Steam Main trap

RemlingerHTCL

Hello everyone, I’ve been servicing a two pipe steam system that has this trap on the supply in the horizontal section before it goes up to the air handler. It’s by passing so much steam my boiler feed receiver is so hot I can touch it. It sounds like someone left a garden hose sillcock wide open. So I’m assuming it’s bad. My questions are, 1. What is the purpose of it being on the supply so close to the boiler? My guess was that it is for any steam that condenses in the riser that falls back that way it doesn’t pool up and create water hammer on the next cycle. 2. The numbers are pretty much nonexistent, how do I know what size to replace it with?

Intplm.

Yeah, the sounds and reactions as you describe are what require a rebuild or replacement.
I am willing to bet that steam is discharging from a vent to the atmosphere from a condensate return tank too.
That's a Dunham Busch steam trap. You can make the size from a pipe size.
Since you cannot see any numbers describing the trap fully. I would contact Dunham Bush directly.
They might be under a different name now.
If you like, there is another company that works with most if not all steam traps by the name of TP Tunstall.
Look into them as well.

Jamie Hall

Your supposition as to what it is supposed to do is probably correct. Whether it is doing it or not is another question, and the fact that it is passing steam means that whatever good it might be doing is completely ruined.

I'm not totally sure that it is necessary -- it depends a lot on the pressures you are running and how those pipes are connected -- but since you also mention a condensate receiver, it almost certainly is.

Easy to fix. Well, as these things go. I have a suspicion that getting it apart may be a bit of a chore...

Steamhead

It's called a "drip" trap in this application, draining condensate from the main as you surmised. Rebuild or replace it and the problem will be solved.

Dunham is now MEPCO, and you should also be able to get parts from Barnes & Jones or Tunstall.

RemlingerHTCL

Thank you all, I figured I was on the right track but wanted to be sure.

EBEBRATT-Ed

That is a header or end of the main drip trap.

Believe it or not the correct way to size this trap is by calculating not the steam but the WEIGHT of the pipe valves and fittings in the steam line upstream of that trap. Then you figure the amount of water being condensed by heating those pipes valves and fittings up to steam temperature.

I have done this and find that in almost every system a 3/4" F&T (any brand) will take cere of this load