Wacky Steam Trap Configuration

justinh

Hi. My building is a 16 story building in lower Manhattan. We are setting about replacing all radiator steam traps throughout the building. We have a two pipe steam system designed and installed in the mid 1980s. Wondering if anyone has any idea what someone was thinking when configuring these two-trap set ups shown above. This configuration is found in a good handful of locations throughout the building. We are considering changing this configuration to a more standard setup as found in most places in our building. But wanted to see if there was some acceptable rationale for installing these two traps in one location. The image below shows a more typical setup found throughout with just one trap.



Any input is much appreciated. Thank you.

Jamie Hall

I can think of one reason, though it may not be the right one -- that big Nicholson will pass a lot more air than the little Stirling, and thus the fin tube to which it is attached will heat up a lot faster.

ratio

Someone did it that way for a reason. I'd think long and hard about why they did it that way. Like Jamie said, the first thing that pops into my mind is quicker venting—is there a reason why this (& the others) might need to heat faster than the others? Entrances, exterior walls, larger spaces, north facing, lots of glass? Step back and look at the whole picture and see if there's a common thread that ties them all together.

And, of course, maybe someone hacked them in in an attempt to fix a problem, or they had extras on the truck that they didn't want to send back. Ya never know!

EBEBRATT-Ed

The Nicholson will only act as an air vent. It should never see any water. According to what I saw on line they both appear to be standard thermostatic traps.

I see no need for two traps as long as the sterling is sized properly

Steamhead

Jamie Hall said:

I can think of one reason, though it may not be the right one -- that big Nicholson will pass a lot more air than the little Stirling, and thus the fin tube to which it is attached will heat up a lot faster.

You nailed it, Jamie. There is no other reason for installing the Nicholson that way. We've done the same thing.

I'd bet these are installed at the tops of risers or other far-flung locations in the system.

DanHolohan

Yes to what Jamie said.

the_donut

So why two traps instead of 1 larger trap or an air vent?

DanHolohan

One trap serves strictly as an air vent to the dry return and the main vent down the line. It makes the unit heat more quickly. It's an old-school trick, similar to using a crossover trap from the main to the dry return. It's sort of like adding a one-pipe steam vent to a two-pipe radiator, without having the problems that the vent would present.

justinh

Thanks all. Very helpful. Makes a lot of sense. And Steamhead is correct that these configurations are found in upper floors. Haven't found this below the 14th floor. Everyone's feedback is much appreciated!