, a grey Italian jointing greasy non-setting putty. Never had a rebuilt one leak, unless the shaft is too far gone.

Reply to
Grimly Curmudgeon

You can buy valve stem packing at proper plumbers merchants. It's made of PTFE these days. It won't go hard like the old stuff. Don't put it in like a spring, you need separate little rings cut to length with the joints staggered. Don't be tempted to use PTFE tape either, it is quite unsuitable.

Reply to
harry

Cowboy tricks None of the above should be used, especially on valves frequently operated. Hemp. will score the valve stem. Once it is scored the packing wears out very quickly. PTFE tape squeezes out of the packing box.

Reply to
harry

Ah, sorry about that. I do normally have a quick look but I assumed people wouldn't do this sort of thing any more. I forgot this was uk.d-i-y. ;-)

Yup, I got that (and have stripped and re-done 4 of 7 valves so far) but as the local (old skool) plumbers merchant couldn't supply a 'new' replacement packing materiel (and he suggested I re-used the old as it was in good nick considering), that's what I started to do. However, preferring to do things 'right' if possible, I thought I'd ask here.

actual leak I guess or until you drained the system fully.

Understood.

After reading all the replies here I did a more specific Google and found quite a few people liking the 'Loctite 55'. This seems to be a PTFE 'cord' that is probably not far off what some PTFE tape might end up as once pushed inside the gland by the nut.

General thoughts though .....

These taps valves have been in use, potentially un-serviced for over

60 years and were obviously of good quality when they were made. Even to the point where the gland packing collar is separate from the tightening nut and you can adjust the nut over the top of the ferrule that covers most of the hardware when in place (and you don't even have to take the Bakelite knob off to do it). ;-)

Whatever was used for the packing hasn't marked any of the spindles

*at all* in 60 years.

Whatever was once the 'lube' in the 'string' (?) has just dried out and therefore the 'string' hardened and therefore making the spindle prone to leaking, or, if when tightened to prevent the leaking, made the spindle much harder to turn due to there being no 'give' in the packing.

So, ideally and especially if it didn't cost a lot (in time getting the right stuff or money) to replace what was there with some of the same, that would be ideal.

Now, in the real world Mum is 82 and we have loads of more important things to do (for here and ourselves), so as long as she can turn these things on and of (she's not 'frail as such' atm) and they don't leak then I'm guessing that will 'do' (even though it goes against my grain to some degree). (Possibly) 'Spoiling the ship for a hapenth of tar' as my Dad used to say. Doing it right won't take any longer than doing it nearly right, once you have the right materials. ;-)

So, in case I can easily find some suitable 'string', any idea what lubricant I should use on it? ie, Is Boss White going to stay flexible long enough? Silicone grease ... Plumbers Grease (or as I believe I saw mentioned somewhere, a waterproof grease (I have some suitable white grease for marine propeller shaft bearings that I got when I savaged an irreparable washing machine (sealed plastic tub) 5 years ago). ;-)

It's one of these things where it seems to be good gear in a great condition and part of the reason for that condition is that it was designed to be right (and last) in the first place.

So, what about a decent quality parcel string? I'm pretty sure the sort of 'hot' that a radiator gets isn't hot enough to bother any type of old skool / cotton(?) string?

Cheers and thanks again for all the replies and heads up guys. I could end up using any of them. ;-)

Cheers, T i m

Reply to
T i m

Thanks for that Derek but I can't seem to find anything that looks small enough. I'm guessing what is in there now (when you find a good bit) is between 2 and 3mm diameter?

Cheers, T i m

Reply to
T i m

I have horrible recollections of removing nylon fishing like and string from around my outboard motor proof shaft thrust bearings and seeing just how much damage something so soft (nylon) can do to something so hard (phosphor bronze). ;-(

Ok, these valve shafts won't be rotating so much or as fast but it is still a good demonstration of such things in practice.

Cheers, T i m

Reply to
T i m

Does it look like a long lock of a maidens hair (or horses tail), in which case I've still got some from back then?

Yeah, that looks like what that Loctite 55 is?

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I also use, in conjunction with the above, a grey Italian jointing

Yeah, the 'lube' is a good question, depending on what packing material you are using.

Like, if I was using a PTFE solution I don't think I'd lube it at all (or the water would be the lube).

If it were hemp or string I think it would want to lubricate the packing to shaft interface and seal between the 'fibres' of the packing. It also ideally wants to remain flexible but not was-away-able but not rot the material.

Even the old string packs back in ok ish, it's just that it's obviously a bit hard in places and doesn't pack down as well as it did when it was new / fresh.

Cheers, T i m

Reply to
T i m

I (thought I) used a proper plumbers merchants (and they do seem to come up with everything I ask about, no matter how old (within reason of course).

Ok.

So that's Loctite 55 then?

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T i m

Reply to
T i m

Fuck off, Harry. I've used both successfully for many years and never had one leak. Your experience of hospital steam valves doesn't bear directly on CH valves.

Reply to
Grimly Curmudgeon

I was having a general Google and it's interesting when you read up on the packing as used with something like a marine propeller shaft (where some water leakage is *required* to provide lubrication and stop the gland overheating) versus something like these rad valves where there is little movement and you don't want them leaking at all.

(It is there where I have seen reference to cutting 'rings' rather than use a spiral wrap as the packing material is quite a large section.)

Again, reading about I've also seen wool mentioned as a substitute for the proper stuff. So, I'm wondering what properties are required where they might suggest wool over say parcel or gardening string?

Undoing a couple of the valves I cleaned and re-packed yesterday, it seems the original packing material does seem to pack down pretty hard, so much so that you can slide it out like a metal sleeve. ;-)

I'm going to try a few different ways (I now have some Loctite 55 as well) and will keep a note of what I've used where and see how they compare over time.

Even if one solution doesn't work very well it won't be so difficult to replace the failed material with the valve in place.

Cheers, T i m

Reply to
T i m

That particular vid was a tad kack handed, however he does do some interesting things - with a rather "warts and all" production method.

There should be no need to drain for work on a top gland if the tap itself still shuts off ok. They normally only leak when the tap is "on".

Yup, cord is probably easier for this task, but ordinary tape works as well... (I normally go for tape since I have copious reels of it and no cord - which makes the decision making process easy ;-)

[snip]

and if it lasts another 60 years that will save doing it again in a hurry ;-0

Boss white tends to hardern IME... So a grease would be better. Not sure it matters much what sort in this application since there are no rubbers or plastics to degrade, and you won't be drinking from it.

A string twisted out of some traditional hemp would probably work well.

or all at once, that should do it!

Reply to
John Rumm

All those words and not a hint of the "proper" solution (well harry's version anyway).

(I wonder if he realises that many of the original ones were packed with hemp and grease by the manufacturers)

Reply to
John Rumm

Yup - mid brown like fine dry hair...

Reply to
John Rumm

I have experience with virtually every type of valve. This is the way it should be done. Apprentices learn this in the first week.

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Reply to
harry

Valve stems and motor shafts/propellor shafts need to be treated quite differently. If the packing is fitted to a revolving shaft, such as a water pump, a small amount of water has to be permitted to escape to lubricate the shaft. New packing is fitted but not tightened down hard. The pump is run and the gland nut/bolts tightened until about one drop of water escapes ever thirty seconds or so. As the packing "beds in" it has to be tightened, but always there must be the small amount of water leaking out to lubricate the shaft.

Failure to do this results in the shaft overheating and being scored and then no seal can be made.

Reply to
harry

Complete bollocks from begining to end.

Reply to
harry

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