Counter-productive main vent?

MrDvorak

I have just realized that one of my big vents most likely works against the efficiency of the system.



I have a long loop that is risen 10ft away from the boiler right underneath the ceiling for extra headroom and so it is effectively branched into two returns (picture below). The short branch has no radiators attached to it, it just drains condensate that never reached radiators. I guess I should keep this shortcut return as little vented as possible as it is only there to drain condensate and to lose heat. I wonder if its vent (V2 in the picture) should be made slow or if it could be eliminated altogether? It heats nothing but the wet return. Instead, I guess I should move V2 to the other return next to V1 to help vent the long section with radiators. At this moment, V2 gets hot way faster than V1, for nothing. Hmmm...

Jamie Hall

Well now...

You could, I suppose, take that vent off and plug the opening.  If the system really is as you have drawn it, what it is doing is allowing steam to get to that junction faster.



However, if you do do that, you will want to increase the size of V1 -- a lot.  To make up the difference.



In either case, for efficiency, both those dry returns should be insulated just as the steam mains are (I hope), as they will get steam in them.



Must admit that's a slightly odd setup...

MrDvorak

Agreed

Yes, I completely agree with you. All that vent does is it gets that section between the boiler and the junction vent faster. It is a little strange setup, the junction is literally in a cutout in a wall between two rooms. Without it, though, one of the originally finished rooms in the basement would be useless I guess as it gets the pipes above our heads.

MrDvorak

Plugs

I think I know what is going on. I found plugs right next to last radiators on both main loops (plug "P", the second loop is not in the picture). Some knucklehead must have plugged them and then installed a massive boiler with a 3-15 PSI pressuretrol to ram the steam through. That means that I heat steam and pipes for all dry returns. The fix should be easy, but I have less than 7" of clearance above those plugs. Gorton #2 will not fit. Any suggestions for fast venting low clearance main vents? Thank you.

Jamie Hall

Now that could be a problem

venting with low overhead clearance can be difficult.  Remember, though, that what you are trying to do is to get the air out, and protect the vent from slugs of water.  Street elbow out of the plug, over, T up and you may have enough clearance.  Put an additional bit of pipe -- say a foot or so of pipe -- with a cap on it beyond the T (which will look like it doesn't do anything) and any stray water will go that way, rather than up to the vent.  Make sure the whole thing drains back to the plug, though...



On the other hand, if this is in the basement, is the clearance to a finished ceiling?  If so, can you knock a hole in the ceiling?  I've done that...



Or as a last resort, can you run a line to somewhere on the next floor up and stick the vent on that?



As to what the knuckleheads did to give you the existing set up, and why, better not to ask... One sees the dangdest things.

MrDvorak

So far so good

Yes, the basement ceiling is finished. But, if I were to make a hole in there, it would not be the first one by far. I blocked the rogue vent and V1 seems to get warmer quicker now. I am sure moving the vents to where the plugs are would speed up the warm-up sequence even more.