Rubber caps on radiator valves?

bipbap

We have a single pipe steam system and as part of a renovation we had to remove 3 ground floor radiators.

They were diaconnected after the valve which was closed off as best it could but still looks to be leaking steam out.

I went to the plumbing supply and the guy says there is no cap made for that junction . To cap it right I’d need to remove the valve handle part as well.
One suggestion was a rubber cap with one of those metal bands that tighten around it. He wasn’t sure how long it would hold up but it’s prob better than running the system as it is and 3 leaky valves spouting steam.

It will probably be 2 months before the radiators go back.
Will the the rubber caps do the job? Any other ideas short of removing all the valves?
Thank you!

bipbap

I should also mention there are 2 radiators on each line above the removed radiators serving the 2nd and 3rd floor apartments.

KC_Jones

I have used a block of wood and a cushioned c-clamp. You want rubber or plastic pads on the clamp so you don't damage the valve.

Wood swells when wet, so even if it doesn't seal immediately it will in short order.

A long time ago on steam ships they used to use wood plugs in boiler tubes to stop a boiler leak (water tube boilers).

acwagner

I assume your valves are old and the original valve disc has rotted away long ago. You could get some EPDM rubber sheet, and cut it to fit in the valve so it seals. I've seen that work.

bipbap

OP here, what about using galvanized caps on these spots?
See photos.
Im confused because the plumbing supply shop didn’t suggest a cap for this spot but these would seem to work. Unless there is a reason not to cap them in this manner.
See photos, thanks!

KC_Jones

The threads on the valve are union threads not pipe threads, that cap won't work. There isn't anything I can think of that would screw onto those threads other than the radiator that it belongs to.

bipbap

KC- I just grabbed a 1 1/4” one from Lowe’s and it seems to fit well. See photo.
Is that strange?
Just like you said, the plumbing guys told me there was no metal cap for it but this seems to fit well.

KC_Jones

The valve has straight threads, the cap are tapered threads. It might screw on (which I would say is random), but it won't seal.

Gsmith

The best temporary solution is the wood blocks and cushioned c-clamps suggested by @KC_Jones earlier. Not much I can think of will likely work. Even rubber pipe caps like Fernco style secured with radiator type hose clamps will not likelyseal when the system steam pressure comes up to provide steam to the floors above.

Grallert

You'll find out if that galvi cap works, It shouldn't because the threads are different. At least I always thought they were different. As long as it fits and the threads aren't buggered. I have used a rubber cap with and a hose clamp with great success. As long as it's tight the steam wont move.

bipbap

The galvanized cap seems to screw on surprisingly well and tighten up nice.
Is the other option something like this photo?

bipbap

Either way, either of these options are better than doing nothing and the whole valve leaking lots of steam for next couple months right?

ethicalpaul

> @bipbap said:
> KC- I just grabbed a 1 1/4” one from Lowe’s and it seems to fit well. See photo.
> Is that strange?
> Just like you said, the plumbing guys told me there was no metal cap for it but this seems to fit well.

I think it's strange, but I’ve seen stranger. My 1-1/4 definitely don’t fit npt threads but your valve manufacturer might have done things strangely. If it works, it works.

bipbap

Also on a related note, how bad is it for the overall system to have 4 radiators (out of 19 total) disconnected and capped like this for a couple months?
I assume this is what you’d call oversizing your boiler?

Fred

It will make the boiler over-sized by another 20 or so percent (assuming the disconnected radiators are of average size to the remaining ones. It won't hurt much, other than some short cycling and maybe some imbalance on the heating of the house. Do all 4 radiators need to be removed at the same time? Do they all have to be disconnected for a full two months?

Boiler Talk

I removed a valve and it was unbelievably difficult. The house is about 100 years old.

Fred

Boiler Talk said:

I removed a valve and it was unbelievably difficult. The house is about 100 years old.

They can be a nightmare to get off! Don't throw it away expecting to use a new one. Rebuild it if need be. They usually just need packing around the valve stem. If you use a new valve, they come in matched sets and the spud, in the radiator will also have to be replaced. That can be even more difficult.

Boiler Talk

Unfortunately that ship has sailed. The valve is gone, but not the radiator. Someone may have problem in the future, but not me. I do wish I kept it though.

bipbap

Yep that cap leaked.
Guess I’ll try that clamp and wood method that was suggested.

bipbap

Is this the setup you suggested?
See photo...

KC_Jones

That's exactly what I've done for remodeling. For me it worked like a charm. Like I said if it leaks slightly it will seal up from the wood swelling in short order.

bipbap

I am thankful for your great idea.
I am thankful my radiatorless pipes are no longer spouting steam.
I am thankful for my steam heat on this freezing day, though I reserve the right to curse it out in the future.
Happy Thanksgiving, all!