Replacing / Installing main line air vents on one pipe gas steam system
What size of air vent's should I buy? I didn't want to pull them off without having replacements in hand.
Also pulling them off - as simple as PB Blaster and plumbing wrench? Or are they likely to be "steam welded" on like other steam fittings?
Thanks.


Comments
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What vent -- or vents -- to put on depends on the length and diameter of the steam mains. Can you get us that information?
As to replacing them -- you should be able to get those off OK. Sometimes just some muscle, sometimes PB Blaster or other confections (someone on the Wall swears by a 50/50 mix of acetone and WD-40) and patience. They'll usually give up. That said, that location is not really ideal for vents, though it can work. What you need to do is protect them from condensate and possible water hammer, and the easiest way to do that is to raise them and offset them using a few nipples and elbows.Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England1 -
Diameter is 2".Jamie Hall said:What vent -- or vents -- to put on depends on the length and diameter of the steam mains. Can you get us that information?
The 90 with the vent on it is 55-60 ft from the boiler.
The 90 without the vent (just a plug) is 10-15 ft from the boiler.
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You will probably need a lot more venting on the 60 ft main. I would try putting that Gorton #1 on the 15 ft main and then a B&J BigMouth on the long main. Getting the plug out of that one main is likely to be a real chore.
BobSmith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
Vaporstat with a 12oz cut-out and 4oz cut-in
3PSI gauge2 -
Thanks Bob. The B&J big mouth is $84 vs $28 for the Gorton #1 at supplyhouse.com. Worth the extra money?BobC said:You will probably need a lot more venting on the 60 ft main. I would try putting that Gorton #1 on the 15 ft main and then a B&J BigMouth on the long main. Getting the plug out of that one main is likely to be a real chore.
Bob
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> @branimal said:
> You will probably need a lot more venting on the 60 ft main. I would try putting that Gorton #1 on the 15 ft main and then a B&J BigMouth on the long main. Getting the plug out of that one main is likely to be a real chore.
>
> Bob
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> Thanks Bob. The B&J big mouth is $84 vs $28 for the Gorton #1 at supplyhouse.com. Worth the extra money?
Barnes and Jones says Amazon is the cheapest place to get a big mouth since that where they sell them directly to the customer. You also get free shipping and possibly no tax depending where you live.1 -
B&J big mouth it is. Hopefully that plug on the main will come out with an impact wrench and square bit. If I can even fit it in there. Thx0
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I know this is an old thread, but I'm finally getting around to get these main vents on. The plug on the 90 won't budge. I tried heating it with MApp gas (60 seconds) and loosening with a large crescent wrench with a cheater bar). I smacked the plug with hammer, tried tightening it, and repeated heating. Nothing. I don't want to risk any damage to the system b/c its freezing outsise.
I tried loosening the little vent on the far (60ft) vent. Didn't budge. Can I heat the black nipple with mapp gas to get it off? PB Blaster?
Plan is to upsize to 3/4 (reducer), put a 90 el + nipple +90 el + nipple then Big mouth vent to get it away from the condensate.
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More heat, you won't overdo it unless you are using an oxy-acetylene torch! Penetrants like PB Blaster probably won't help much because of the pipe dope or teflon tape in the way.
What length pipewrench are you using? Try adding a section of pipe to the wrench for more leverage.
I was in the same situation as you with a 1.5" plug at the end of my main. PB Blaster didn't help at all. I used a 3ft pipe wrench and it took some effort but it finally budged.
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crescent wrench not my fave. Try an 18 or 24” pipe wrench on the base of the vent.
The vent is brass, it will give
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el1 -
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I'll give the stuck vent a shot with an 18" pipe wrench.
Good point…. I was thinking I just needed to distance the vent from that elbow on the main. But I guess condensate will shoot up my 3/4" 90 elbows vent path. I'll use a couple of 45els so I have pitch. Thanks for the heads up.
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Condensate doesn't shoot up, it trickles. The "slug of water" is mythical.
Now if you have full-on carryover, you could have gallons of water getting forcefully shoved through your main, but that is a problem you should solve, not work around with extra pipe and fittings on your main vent.
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el1 -
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I mean the boiler puking gallons of water up into the main resulting in a dramatic drop in water level as viewed from the gauge glass, like in this classic video from early in my steam experience:
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
Regardless of the condensate load, we do not want it to pool in low spots in the vent runout where venting air may push it into the vent itself and make it spit, or worse.
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Bburd0 -
I agree and never meant to say otherwise 🙂
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
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Certainly, using two 90s at each joint. But that is not the piping plan the OP described above. The way I read it, he seemed to be proposing one 90 per elbow.
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Bburd0 -
Got it installed. Not an ideal location as it's b/w the joist bays.
On the first boiler cycle, I saw a little steam and a gurgle of water come out of the Big Mouth vent. Next cycle I saw just a bit of steam.
Next step is to remove the 3/4 plug off the steam main vent location closer to the boiler. Will try more mapp gas on the 90el and use a pipe wrench plus cheater bar. I have a Gorton #1 on hand.
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