1908 2-pipe steam

JK_3

We're going to work on a 2-pipe gravity return system from 1908 that serves a 20 unit 5 story apartment building in New Jersey. I believe it to be that type of system because of how it compares to other systems in Dans Lost Art book. I have a real good handle on 1-pipe. 2-pipe & vapor, not so much.

The radiators have 3/4" supply valves & 1/2" return 90's neither with orifises. The return part of the radiator has a concentric connection. There are no traps on the radiators or anywhere in the system. The supply & return risers are 2". Supply risers off the 4" main & the return riser dumps into an 1 1/4" dry return main. There are dry & wet returns. The building was coal heated until the 1950's when it was converted to oil. The end of the dry returns have Gorton # 1 vents installed into existing tees in the basement only. There is a check valve @ the end of one of the wet returns.

My first instinct is to add radiator traps and larger vents.

What do you think ?

JK_3

1908 2-pipe steam

I almost forgot to mention that the radiator valves where made by Marsh of Dunkirk NY. Not the Marsh from PA or the other one. I researched this to find out. I also know there's no orifises because I took the valve's & return 90's apart to look inside.

Steamhead

Did you look

inside those concentric radiator return bushings? There's a chance you might find water seals in them.



Most Vapor systems were installed with eccentric bushings on the radiator outlets. This was to make sure all the water drained out of the radiators. But there were some systems that incorporated water seals and tiny air vent holes in their return bushings. These appeared concentric from the outside.



If they're just open bushings, don't worry- that means the radiator valves probably have some sort of orificing capability built into them. You won't need traps. Keep the pressure LOW- that means a Vaporstat. Vent the heck out of the steam mains and watch how well it works.

Jamie Hall

I'd also be inclined

to wonder why the check valve is there... unless that particular return has a leak?

JK_3

coal

Another thing that I'd like to figure out is ,how was this system intended to operate on coal ?

Also for example on one part of the building, the top floor gets much hotter before the first floor. With steam following the path of least resistance, could we assume if those valves have orifises or there's tiny hole in the return bushing that perhaps they are no longer functioning ? Therefore adding traps could be one route to take.

I was also thinking that maybe a riser vent would be in order. What to you think ? 

JK_3

bushings

Do you have any pics of these water seal bushings ?