Which valve would be the best for main venting?

NY_Hammer

Hoffman 75 or Gorton #2 ?

I have head different opinions, what would you recommend?

Thanks

BobC

They are both good vents but the Gorton will vent at twice the rate for the same money. The Gorton will close before the Hoffman will.

Bob

NY_Hammer

I am trying to replace this main vent, see the pictures, it's a 2in about 35 feet main.
The space is a problem there, I am not sure if Gorton#2 will fit.

BobC

The Gorton #2 is about the size of the old 12oz tuna fish cans so you will have to judge if you have room for it to swing. You could build an antler to mount multiple #1's (3 #1's is about equal to a #2) but make sure you can get a little slope on it so water does not get trapped. How long is that main and how many vents will you need?

Bob

Ba11zooka

I happen to have measured a Gorton's #2 last night, and it's about 7" from the top of the vent cupola to the bottom of the threading.

The venting comes out of the side of the cupola rather than out of the top, so that might be a factor in how close you can put it to an overhead surface, too...

Fred

I use hoffman 75's. They are reliable and they do stay open longer. They don't vent as fast as the Gorton #2 but with a 2" main X 35ft. You need enough venting for about .805 sq. ft of air. I'd go with 2 Hoffman 75's or 2 gorton #1's or 1 Gorton #2

NY_Hammer

by the way any idea what the current vent is?

Ba11zooka said:

I happen to have measured a Gorton's #2 last night, and it's about 7" from the top of the vent cupola to the bottom of the threading.

The venting comes out of the side of the cupola rather than out of the top, so that might be a factor in how close you can put it to an overhead surface, too...

When you say bottom of the threading is it actually where top of the threading or the very bottom of the vent? Like is it a installed height of the vent or the height of the vent before the installation?

Thanks

Abracadabra

NY_Hammer said:

by the way any idea what the current vent is?

Looks like a MOM #1, it's similiar to a Gorton #1 in venting capacity.

Ba11zooka

NY_Hammer said:

When you say bottom of the threading is it actually where top of the threading or the very bottom of the vent? Like is it a installed height of the vent or the height of the vent before the installation?

That approximate 7" measurement is the total height of the vent before the installation - mine threaded about a half inch into the 1/2" FPT to 3/4" MPT bushing that I used to install it, and that bushing then probably added another 1/2" to the total height, bringing the installed height up to 7" .

I've attached a picture - it fit very easily into this space that was 9" above the top of the elbow's threading.

ww

I've been experimenting with both these vents. I put the Gorton 2 and a Gorton 1 on the long main and a Hoffman 75 and Gorton 2 on the short one. Maybe I'll move this around too as well since a comment was made regarding the time it takes for hoffman to close.

It's very important as someone mentioned to slope these correctly as well..and it's advised that vent is 6 inches high above pipe thread and 15 inches back towards the slope of main as well so there will be pitch to get water out.

They say that if you screw them right in they can get clogged quicker. Use a level and watch the pitch.
Use unions to attach.

They have alot of ways to do this...and I've tried them..such as taking vents off and timing how long it takes to get air out..

You can also use formulas to see how much cfm by volume to get some idea on 2 inch pipe. pi r squared x length....convert to inches..so........

Disregard all this math stuff if it isn't your thing

3.14 x 1 x (convert feet to inches)...35 x 12 = 420..

3.14 x 420 =1319 cu inches....to convert inches to ft...12x12x12=1728...so divide 1319/1728=0.7634...this is the cfm
to figure out cfm of the pipes you would convert inches to feet.

So if you approximate 0.250 cfm on short main and 0.510 on long depending on boiler position...you can see what I did above is a start. The comments here are on the right track. Looking at the various cfm for the gorton and hoffman you can see.

You can look at the Gorton site and other areas here and it will show you how to make these antlers and menorahs as they are called.

What I'm going to do next is apply some of the same formulas to see if they work with the branch lines to the radiators. I find alot of this is trial and error but I like to figure out how things.

If you look at photo attached you will see the setup with the vents is going back toward main and has a pitch so water can flow out to return. You may also notice that I've read in a number of places to use street elbows...I prefer using nipples going directly into the 3/4 elbows because I know about flow rate on pipes and don't want to lose any advantage of stopping rate of flow to get rid of the air.

After all a 3/4 street elbow has a threaded end of half an inch. 1/4 inch less here can lose 50 percent flow according to the chart depending on feet...so four of them could equal 200 percent loss of flow...of course this doesn't apply to the one with the gorton 2 because it's half an inch to begin with and has the cfm based on that .. but I set up with what I have anyway.

NY_Hammer

Ba11zooka said:

NY_Hammer said:

When you say bottom of the threading is it actually where top of the threading or the very bottom of the vent? Like is it a installed height of the vent or the height of the vent before the installation?

That approximate 7" measurement is the total height of the vent before the installation - mine threaded about a half inch into the 1/2" FPT to 3/4" MPT bushing that I used to install it, and that bushing then probably added another 1/2" to the total height, bringing the installed height up to 7" .

I've attached a picture - it fit very easily into this space that was 9" above the top of the elbow's threading.

Judging by your picture you have a horizontal nipple out of the main and 45 elbow.
Is it ok to install this way?
I have another shorter main with a similar setup at the end of it, but the tapping closed with a plug I can't remove.
and the space is very limited there so I can't drill a hole on the top of the main.
You can see this discussion about that:
http://forum.heatinghelp.com/discussion/151304/what-is-the-solution
But I could do something similar to your set up and install Gorton #1 there IF it's a good setup.
I can add another vertical nipple after the elbow before the vent to place the vent higher it's not a problem.

NY_Hammer

Also in regards to placing the main vent I read somewhere that
"They should be a minimum of 12"-15" from the end of the main, never in a tee at the end of the main."

Why not in a tee at the end of the main, as I do have tapping exactly there?

Ba11zooka

NY_Hammer said:

Judging by your picture you have a horizontal nipple out of the main and 45 elbow.
Is it ok to install this way?

I have another shorter main with a similar setup at the end of it, but the tapping closed with a plug I can't remove.
and the space is very limited there so I can't drill a hole on the top of the main.
You can see this discussion about that:
http://forum.heatinghelp.com/discussion/151304/what-is-the-solution
But I could do something similar to your set up and install Gorton #1 there IF it's a good setup.
I can add another vertical nipple after the elbow before the vent to place the vent higher it's not a problem.

Yeah, I was working with the existing solution - a nearly horizontal nipple with a 90 elbow (so the vent is still straight up and down) - this is definitely inferior to vertical or 45 nipple, but it's all that I could manage with the setup, as the main is right up against the joists in this location.

I've read that a nipple 45 off the main with a 45 elbow to get the vent straight up and down is an acceptable solution, if you're desperate for clearance, but it sounds like you could set up to go horizontal out to a 90 elbow and could then add a vertical nipple on top of that elbow? That sounds like it's at least partially a superior solution to mine!

SWEI

Design high capacity vent that's half the height of a Gorton #2 and you could probably build a nice little business around it.