New Main Vents

bergensteamguy

Hello Steam Heads, I have a question for all your pros. I have a long main, 50ft. It has one main vent on it before the last riser. I would like to add an additional vent past the last riser and 1 ft before the main ends and drops into the dry return. My question is about how to add a new main vent. I have seen two methods. One is you cut the pipe, add a tee and have the main vent come off that. The other option is just to tap into the existing main and add a vent off the side of the main pipe. See my diagram. My question is one better than the other? Does it matter, just as long as it has the proper venting?

Jamie Hall

It doesn't matter -- sort of. I'd prefer to see the tap, if you go that route, on the top of the pipe or 45 degrees off the vertical, rather than on the side -- but you may not be able to get the drill and tap in, depends on access. Cutting the pipe and adding a T is a bit of a hassle unless you have a handy union somewhere on that length of pipe, or can add one.

ethicalpaul

Tap off the top, not the side, if you must, but my first question is: what do you hope to gain? Do you suspect that the location of the existing vent is harming you?

yes, a main vent positioned after the last radiator tee is probably better, but the practical difference seems to be nil based on the way you described it. Unless it's some large distance before the last tee.

bergensteamguy

@ethicalpaul, the existing main vent is about 7ft from the end of the main and about 5ft before the last riser. The radiator leading to that riser never gets as warm as the others. I feel that is due to where the main vent it placed.

ethicalpaul

It's not helping, true. Report back and let us know if it got better. What size vent is on that radiator? You might try a larger size to rule out something else like water pooling, but you'd probably know if that was a problem from the knocking.

JUGHNE

What do you have there now for a main vent?

Mad Dog_2

Yes...Main vent should be PAST the last take off.  Cutting in a tee 15" back from the vertical drop in to the wet Return is ideal. Sometimes, this is not practical because of space, logistics, asbestos and I'm happy to get one in anywhere in the Vicinity.  If rather drill & tap a Cast Iron fitting for the beef & girth, but sometimes I've got to tap a pipe. With Low pressure steam (2 psi & below) its not an issue. Tap atleast  a 1/2 " thread if you can and pipe it up as high as you can just under the floor boards.  Pitch your piping so that you don't Ship water up in to the Gorton # 2.   Good luck  send pics  Mad Dog 

Steamhead

ethicalpaul said:

..........you'd probably know if that was a problem from the knocking.

Not always. We've run into situations where a plugged return caused water to back up into a steam main and shut the vents- and it didn't bang. Weird, but it does happen.

JUGHNE

IIWM, I would tap the top of the pipe a foot or more before the end of the main.
A 1/4" tap will handle one Groton #2. (easier to tap 1/4 than 1/2 and better fine thread connection than you would get with 1/2" threads).

Also install a second G2 where the existing vent is now.

The two of them will vent the main quickly.
When steam gets to the first one it will close and then the 2nd one will close shortly thereafter.

Can you show us the present end of main and existing venting set up?

Mad Dog_2

Many times you can't fit a drill between the top of the main and the bottom of the subfloor.  Do your best.  Mad Dog 🐕 

ethicalpaul

Steamhead said:

Not always. We've run into situations where a plugged return caused water to back up into a steam main and shut the vents- and it didn't bang. Weird, but it does happen.

Thanks Steamhead, that's a great puzzler!

The reason I brought that radiator's vent up (and I'm curious if you agree generally) is that 5ft of main after the main vent, although not optimal, seems like it wouldn't be enough to cripple a radiator--but it would depend on the radiator's venting (both if it's the right size and if the vent is operational) and the length of the supply to that radiator.

If the only problem is that one radiator I'd definitely try the very easy effort of increasing the venting there before all the effort of making a new main vent port.

Jamie Hall

If this is one pipe steam, just increasing the venting on that one radiator is much the simplest approach.

bergensteamguy

ethicalpaul said:

It's not helping, true. Report back and let us know if it got better. What size vent is on that radiator? You might try a larger size to rule out something else like water pooling, but you'd probably know if that was a problem from the knocking.

I have a varivalve on the radiator. i believe these vents let out the most air. It does get hot...eventually, but only first couple sections running for at least an hour. takes calling for heat a whole night for it to fully heat up...

bergensteamguy

Jamie Hall said:

If this is one pipe steam, just increasing the venting on that one radiator is much the simplest approach.

@Jamie Hall , i have a varivalve on there. Do you recommend a different vent on the radiator?

bergensteamguy

Mad Dog_2 said:

Many times you can't fit a drill between the top of the main and the bottom of the subfloor.  Do your best.  Mad Dog 🐕 

@Mad Dog_2 there is plenty of room to tap. probably a foot at least from the top of the main to the ceiling joist.

ethicalpaul

If this chart is accurate, and if your vent is working, and fully opened, then I think there's something else going on (note that a Gorton D is equivalent to a Gorton #1 main vent which vents my entire 30 foot 2" main very nicely). Are you hearing any gurgling or pinging anywhere near this radiator? (this would occur probably later in the heating cycle, after other radiators are fully hot)

If it were me, I'd remove the radiator's vent completely and see what happens at the start of a call for heat (under close supervision). I suspect a water trap is blocking your steam. You'd expect steam to appear at the radiator's vent port to the exclusion of any steam at any other radiator if there is no pooled water blocking it.

By the way, this chart is used as a bragging point by this manufacturer, but that vent is ridiculously oversized for any radiator.

