Main vent questions - newbie

BostonDad · June 27

My daughter and son-in-law purchased a 1920 home in Boston last summer and I've been slowly beginning to correct some problems with their one-pipe steam heat system. I've been following this forum (thanks!) and have read Dan Holohan's book.

The system is very quiet. The primary issue is the very slow heating of the radiators towards the end of the primary main.

The main vent was clearly way undersized. The longest section, a 41' long 2" main, had a single Vent Rite 35, with an additional Vent Rite 35 at the end of a 10' dry return. I replaced the first vent with two Gorton #1's and removed the vent on the return. Since then, I've read advice on this forum that two Gorton #2's would be more appropriate. I have a couple of questions before I proceed.

First, I don't have a lot of head room and installing Gorton #2's would mean locating them between the floor joists, about two inches below the subflooring. Do I need to be concerned about steam damaging the subflooring in the event of sputtering or a vent failure? Am I better off going with eight Gorton #1's on a humungous antler so that I can keep the vents lower down? Or should I be considering another brand? I saw a number of people on this forum reporting trouble with the build quality of their Gorton #2's in the past. Has this issue been addressed?

Second, the vents are located off of a 3/4" pipe at the end of the main, immediately after the return tees off. Due to the pitch of the pipe, part of the pipe likely has a low pool of water. Is this going to choke the flow of steam on it's way to the vents? Or cause a water hammer once the venting is increased? I've attached a picture. The green line is from my laser level.

Thanks,
Aaron

ethicalpaul · June 27

Yes it could cause a water trap there, preventing air from exiting the vents. Have you ever felt air leaving these vents?

I wouldn't worry about changing them out for a #2 until you see how well they vent. You can time how long it takes the steam to fill the main.

There is a lot of advice in this forum that pushes you toward massive main venting that in my opinion is not warranted.

Jamie Hall · June 27

Well… I wouldn't worry about the Gorton #2s. There have been some QC issues, but in general they are a good reliable vent.

Now… that sloping pipe. As it is, it could be a problem. However, I think that if you take the reducer off under the big pipe, and put a 45 on there angled up with say a three inch nipple, then a 90 towards the room (to clear that other black sloping down in back) and your Gortons on there it should work. Adequate headroom. There will still be a bit of a puddle there — can't help that — but it may work just fine.

109A_5 · June 27

You could disconnect the pipe at the Red arrow add two 90 elbows and a few nipples to pitch the vent pipe the other way. However I'd wait and see if it is actually needed. If the Steam / water vapor seems to affect your wood in the area of the main vent you could use aluminum flashing (or the like) as a barrier.

Personally I like the Barnes & Jones Big Mouth Main Air Vent. The air exhaust port is not at the top and it is threaded, so more versatile. Additionally this vent can be dissembled for service, etc.

BostonDad · June 28

How large a pipe wrench would one need to loosen that pipe?

Steamhead · June 28

2- to 3 foot, plus a torch to heat the joint.

Main vent questions - newbie

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