What are we looking at?

Chuck_17

Can you see the photo?

This is in a church at the opposite end from the boiler room. The lower pipe on the right is the steam around the west side. The pipe above is the condensate on that side.
The lower pipe on the left must be condensate back to the boiler around the east side. It must drop below the floor (due to a doorway - I didn't check in the boiler room).
What are:
Trap/vent off top of the higher (right) condensate?
Large black object?
Connection between the end of the upper condensate and the piping below?

nicholas bonham-carter

Looks like a Dunham return trap. I would put a bigger Gorton #2 vent on it. There are details here on the Dunham system of vacuum heating-a Cadillac of steam systems.--NBC

Steamhead

Not a "return trap"- an air trap. Basically it's a housing with a float in it to close the air vent opening if water backs up into it. If this is the only such device in the system, it's the only place where air can escape as the steam comes up. So yes, that bullet-shaped vent on the standpipe is way too small. A Gorton #2 is the right choice here.

I also see a crossover trap- that's the radiator trap piped between the end of the steam main and the dry (overhead) return line. To the right is a shutoff valve sitting on top of the steam main that goes to a radiator someplace on the other side of the wall- possibly the radiator trap that's just barely visible below the air trap is the return from this radiator.

Condensate (water) from the steam main goes thru the Hoffman float-and-thermostatic trap in the drip line. Like the radiator traps, this unit allows air and water to pass but closes when steam reaches it. We do not want steam getting into the return lines. I'd be willing to bet the return line that exits at the left was installed later- the original may have been much lower which would have not needed the F&T trap.

So what happens here is the steam does not get past this point, the air is vented from the air trap, and the condensate drains back to the boiler room.