How to choose the right mains air vent replacement

JamesC in Stamford CT

Hello, we just purchased a 1930s house that has a 1930s oil-fired one-pipe steam system. The one room in which I want the most heat does not get any, because (I think I figured out) that the radiator in that room it is the last radiator in a long horizontal run and there is a mains air vent in the cellar just below the room at the end of this run that does not hiss. Even though the radiator above hisses a little, the thermostat stops calling for heat before the steam gets that far. So I want to replace the mains air vent, pictured here, to see if that solves the problem. The outside male thread measures about 1", so I think I figured out that I have a 3/4" NPT male vent. Can anyone help me select which vent to use? (i.e. brand, model #). The boiler is about 8 years old, specs as follows:

Peerless ECT-03-120 SPT

Gross output 144,000 BTU/HR water

142,000 BTU/HR steam

446 Net sf steam

IBR 107,000 BTU/HR steam

Rating 125,000 BTU/HR

Max Steam 15 psi

Max water 30 psi

Max water temp 250 degrees F

Min relief valve cap 144 lb/hr

Thanks!

Rod

Main Vents

Hi-  You'll probably want a Gorton # 2  which are available from Pex Supply on the internet.

Gorton makes 2 main vents - The Gorton #1 and the Gorton #2 . (The #2 has 3 times the venting capacity of the #1.)   The Gorton # 2  connect is 1/2 MPT so you'll also need a 3/4 MPT x 1/2 FPT bushing to attach it to the pipe.  With main vents you can under vent but can't over vent.  Start out with one Gorton #2 and see how that does. If necessary you can add more venting by increasing the number of main vents.

- Rod

nicholas bonham-carter

counterflow system? vent

you seem to have a counter-flow system, with the main vent at the end of the main. is there only 1 main?

if so, you could spend some time calculating what make and model, would be the correct vent, based on the length and diameter of the main pipe, or you could just get the biggest main vent available [gorton #2], and start saving right away. you will not have wasted any money in my opinion, because by over-sizing, you will keep the escape air velocity very low, thus speeding up the arrival of steam. if there is a second main, then you must put on the same amount of venting, otherwise, there will be a noticeable difference in the speed of the 2 mains. try pexsupply.com for the vent.--nbc

JamesC in Stamford CT

How to choose the right mains air vent replacement

Thank you! I will order this, and see how it works.



btw, nicholas, you asked if this is counterflow -- I did not really know. Although we lived for 20 years in a NYC apartment with one-pipe steam, we were renters so I didn't concern myself with how it worked.



Now we own a home with steam, I have to learn these things. So, I googled, and it seems per Hoffman's Basic Steam Heating Systems guidebook, with all it's pretty diagrams (I found it at http://www.bellgossett.com/literature/files/7250.pdf ) I can say now confidently that I have a one-pipe parallel flow wet return with a Hartford loop. Gee, I can almost convince myself I know this stuff.



Well, it's kinda a wet return -- the return line starts out higher than the water level (water level when cold), and ends up below the water level as it gets closer to the boiler.



Anyway, thanks for all your suggestions!



Regards,

James

Johnny13

One hisses a little, the other not at all.

Apparently my mains are barely functioning. They can be seen in the picture attached. The picture is a bit misleading, and the ceiling space for the one on the right is about 1" clear. The other has a bit more, but not much. I have a 2 flat building with 10 radiators (originally 13, and hopefully again some day). I can't quite get my head around how big a Gorton #2 is. I seem to remember that you need to have a main vent a certain distance above the main, and I believe the only way I could make a #2 work would be to connect it directly to the pipe. Should I try that, or get some #1s and start an antler? I think they are significantly smaller right?

JamesC in Stamford CT

As for what type of bushing?

OK, so I was about to order the G2 Gorton and the bushing. But Seems there are many different types of metals for pipe fittings -- some made of cast iron, some of maleable iron, brass, etc. Also, pipe threads are maybe different.



