Main vents buried in finished walls

bombaloo

Hello

So I posted previously how I wanted to insulate my pipes to improve my system and basically the near boiler piping was ripped apart. Anyway I’ve been understanding my system more and I found that the main vents have been buried in walls and ceilings for over 10 years when the previous owner had some walls put up in the basement. Somehow the Contractor did not realize he was burying vents. Long story short I was doing some renovations and uncovered them. I have no idea if they are still working. The system is terribly balanced so I suspect they are not.  I would like to do the test to hear air hissing out of them. Can anyone tell me any info about these vents and what model to replace then with.  

Jamie Hall

They're cute. Even if they were working, they aren't meant to be main vents. How long are the mains, and what diameter are they? Then we can make suggestions for better ones.

Also, what is that piping arrangement in the last photo? Specifically, what are the two horizontal pipes which then drop down a little ways and join together? That worries me a bit.

bombaloo

One main is 52 feet. The other is 42 feet but has 2 extensions off it running to an addition to the house through a crawl space. The original mains are 2 inch iron. The addition pipe is 1.5 copper. I’ll add another angle but basically the 2 mains combine and the vents come off it.  

Jamie Hall

So am I seeing one main coming from one direction, and another main coming from the opposite direction through the wall? They both need vents on them -- but worse, the must not join like that above the water line of the boiler. They both need to go down -- individually -- to whatever wet return is lurking out of sight at the bottom of the picture. The way they are now it will be almost impossible to get a decent balance out of the system.

Going to be a bit of a bore -- not really a do it yourself job, unless you are very handy with pipe and pipe wrenches and all -- but not that hard tor a good plumber.

bombaloo

Yes they join above the water line and that single pipe goes straight down then horizontal pipe leads back to the boiler. Can you give a quick explanation of why they need separate returns until lower than the water level. I will be contacting a professional on this website. Also assuming that was taken care of what would be your suggestions for the main vents. They each have a main vent right now

Jamie Hall

The reason they need to drop down is to avoid having steam from one main get into the other and shut its vent before all the air has gotten out of it, making it so that any radiators on that section will be much slower to heat than the others not so trapped.

I'd suggest a Gorton #2 for each line, but if you get a good man from this site, he may have a better idea..

bombaloo

Would something like this be the Solution 

Steamhead

As long as the junction point is below the boiler's waterline, yes.

Also @Jamie Hall is correct, those cute little Hoffman #45 vents were meant to be used on convectors, not steam mains. They lack the needed capacity. Gorton #2 vents are the right choice here.

bombaloo

Thanks. Should Groton #2 ‘s be moved up the main 10 inches or so or is it ok to have them exactly at the end of the main as these ones are 

Steamhead

10" back is preferable, but I've seen them work OK right at the end.