ARE THEIR OPTIONS ON THE LOCATION OF THE HIGH POINT IN A STEAM MAIN

geoprell

(This discussion is taken from "Burnham IN5 Steam Boiler Runs With An Empty Gauge Glass")
I have a new gas boiler installation (single pipe system). The steam Main is in a small basement with a ceiling height of six feet (6'). The original steam main was designed with the high point at the corner of a "L" shaped Main. The long leg is 29 feet, with 5 branches for 7 radiators that pitch toward the return. The short leg is 8 feet, with a single radiator and pitched back to the boiler.

HERE IS THE QUESTION?
The short leg of the Main (with a single radiator) in front of the boiler is 6 foot and pitches 2% back to the boiler (pitch is 1 3/8" in 6'). Their is also another 2 foot "L" above the boiler that pitches 3% back to the header (pitch is 3/4" in 2'). I am assuming that it was originally designed this way because their is not enough height for the high point to be above the boiler (not enough room to wrench pipe if it is pushed up against the joists and plaster board).

HERE IS MY THOUGHT
What is the difference between steam condensate flowing back to the boiler through the Main in this short length of Main and the condensate that flows back to the Main through the branches from radiators. They both experience the flow of steam away from the boiler and condensate returning to the boiler. The most important criteria should be to have enough pitch to move the condensate back to the boiler before steam is created again.
I am afraid that if this section of Main is raised, it will only be level, or at most, have just a slight pitch away from the boiler. Pitching this short section of Main back to the boiler seams to be the best solution as long as their is enough pitch, so a conflict between steam and condensate is not created.
I want to achieve the best performance, but I do not want to ask the contractor to rework a problem that maybe should be left alone.

SEE ATTACHED PHOTOS

WHATS YOUR THOUGHTS?

Jamie Hall

There really are only two rules: there must be a drip to a wet return at any low point, and there must be enough pitch so that the condensate can drain. Keeping in mind that counterflow (steam and water going in opposite directions) requires either a larger pipe or a lot more pitch -- or both -- than parallel flow. Check the tables in Lost Art for proper size and pitch for either one, based on EDR.

Level is never acceptable...

Steamhead

Are there any radiators connected to those two short runs?

nicholas bonham-carter

Are these pipes well insulated, which would reduce the amount of condensate from that initial short leg of pipe.
Probably putting on a drip from main to wet return would drain any condensate from that pipe quickly back to the boiler.—NBC

JohnNY

That first picture looks like it could be a counterflow main, though probably just a bad install, and I get nervous when I see unions on mains downstream of the system connections to the header. Also, your Hartford Loop is not good.
Here is the counterflow header piping arrangement preferred by Weil-McLain:

geoprell

REPLY:
Yes,their is a single radiator (EDR 40 sq. ft.) connection to a second floor radiator on the short side of the "L"(between elbow and union).The remainder of the "L" is unencumbered.
Yes, the pipes are insulated.

Hartford Loop:
My gas boiler is a Burnham IN5, looking at the installation piping diagram, I am not sure what is incorrect with the Hartford loop.
Please explain.

Counterflow Near Piping Of Main:
Would extending the Riser above the Header (even with the Main), then with elbows, bring it back down to the existing Header create a counterflow system for the Main near piping?
Sense the Header is the low point of the short "L" Main (Header has a 4% pitch toward equalizer), can the connection of the Equalizer off the Header be considered the "drip" wet return connection? Is the objective here, to keep the steam dry?

The Details:
The pitch for the short leg in front of the boiler is 2%, and the "L" over the boiler has a pitch of 3 %. The Header has a 4% pitch.

The EDR calculation for the radiator connected to this short leg that pitches back to the boiler is 40 sq. ft.

(The EDR calculation for the radiators connected to the long leg that pitches toward the return away from boiler is 260 sq. ft.)

The steam sq. st. of a Burnham IN5 boiler (IBR) is 358 sq. ft.

I could not find the chart diagram to determine pipe size and minimum pitch. Given the numbers listed, any recommendations for:
40 sq. ft. EDR (single radiator)
6' and 2' - short leg and "L" over boiler
2% and 3% pitch - short leg and "L" over boiler

Appreciate any advice.

Thanks,
George

geoprell

NEED ADVICE - PLEASE HELP

Is it possible that the 2" Main (6' and 2') with a 2% and 3% pitch is sufficient for a counterflow leg that has a 40 sq. ft. EDR radiator connection?
Also, is it possible that the current Header / Riser configuration is adequate if their is no knocking ?
Can I then assume that all the condensate is returning by way of the Equalizer and that the pitch is sufficient?

Appreciate any advice.

Thanks,
George

Neild5

What is the pressurtrol set to?

Fred

Is there any hammer at any of the points you are concerned about? The problem with one of your original thoughts is that condensate not only returns after a heating cycle has ended but also during a heating cycle. Enough condensate returning and falling into the header, with no drip somewhere in the main before the header, that drops into a wet return will cause hammer or some of that condensate to be carried back out into the system, with the steam, causing wet steam.

geoprell

Neild5 -
The cutout is 2 and the cut in is 1. I tried cutout 1.5 and cutin .75, but my boiler will turn off before the thermostat is satisfied (it of course turns on when the cutin calls for more pressure). Is this a good thing (it saves money I guess) ?

Fred -
No hammer, just trying to make sure that during the installation of my new boiler, that the contractor did everything that reasonably could be done, given the low ceiling height. The contractor did not change the pitch of the Main, this is the way it was.
The only sound / "noise" I hear is the sound of air/steam being pushed up to that radiator during the first 5-10 minutes (approximately), and what I would consider pipe expansion ( I believe the pipe rubs against wood framing somewhere, its a creaking sound).
How do I tell if their is "Wet Steam", what sound or effect would I hear or see?

Thanks for the advice.