Adding main vents where there none atm

mygardenshed

Our new heater is up and running fine. Install thread here: https://forum.heatinghelp.com/discussion/185857/new-steam-boiler-install#latest
I’m now in the process of getting it balanced. The only vent at the moment is on the condensate return. There was a Hoffman No. 4 that was shot so I bought a Gorton #2. It was too big for the current vent so I returned it and bought a Dole No. 4 which is basically a Hoffman but has 3 vent holes as opposed to the Hoffman’s 1. Seems to be venting just fine.
My question is:
There are currently no vents and the ends of the mains. Should I try to install one if I can?
The one main has a tee and a 90° for the final radiator takeoff. Would it be beneficial to change the 90° to a tee and install a vent there. The other main is behind a finished wall and I’m not too thrilled about tearing into it there would be no benefit.
Some photos:


After the radiator takeoff the main drops down into the wet return .

Jamie Hall

The idea of a T where you have circled and adding a vent there is a good idea. However. Unless there is a handy union somewhere nearby, it could be a real job...

Steamhead

Where is that Dole #4 installed on the system? Post a pic. Also, is this a one-pipe or two-pipe system?

mygardenshed

Jamie Hall said:

The idea of a T where you have circled and adding a vent there is a good idea. However. Unless there is a handy union somewhere nearby, it could be a real job...

There is a union on the radiator piping. As you can see there’s not enough room for a very large vent.

mygardenshed

Steamhead said:

Where is that Dole #4 installed on the system? Post a pic. Also, is this a one-pipe or two-pipe system?

Two pipe system. Seems to be running at a nice pressure.
The other day I went through the radiators one by one, system off of course, and removed each trap cage and cleaned the trap base. While the cages were out I gave them a good wipe down and heated them up with a heat gun and made sure they were opening and closing. Also while the trap was open I sent a shot of compressed air down the condensate line via the port at the base of the trap to be sure there are no obstructions.
Discovered one trap that’s suspicious. I think it’s in the pipe leading from the trap and into the return. Replacing the piping shouldn’t be too bad as it’s exposed in the basement.

mygardenshed

Follow up question is if I install a vent at the location discussed above and not install one at the end of the other main will this lead to an imbalance? I’m thinking yes.
I may install one and if it creates trouble due to an imbalance I can always put a pipe plug in it’s place.
Thanks

Hap_Hazzard

When I discovered I had no main vents a few years back, I installed the biggest vents I could find on the last radiator on each branch as an interim measure. A "D" radiator vent is as fast as a #1 main vent. Unless that radiator happens to be right next to your thermostat, you might give that a try.