Location of Main Vent

MikeyB

Have a about a 10 foot section of 2" steam main that has no air vent on it, what would be the best location for an end of main vent? Remove the 2" X 1" Elbow and put a 2" X 1" heel tee in its place and put the air vent on the top run of the tee and mount it as high as i can. Or cut in a tee on the 1" drip and install an air vent there? Thanks

Rod

Possible Main Vent Location

Hi - What's your "A: dimension?  The easiest "fix" would seem to be that if you have enough height you could put a tee for the vent where the union is at the moment and install the union below the tee.  From the new tee you could route it upwards and install a new vent where it was convenient. The water line to the lower part of the tee would have to at least 28 inches above the boiler waterline.

Just a thought

- Rod

Steamhead

How long is the other steam main

and what pipe size is it? 

MikeyB

Main

Thanks Rod and Frank, the other main is 2" and approx 40 feeet long, the one pic of me is measuring down from the bottom of that shorter main to the 28" mark, which brings me just about an inch or two above that dry return for the shorter main, the other pic is the end of the 40 foot main, the venting as you can see will need some attention, im thinking at least (2) Gorton #1's for the longer main and (1) Gorton #1 for the shorter main? I was thinking for the venting of the longer main (the vents are in a crawl space) that I can utilize a unsed 2" X 1 1/4" tee thats about 6 feet upstream of the vents in the crawl space now and put the vents in the bull of the unused tee, this way the vents will be easier to service in a meter closet compared to the crawl space, then i might have to increase the venting on the one radiator thats last on that longer main to accomadate the 6 feet of 2" runout.

Steamhead

What I'd do

is put a Gorton #2 on the long main.



Then, before doing anything with the short main, start the boiler and see how long it takes for the steam to reach the end of the short main AFTER the Gorton #2 on the long main closes. Base your short main vent selection on that.

MikeyB

Main Vent

That sounds good Steamhead, thanks. What do you think would be a good air vent for a 1" vertical riser that are approx 20 feet long ? I could remove the angle radiator valve thats on the attic radiator now and install a tee in its place and time how long it take to get steam out of the top and select my air valve off of that

Steamhead

Where does that riser

connect to the steam main? Long main or short, and where on the main?

MikeyB

Riser

Its connected to the longer main, about halfway down the main , there are 4 takeoffs on the longer main, and this 1" take off  supplies the 2nd fl bedroom and one of the attic radiators its the 2nd take off on that main. This is the same riser i was talking about in my other post about Horizontal take off EDR. There is also another 1" riser off the short main (first take off out of 3) that used to serve a rear bedroom radiator that is removed ( i did a heat loss for this room to figure it into the replacement boiler as well) and another attic radiator that has a EDR of 17.5, I am thinking of installing riser vents on this riser as well, approx 20 feet long. Thanks for your help Frank  

Steamhead

Again, try it first with the new Gorton #2

to see how it behaves. The steam will definitely reach it more quickly. If it's still slow, try my suggestions from the other thread. 

MikeyB

Vents

That sounds good Steamhead, thanks, do you remember the thread when you and Gordo had to install a Gifford loop to put the new return line you had to install above the water line under water? I was thinking i could do the same thing with these dry returns instead of a False water line. I could only bring a FWL up high enough to cover those 2 dry returns about an inch or so, because i will start to lose the 28 inches from the bottom of that short steam main to the top of the U-Bend of a FWL, (would an inch or 2 be enough to cover those 2 dry returns?) im not even sure i could use a Gifford loop? you can see my post on the 2nd page FWL or Gifford loop, thanks again Steamhead

Steamhead

If you're replacing the boiler

the easiest thing would be to set it up on blocks, just enough so the lowest water level would just submerge the returns all the way to the drip connections. I'll bet the original boiler's water level did exactly that.

MikeyB

Level

Thanks again Steamhead, i know i can replace the dry returns and make them wet returns, alot more work, but another option as well. Thanks for all you do.

MikeyB

Location

If I do have to add a main vent to that shorter main, whats the best location? i was thinking along the same lines as Rod, to keep it lower than the main then bring it back up?

gerry gill

Don't know if this will help

you with your decisions but you don't necessarily need 28 inches of 'a' dimension as long as you match your maximum boiler pressure to the available 'a' dimension you have..this old data sheet from 1919 heating and ventilating magazine may help.

MikeyB

Charts

Thanks Gerry, I have to look that one over