Main vent problem?

dk · January 2004

Hi, there,

Now I am confused, about the main vent, I saw my house have two 2" pipes strain up to the roof with one hoffman angle #40 air vent connected each, one is in the bathroom, one is in the dinningroom, questions:

1. What are they?
2. how to tell which one is for short main supply, and which
one is for long main supply(assuming they are main vent).
3. If I like to replace them with Gortan vent, which one
should I chose, #2? or?

Thank you all in advance.

dk

Steamhead · December 2003

Are these

just 2-inch risers with no radiators connected to them?

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dk · December 2003

Steaamhead,

No radiators connected to them,,, just the pipes(risers) go to the roof, the #40 is about 1 foot away from the roof.

dk

scrook_2 · December 2003

Hoffmann #40

is just a non adjustable radiator vent. As the pipe is just capped and not connected to any radiators, it is just a long radiator itself. Do they heat up quick enough to heat the rooms they pass through? are there also radiators in the D.R. and bath?

If not, perhaps Gorton D radiator vents would work, a #1 or a #2 would need a reducing reducing ell and a 1/8" nipple to fit the main vent to the tapping in the pipe.

What do you have for main vents in the cellar at the end of the horizontal mains? This would be a good place for Gorton #1's or #2's if the current vents aren't up to snuff, so the steam gets to the inlets of the radiators, and to the riser pipes you describe, fast.

Steamhead · December 2003

Also

how long are those steam mains, and what pipe size?

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dk · December 2003

Steamhead,

The main supply pipes are about 40' in the front, and 20 ft in the rear, 3" diam size, and I took a look there were no main vents at each side that people described 15'' around the end ell?( also a questions now, is it possible that I can add them in the future?). Thanks.

dk

Steamhead · December 2003

You can use

two Gorton #1 or Hoffman #75 vents on the long main, and just one on the short one. BTW, was that 3-inches the outside diameter of the pipe?

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dk · December 2003

main vents problem

Steamhead,

Thanks for the reply, the main pipe outside diam is 3", but the two risers diam are 2", and how could I tell which is suppose to be long and short? because the two risers just wnet through from the first floor one in the bathroom and one is dinning room, should I assum the one in bathroom is short one? since it is more close to the rear end? Thank you!

dk

dk · December 2003

#2 and #1

Scrook,

Thanks, I also got two #D gorton vents now last weekend, and I would see how it goes, I like to use the #2 on long main( Steamhead suggeted use 2 #1 on the main, but there is just one port there) and #1 on short if it is ok. Thank you all.

dk

dk · December 2003

Put 2 Gorton # D on the risers

I have replaced 2 #40 hoffman with 2 #D gorton vents at the risers pipe which are branch up from the main supply( both about five feet from the boiler) all the way to roof, I noticed that the two riser pipes gets hot fastter, and the all radiators heat up much faster too( the burning cycle around 13- 20 min shorter), I would like to ask if I still need to add main vents on the two main supply? is it the main vents must vertical up or can they branch out? Thanks in advance!

Steamhead · December 2003

Are those risers

fed from the very ends of the steam mains?

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dk · December 2003

About in the middle

Thoses risers fed from the middle, the one from long main supply is about 5-6 feet away from the boiler then branch out to the wall and sraight up through to roof without radiators, the one from short pretty much the same is about 8 feet away from the boiler. By the way, I remesuare the pipes, I believe the mains are 2 1/4" and the the risers go to the roof are 1 3/4". Thank you very much.

Tom_22 · December 2003

Hoffman #75 got huge vent holes and cost $$$.

two Gorton #1 or Hoffman #75 vents on the long main, and just one on the short one.

Hello:

I looked at one of those Hoffman 75 Vents at the plumbing supply the other day. Dang, those puppies have three or four huge vent holes in them. I got a Home Depot special deluxe main air vent (the only one they sell: it has a 3/4" connection and costs about $7.00) on my basement main (2" x 60') and the vent hole on that looks about the size of a number 6 radiator vent.

The 75 is so much more huge than what I have on there now it scares me. How much faster will such a vent make the steam come down my main? Would two of those bad boys be recommended for me also? They were charging $57.00 each for them also. Not cheap, no siree. Whats the approximate payback time on saved fuel, or maybe you factor in reduced wear and tear on the boiler and whole system????

How about the Hoffman 4A main vent. How much 2" pipe are they good to handle? I forgot to look at one of those and ask the price.

Happy New Year to all and the best,
Jake

Tom_22 · January 2004

Gorton #1 Looks Nowhere Near the Size of A Hoffman 75

>> two Gorton #1 or Hoffman #75 vents on the long

Hi, Is a Gorton #1 about equal in venting rate to a Hoffman 75? I doubt it by looking at them. The H75 is about three times as big overall with about 5 to 10 times the orifice area. An H75 also costs five times as much as a Gorton #1.

Tom

Tom_22 · January 2004

A Gorton #2 is equal in venting to about three #1s

>>>>like to use the #2 on long main( Steamhead) suggeted use 2 #1 on the main, but there is just one port there and #1 on short if it is ok.

++++++
...I think... I have to find my notes. You can manifold the tap on the long main to put in two #1s.

Tom

PS: Does anyone know the venting rate of the Gortons in cubic inches/min. at .5 psi?

Steamhead · January 2004

Unscrew the cap

from the top of a #75 and you will see that the orifice underneath is similar to the Gorton #1.

If you blow thru them, you will feel the same thing.

Then try a Gorton #2. You'll see why I like this vent so much.

The Hoffman #4A is so small that I only use it on very short mains... about 15 feet or so of 2-inch pipe, or less. I remove many more of these vents than I install. I suppose some techs install them because they're relatively cheap, but when I see one at the end of a 60-foot main it makes me wonder why they bothered with it? Sure, a Gorton #2 costs more but in this case it's the right part for the job.

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Steamhead · January 2004

Yes you can

I do that all the time to install two main vents when there's only one tee. Works fine.

The Gorton #2 actually equals four Gorton #1 or Hoffman #75 vents.
I don't have the CIM ratings at 1/2 PSI. But I find that with proper venting, you can fill a steam main with steam at 2 ounces or less. Steam at this miniscule pressure is very gentle and very quick.

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Main vent problem?

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