Questions about radiator shutoff valve.

trouts2

My shutoff valve leaks steam. I can hear it sputtering but there is no water dripping anywhere. The radiator heats up. The leak does not seem to affect any other radiators as they all heat up.

The leak is where the rod for the shutoff knob goes down into the valve. There is a nut there and I guess it would have packing or some sort of O ring to prevent steam
getting out past the shutoff rod. I’ll attach a picture if I can.

Does the shutoff knob and rod have to come out? I can’t put in an O ring unless it comes out. I could use some sort of thread with another substance if there is such a thing.

What do I have to do to stop the leak and what is needed? It seems like I would just unscrew the nut and put something under the nut. ?

mattmia2

you can first try tightening the nut, if there is still enough packing to compress in the packing gland. If that doesn't stop it (go easy on tightening it, you could break the nut if you really crank on it), unscrew the nut and slide it up the shaft, put a couple little pieces of string packing in it and tighten the nut back down. You may need to do this a few times to get enough packing in it. Be careful about spreading the old packing around if some of it comes out because sometimes the old packing contains or is asbestos.

You can take the screw or nut out of the handle and remove the handle if you need more room. Not a terrible idea to clean the stem where the packing and nut seal to it with some scotchbrite either.

trouts2

mattmia2,
OK, thank you for the response. I nervous about mucking with anything old because of what you mentioned, a nut cracking or I strip threads & etc. If something screws up it will likely be a few weeks before I can get someone here.
I unscrewed the nut a few turns without difficulty then snugged it back down to see if that would seal the leak. I doubt it. I’ll get some plumbers thread and pack it of the leak does not stop.

I guess from what you said the handle and rod into the valve will just unscrew out. Is that correct? There is no other parts would be affected if I take out the handle and rod to get the screw and take of the nut? I could then scotchbrite the rod, clean out the nut and repack it.

There is a thread call pecking thread made of teflon. Is that ok to use under the nut. The stuff I'm used to seems to be just common cotton thread. I think many turns of flat teflon thread seal would probably work also.

mattmia2

trouts2 said:

I guess from what you said the handle and rod into the valve will just unscrew out. Is that correct? There is no other parts would be affected if I take out the handle and rod to get the screw and take of the nut? I could then scotchbrite the rod, clean out the nut and repack it.

No, if you wanted to remove the whole stem you would have to unscrew the bonnet and thread the stem out through the other side and that is usually a lot harder to turn than the packing nut.

If you remove the handle by removing its screw you should be able to get enough access to the stem to clean it up and shove some more packing in there.

trouts2 said:

There is a thread call pecking thread made of teflon. Is that ok to use under the nut. The stuff I'm used to seems to be just common cotton thread. I think many turns of flat teflon thread seal would probably work also.

Teflon or conventional graphite string packing should work fine. You could use a bunch of wraps of teflon tape too.

trouts2

There was some partial success.
The pictures show the top of the nut lifted up as I turned the wrench. I do a lot
of fixup on things and never had a nut break like that.
I put 3 wraps of Teflon on the threads and two wraps of 3/32 graphite on the rod for the handle. [ Is the rod what you called the “stem”?]

I tightened up the nut and resistance came early and I thought that due to the 3 wraps of Teflon tape. From then on the resistance from the nut back to the wrench
was not a lot but fairly steady. I kept turning as it did not seem to bottom out, no big resistance. There was nothing to indicate the nut was properly closed down.
I noticed the top of the nut was lifted and stopped turning the nut. I work on lots of stuff and never had a nut do this before. The nut top must have been compromised before as the pressure I had on the wrench was not enough to destroy a nut top.

It looks like the top was a press fit part onto the nut. It may have ripped
the connection but it is weird as it is a smooth arc. Whatever, the top of the nut is damaged. When I looked again there was melted graphite oozing out from the
lifted section of the nut top.

All the house radiators heated. There was no leak from the nut area. When it gets colder and the heat on longer the packing will probably ooze out so the nut will have to be replaced.

How can I get the nut off? Will it lift off the rod if I remove the on/off handle?
It seems like it should.

I think I will not have to remove the rod which I think you are calling the stem.
What is the bonnet?

“No, if you wanted to remove the whole stem you would have to unscrew the bonnet and thread the stem out through the other side”

mattmia2

It isn't uncommon for brass to get brittle like that especially when there has been a leak for a long time.

The "rod" is the stem.

If you remove the handle you should be able to get the nut off but you would have to find one for that specific valve, they aren't standardized. You may be able to find a washer that will fit inside there to hold the packing in, maybe find a washer that fits inside and drill a hole in it the size of the stem. You would have to dig the packing out first so that the washer sits at the top of the packing nut.

That very much looks like asbestos packing so probably wet it down when working with it and be careful not to get it airborne or spread it around.

The teflon on the threads doesn't do anything, the fiber or teflon compressed inside around the stem is what makes the seal.

The bonnet is that piece just below the packing nut that the the packing nut threads on to, it has a wide flat surface that makes a metal to metal seal to the rest of the valve body. You would need 2 wrenches, one to hold the valve and either a big crescent wrench or socket to try to turn the bonnet itself. Probably not worth it in this case.

This is more of an industrial version but it shows the parts of a globe valve:
https://instrumentationtools.com/what-is-a-globe-valve/

delcrossv

At this point, I'd just put in a new valve. They're about $30 for an import and maybe 15 minutes to install if you reuse the union from the old one.

nicholas bonham-carter

The valve and union, called the spud are a matched pair, and may not seal, if mismatched. In addition, the height of the replacement valve outlet may be different from the old. Try to find a washer which can fit inside the nut, and snugly around the stem.
Keeping your steam pressure down to the ideal 2 ounces will help as well.—NBC

mattmia2

BTW, that will probably seal as long as you don't turn the valve, it needs that part of the nut mostly to keep the stem turning in the valve body from pulling the packing out with it.

THEPUMPDOCTOR

Any ideas on how to buy a replacement valve stem nut? I have a 1-1/4" brass angle radiator shut-off valve and I too split the nut by having "strength like Bull and brain like Pidgeon"! I called supply house etc. and of course, they can sell me a whole new valve but I just need a few valve stem nuts. Most of the valves in my house are the same it seems. Any help is much appreciated.
Thanks, Andrew

JUGHNE

For the cracked bonnet nut, I have loosened it, put some graphite packing in and started the nut on. Then put a very small hose clamp on the nut and ever so gently tighten the nut. The packing will evenly get wet and swell to seal.

It is a Red Green solution that does not involve duct tape.