What is the shortest main vent?

erickehoe

I need to replace my main vents. I tried to use a Gorton #1 but it's too tall to screw in because there is piping right above it. I was going to do a 90 out from the main but even that is too big to fit into the spot.

So I'm wondering: what is the shortest, stubbiest 3/4" main vent?

kcopp

Well if you really in a pinch you can use a Varivalve straight radiator vent. Open it up fully. They are better than nothing...

acwagner

Got a photo of the situation?

I don't think there are any main vents smaller than a 90 degree fitting. I recall you have a photo of your boiler install and the main vents were in that photo. Are you relocating your main vents?

Jamie Hall

If a Gorton #1 or a 90 elbow won't fit, you're going to have to get creative. As @acwagner says, picture please.

erickehoe

The other main vent is easy to adjust, but on this one you can see the base of the old vent that was in there. The previous owners had a broken radiator vent in that spot. This main is 3” and about 20 feet.

ethicalpaul

That photo is cryptic 😅

erickehoe

Can you use a Hoffman 4 as a main vent? Or does it need to have a float.

acwagner

What's going on in your photo? I don't see the vent location.

acwagner

I think I see the vent location in your photo. Does it not fit because of the pipe insulation on the pipe above it?

erickehoe

The Gorton is actually hitting the pipe itself.

acwagner

What's the fitting that you're trying to connect into? Looks like a small union is there from the photo. Hard to tell.

You might try getting whatever fitting is in there out and put in a street 90. Then you get get it over and away from the pipe above.

nicholas bonham-carter

Do you have dry returns, or is this a counter flow system?
The main vent could be put on the vertical drop down to the wet return, mounted as high as possible though.—NBC

erickehoe

I tried a street 90 but unfortunately that doesn’t work either. As I rotate it it runs up against the other pipe.

I’d like to try the Hoffman 4; since it tapers at the top I think it’ll work. But if not I like the idea of using the vertical drop down.

acwagner

A vent is better than no vent, but the Hoffman 4 doesn't have much venting capacity--it's basically a small radiator vent. You probably won't see much improvement.

It's not the best practice to put the vent at the end of the line like that--makes it susceptible to being damaged if water hammer occurs.

You might consider moving the location further up the line. A much bigger job, but that will get it out from under all the obstructions and will enable you to put appropriately sized vents in.

erickehoe

Is there a how-to on tapping black pipe if I made a new one?

coelcanth

it's really hard to tell from your photo, but maybe there is a chance you can use something like a barnes&jones bigmouth.. since they can be installed in two pieces;
the very short tailpiece first, and then the valve body itself (without having to rotate this part to thread it in)

mroberts5

Not sure if this will help you, but when I installed a big mouth in one location I had to separate the pipe fittings from the body, thread that in, then reassemble. That bought me maybe 1/4".

erickehoe

@coelcanth @mroberts5 so it’s a two-piece vent, and the top portion doesn’t need to be screwed in? Does it just snap in place? I think that would work for me if so.

mroberts5

It has a screw on nut, like a union.