Steam radiator valve: funtion question

Luv'nsteam

In working on my system, I have added four radiators. Actually, I have added two now and created now-capped take-offs for two more in the future, after construction.



My question is this, on a few of the old valves I disassembled for rebuilding (still looking for seals), there is a small hole in the gasket and metal that holds it, that seems to allow pressure to escape? And in looking for a new valve for one of the new rads, the local supply house said the steam radiator valves are different from hot-water valves because of this hole.



Does anyone know the truth about this? What is the reason for the hole and is the hole needed? I suppose what I really want to know is, what will happen if I install a valve with no hole, like a hot water radiator valve?



Thanks,



Mike

Jamie Hall

Not sure about the hole...

but I'd get a valve made for steam every time -- hot water isn't anywhere near as hot, usually, and I'd be a little wary of what the seals and seats were made of in a hot water valve.

Hap_Hazzard

Are you talking about orificing valves?

Is your system one-pipe or two?



I don't know much about two-pipe steam, but I read this post the other day-- http://www.heatinghelp.com/forum-thread/140629/Old-radiators-valves --and your description jogged my memory.

Luv'nsteam

Valves with orifices

My system is one-pipe steam. Originally, it was a Train vapor-vacuum system and maybe with coal? When we bought the house, the boiler was an oil-fired Fitzgibbons, 400 series, all vacuum lines were MIA and the only reason I know it was a Train is because the mercury filled air vent thingy was still in the basement. There is a picture of it in TLAOSH on page 257. All radiator air vents were replaced by someone else to Hoffman adjustable vents. I already purchased 1 1/4" radiator supply valves for steam heat from Grainger and these do not have the orifice. The one from the local supply house did have a small hole and a brass seal, but it was also reduced to a much greater amount where the seal and seat meet, much more than then original valves and more so than the new valves. I did not like this reduction, so I returned it. For clarity, this reduced area is where the steam and counter-flowing condensate pass through and, I need a valve for 1" pipe.



Jamie, I agree about the materials and temps they are rated for. Thanks for pointing that out, as I had not thought about it.



Hap_Hazzard, thanks for the link, however, it does not apply to my system.



Thank you,



Mike