Leaking steam pipe suddenly stopped leaking?

bipbap

We had a leak coming down into our 1st floor apartment near one of the risers going up to the floor above. It was hard to tell if it was coming from the riser or the radiator sitting next to it. The guy who lives up above says he never saw any water in his place near the radiator valve or anything or any trace of water in his place..
It was a pretty decent size leak, so we just turned off that upstairs radiator since the heating season was pretty much over with the plan to address it this season.

Well we never addressed it and the guy upstairs turned the radiator back on this season and now it's not leaking anymore. The plumber was going to come back for a look, but he says if the leak is gone, then no need to mess around with it. It just seems strange that a steady leak "fixed" itself without us doing anything and so I'm nervous it will come back since we didn't really fix anything.

The only other thing is that we had pressure issues last season where the boiler was going up to nearly 5 psi. We've since added a vaporstat and a bunch of main vents so the pressure isn't supposed to go above .75psi this season.

Could it have been the high pressure that was causing the leak, maybe stressing out some of the joints?
Any other reason a steady leak would disappear?
This is a 1-pipe steam system.
Let me know what you think, Steam Detectives.

Fred

It's very possible that a joint or valve leaked at 5 PSI and reducing the pressure resolved the problem. You'll just have to watch it for a while.

Kahooli

that and small leaks can rust shut (low pressure seal).

mikeg2015

Yup.

I have evidence of leaking valve stems and 1 radiator that leaks at the push nipple, and one fitting on the boiler leaks above 5oz. But after changing main vents, skimming turning on 3 radiators that we’re turned off and balancing the system, pressure is under 2oz. No Leaks.

If it was hot water, I’d have a lot of work to do.

Jamie Hall

My guess is that it was the valve packing leaking. The combination of reducing the pressure and turning the valve may have allowed the packing to reseat.

But I wouldn't guarantee it...

bipbap

Jamie, if it is the valve packing, is the solution to repack it or to replace the valve?
And if it was a leak there, wouldn't the guy upstairs see some water in his apartment?

Jamie Hall

bipbap said:

Jamie, if it is the valve packing, is the solution to repack it or to replace the valve?
And if it was a leak there, wouldn't the guy upstairs see some water in his apartment?

Repack it. It's not hard to do. Replacement is a bear.

And on the second -- not necessarily. The leak could just follow along down the pipe and appear in your place instead.

Neild5

We had a radiator leak a lot when the system was set to 7 psi, since adding main vents, downfiring and setting pressuretrol to .5 psi no leak in 2 years.