Steam talk....

Timco

I should mention this system used to have a collection pit, now steel over the pit and a box. Can a water seal be re-created? In my area, really no end of main f&t's used, all mains just return to boiler room as wet returns.

Tim

Timco

Lately I have seen several steam systems, 2-pipe, with no end of main trap. The main just makes a u-turn and heads back to boiler room, and becomes a wet return. This has a vent in the boiler room that vents (through a trap) into the dry return, which ends up connecting to the wet return / water seal. Question is, on a job where there is no end of main trap, and the boiler is now using a condensate collection box (no water seal) what is the best way to trap the steam before it goes into the box? Bucket trap? I have access to boiler room piping, but not end of main.

Tim

Timco

Dumb question? Can a water seal be re-created? I have steam shooting out of a main vent from a collection box, and want to trap it but no end of main trap...

Tim

Steamhead (in transit)

Put an F&T trap

in the drip where it comes down from the steam main. In many cases all you need is a 3/4" F&T. You need a trap for each drip from a steam main, but not for dry return drips since the radiators already have traps. Do NOT try to get away with just one trap at the condensate tank, this will cause major problems.

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Timco

Followed main, and no drip. Just main and makes a tight u-turn at end of run, and heads back to boiler room. One riser comes off of it along it's way back. Then vents into dry return through a trap, then dry returns drain into it where it drops to below the waterline. Dry return has a vent in boiler room and at very farthest point from boiler room. No other vents or main traps or drips. I can imagine how the main is supposed to let condensate run back, and there is a lot, so a f&t would not let condensate get back fast enough. I thought of a p trap like piping arangement so water would push past the trap by weight, but it would have to stop steam pressure as well.

Thanks Frank,

Tim

Steamhead (in transit)

Oh, OK

the drip from the steam main routes both air and condensate thru a trap into the dry return. THAT's your end-of-main trap. Webster systems used this setup rather frequently.

Since this is a 2-pipe system, the most condensate this trap would handle is when the system is warming up the steam main. A 3/4" F&T trap is usually enough to handle all but the biggest mains, but check the manufacturer's sizing info to be sure.

Sounds to me like the system has all the traps it needs. So either the pressure is too high, causing flash steam, or there's a trap leaking steam into the dry return. The solutions are obvious.

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Timco

When I said through a trap, I should have clarified. Sorry. As the main comes back to the boiler room, still pitched towards boiler, (mains pitch down from boiler) just before it dives and becomes wet return, a 1/2" line comes up 2-3' off the main and over to the higher dry returns to vent the very end of main, and this vent is trapped with a standard radiator trap. There is no other trap or drip on the main, it just turns into the wet return. just traps at rads, on single air vent from end of main (goes up to ceiling) and vents on far point of dry return and dry return in boiler room. Steam just keeps cruising past where it would have made a water seal and into the box now. Pressure is at 1.5psi. All traps in building new, (22) builds pressure great except for end of main just dumping steam into box.

Tim

Timco

I would think this could be tied into hartford loop or equalizer so condensate can be reused not pumped, and steam pressure does not escape and no trap is needed.

Steamhead (in transit)

Put your F&T trap

where the "end of main (is) just dumping steam into box".

The F&T should go on the vertical pipe coming down from the steam main, not on the horizontal going to the condensate tank ("box").

And I wonder if that condensate tank is really needed.....

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