Upgrading/Relocating Main Vent on 1/8" End-of-Main Tap (Water Spitting & Clearance Issue)

Hi everyone,

I’m looking for some advice about my main vent. I just had my ancient, wildly oversized boiler replaced with a properly sized 260 sq ft steam boiler. The installing plumber replaced all of my radiator air vents, but he didn't touch the main vent. When I asked about it, he just told me I could swap it out myself.

The Setup & Problem:

• Main Pipe: One single, 40-foot run of 2-inch iron pipe leading up to where it drops down at the dry return.
• The Main Vent Tap: A 1/8-inch tap located directly on the side of the downward-pointing elbow right at the dry return drop.
• The Issue: The old vent was just a standard radiator vent that spit water. The plumber said to just replace it, so I just grabbed the largest vent I could find with a 1/8" thread (a Gorton No. D) and screwed it in. I know now that a radiator vent is completely wrong for a main, and of course, it didn't fix the issue. It still violently splashes/spits about a cup of water every single time the boiler pushes a new wave of steam. I also now realize this tap is right in the "splash zone" where fast-moving steam and condensate crash into the back wall of the elbow.

My Proposed Fix & Questions:

I want to upgrade this to a proper, high-capacity Gorton 2 or equivalent to vent this 40-foot main, which means stepping up from the 1/8" tap to a 1/2" NPT vent body. I also need to offset horizontally about 6 inches to clear an obstruction and get the vent into an open joist bay.

Additionally, the current tap seems to be pitched slightly downward, which is why I'm thinking a 45-degree elbow right from the tap makes the most sense to immediately create an upward pitch.

To get out of the splash zone, clear my obstruction, and prevent water from pooling in the offset, I am thinking about this sequence of brass fittings:

1. Start at an Angle: A 1/8" brass street 45-degree elbow threaded directly into the main tap, angled upward to counteract the downward-pitched tap.
2. Offset & Climb: A short 1/8" brass nipple running diagonally up to get my 6-inch horizontal offset while maintaining a steep upward slope for drainage.
3. Turn Vertical: A second 1/8" 45-degree elbow turning straight up toward the ceiling.
4. Upsize & Elevate: A 1/8" to 1/2" brass reducer/bushing, followed by a vertical 1/2" brass chimney (around 8 inches) to keep it well above the splash zone.

Questions I have:

• Does using a 45° offset right off the main tap make sense for draining condensate back, or should I upsize from 1/8" to 1/2" before doing the 45-degree offset?
• Is an 8-inch vertical 1/2" riser above the offset tall enough to keep splashing water from reaching the Gorton No. 2 or equivalent vent?
• Or, what is a better solution?

I am attaching photos of the original vent on the elbow, the Gorton #D I installed on the elbow, and some more photos of the piping so you can see what I'm working with. Any insights would be greatly appreciated. Thank you!