I found these two bushings below -- can anyone tell me if either is the right one for the G2 to be connected to my 3/4" NTP female main (per picture in first post, which has a 3/4" NTP male main vent).



http://www.pexsupply.com/Ward-FBHE3-4x1-2-3-4-x-1-2-Black-Hexagon-Bushing-746000-p



http://www.pexsupply.com/Jinan-J-BLB-0705-3-4-x-1-2-Black-Bushing



Or maybe someone else can provide a link to the correct fitting?



Thanks, James

Rod

Bushing

Hi- For a hex bushing either one will do. This black iron bushing is very common and should be available in any plumbing or hardware store. If you don't mind spending a bit more you can get this bushing in brass. As it doesn't corrode /rust, a brass bushing is easier to remove at a later time. Either type is fine.

Since you are new to steam I might mention that there are somne very good books on steam in the Stop section of this website. The best book to start with is "We Got Steam Heat"

http://www.heatinghelp.com/products/Books/5/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence

This book is written for the homeowner who is new to steam. It's easy, humorous reading and in an evening or two of reading. will put you light years ahead in your knowledge of residential steam heating.  The tips it gives you easily pays for the book a hundred times over.

- Rod

Steamhead

Looks like whoever installed that boiler

wasted no time reading the instructions. I bet you're getting some wet steam. 

Charlie from wmass

You will not be able to put a Gorton# 2 into a bushing

with that elbow that close to the wall. Steam vents are sized by the length and diameter of the main they are on. About how long is it from your boiler to the end of your mains?

If a #1 is too small a gorton # 2 can be installed with a union and a pipe nipple. The bushing would be a 3/4"x 1/2" NPT bushing. I would go for brass. I would install this in a 3/4" iron union on a 3/4"x2" iron pipe nipple and thread the nipple into the current vent location. You may need to go with what we term a close nipple if there is not the height to install the 2" and the Gorton #2. There are other options but trying to keep it basic

JamesC in Stamford CT

bushing

Thanks Charlie for the observation about the size of the Gorton G2 and the distance to the wall. But my photo was a bit deceptive, there's probably an inch or more between the edge of the piping and the stone wall. Since I've already ordered the G2 and the bushing, I'll wait until they arrive and then see if I need other fittings or not.



Btw, you asked the distance -- the piping from the boiler to the end of the steam main is about 75 feet long (actually it's only about 10 feet as the crow flies, but the mains for this branch snakes all around the corners of the house for a full 75 feet before it ends up at the old vent in the picture). That is why I want the G2, to eliminate air from the main as fast as possible.

Johnny13

I think this was a reply to me

Looks like whoever installed that boiler

wasted no time reading the instructions. I bet you're getting some wet steam.



Boiler was in place when I bought the place. How would I know if the steam was wet?

Steve_175

Wet Steam

"How would I know if the steam was wet?"



Are you rads spitting water? Is your sight glass bouncing or do you see water cascading down the tube on the inside. Do you hear any kind of gurgling or swooshing in any of the pipes.



It is very important that the near boiler piping goes vertically a minimum amount. Otherwise the steam will pull water into the pipes. The boiler manual will have a diagram showing how it should look. You should get that piping redone. It will cost some $ to fix it but you system will run more efficiently.

Read these two articles that Dan wrote, they will explain a lot.



Also post some pics of your boiler from different angles.



http://www.heatinghelp.com/article/11/Hot-Tech-Tips/128/A-Steam-Heating-Primer



http://www.heatinghelp.com/article/11/Hot-Tech-Tips/263/The-Speed-of-Steam

Johnny13

I will take some pictures

I don't have any vents spitting water, and my sight glass just shakes a bit when the boiler is running, but the range of the bounce is not very large or violent. I have one radiator ( a small one in the bathroom) that sounds a bit like the ocean sound of a sea shell. It is a pretty relaxing actually. Everything else is pretty quiet. Occasional ticking. A bit more frequently a quick metallic clang that sounds like a some hinged metal thing snapping shut.