2-pipe Steam- no traps

Joe Blanks

Came across a 2-pipe system today that was a little unusual to me. No traps anywhere. Each rad's return comes down into a dry return in basement, and there is an air vent at the end of the return main. This return main ties into a tee at the end of the steam main. This end of the return has a check valve before it ties into the end of the steam main. The 2 furthest rads (2nd floor) each have an air vent on the radiator. I noticed in 'The Book' that Dan says the only way to not use traps is to drip every rad, main and riser into the wet return. Is it acceptable to use this check valve? Looks like the original install...

DanHolohan

Probably don't need the check valve.

But I've seen some older jobs where the Dead Man used them like this. Can't hurt.



There are probably orifices in either the radiator supply valves or the return fitting. Got pics of those?



Thanks for sharing!

Joe Blanks

valves pics

Thanks for the reply Dan! Here is one rad I took a photo of. Didn't think to get a good shot of the return fitting. I saw that in your book too (orifice in valve) and just brushed by it...thinking nah, I don't have those.



You bring up another great point- I noticed that on 2 or 3 of the radiators another plumber replaced the valves. If in fact these DO have the orifices, what could happen with those newer valves that I'm sure don't have the orifices. Are these valves still available?



Thanks again,

DanHolohan

I believe those valves have orifices.

You can get orifices to fit in standard valves from Tunstall.