BobC

There has to be a slope in the piping to insure any water can easily find it's way back to the boiler. if water can pool anyplace in the piping it will kill the steam. See if you can lift the whole radiator up to correct any sag, make sure the radiator has some slope so water can find it's way back to the boiler

I'd look for a low spot between the existing main vent and where the steam main turns down to the boiler return. Also look for as low spot between the steam main and the radiator. Aging buildings sag and that sag can cause problems where none existed when the pipes were installed.

Bob

KC_Jones

@bergensteamguy what vents are on the other radiators that are getting steam? As near as I can tell they are stealing the steam that needs to go to the last rad. It is quite possible to increase the venting at the end and not fix the problem, sometimes you need smaller vents.

The main should fill entirely before any radiator in the entire house is getting steam, that last one should be "seeing" the steam at the same time as the rest, if it's not, I say you have too aggressive venting on the other radiators. We need that information to really understand what is going on here.

ethicalpaul

Yeah if they are all open varivalves all bets are off

bergensteamguy

ethicalpaul said:

Yeah if they are all open varivalves all bets are off

@ethicalpaul, yes the last rad is on a varivalve open all the way. The next closer rad/riser is also a varivalue vent. the 3rd to last riser is on a maid o mist #6. Can you elaborate on 'all bets are off?'

Mad Dog_2

Stick with Gortons or Hoffmann.  Mad Dog 🐕 

ethicalpaul

It's what @KC_Jones said just above.

You generally want the main to vent very fast, but the radiators to vent rather slowly.

If you have massive venting on some or all radiators, they will take all the steam (steam will go to where the pressure is lowest). Your other radiators won't get any steam until those very fast-vented radiators fill with steam and their vents close.

But if you start with slow venting on all radiators (like Gorton/Maid O Mist #4, see chart above), and only increase the venting enough to help the slow ones be a little faster (like a #5 or #6 at most) (you have my permission to put as large a vent as you want on this last one that's after the main vent), then you will be OK.

Those varivalves vent so much that it's very hard to control where the steam goes.

So you could still have a sitting water problem with that last one, or it might be that your other radiators are taking all the steam (until they fill up), or some combination.

KC_Jones

bergensteamguy said:

ethicalpaul said:

Yeah if they are all open varivalves all bets are off

@ethicalpaul, yes the last rad is on a varivalve open all the way. The next closer rad/riser is also a varivalue vent. the 3rd to last riser is on a maid o mist #6. Can you elaborate on 'all bets are off?'

You basically have a main vent on that radiator. The one before it is a #6 vent which is also large for what you probably need.

I'd drop both of those to #4, maybe #5 as a starting point and see what happens.

I believe Maid o Mist has one with replaceable orifices so it can be adjusted. @ethicalpaul I think uses those and could comment on if they are worth it.

ethicalpaul

Yes, he said he has a MoM #6 on at least one. The threaded orifices are very easy to swap out for balancing and I have no problem with their performance or longevity (in my short career in steam).

I think a lot of pros don't like them because they are crimped together instead of soldered, but I think that's a kind of confirmation bias. Of course the ones that you get called on to replace, that then give you a fit when trying to remove them are going to stick out in your mind. But there there are many many MoM vents silently and dutifully closing to steam every winter day.

BobC

I agree Heatimer air vents can cause all kinds of mischief and should not be widely used on a system, I replaced all my air vents with Maid O Mists a decade ago and all of them are still in use. Several were the ones that have the multiple orifices and have kept the surplus orifices - might come in handy. Back then they were a very good vent that was a lot cheaper than Gorton with the added feature of the replacable orifices. I have not bought one since so I van't speak of current production.

Bob

Mad Dog_2

Nothing against Heatimer..great Company, well built Air vents...BUT..I've never seen the adjustment work AND they will gush steam condensate like Niagara Falls if the Steam is not perfect.  Gorton and Hoffman for me...thats it!  Mad Dog 🐕 

bergensteamguy

Mad Dog_2 said:

Yes...Main vent should be PAST the last take off.  Cutting in a tee 15" back from the vertical drop in to the wet Return is ideal. Sometimes, this is not practical because of space, logistics, asbestos and I'm happy to get one in anywhere in the Vicinity.  If rather drill & tap a Cast Iron fitting for the beef & girth, but sometimes I've got to tap a pipe. With Low pressure steam (2 psi & below) its not an issue. Tap atleast  a 1/2 " thread if you can and pipe it up as high as you can just under the floor boards.  Pitch your piping so that you don't Ship water up in to the Gorton # 2.   Good luck  send pics  Mad Dog 

@Mad Dog_2 , if i were to put in a main vent 15 inches before the end of the main, what is the best approach for putting in a tee? I.e. would it be to cut both pipes put in the tee and join them with a union? That is the only logical way i can think of.. not a pro though.

Mad Dog_2

That's alot of work and usually, not really necessary.  Can you post a good picture of the area.  With Low Pressure Steam systems, you can get away with a Drill & Tap even a Saddle.Mad Dog 🐕 

bergensteamguy

Mad Dog_2 said:

That's alot of work and usually, not really necessary.  Can you post a good picture of the area.  With Low Pressure Steam systems, you can get away with a Drill & Tap even a Saddle.Mad Dog 🐕 

@Mad Dog_2 see pictures below. The one picture is the end of the main going into the return. The other is a full picture where the existing main vent is. the last picture (circled in yellow) is the return from the other main, which I was suggested to also put in venting. My mains split into two. Both returns connect on the wet return below.

ethicalpaul

That location is good. I agree with Mad Dog, drill and tap or saddle won't have any trouble with your hopefully less than 1 psi.

If that fails for some reason you can always cut it out and go with the tee, union, and 3 nipples.

They really should have put a tee here instead of the elbow when they piped it:




Check this horizontal section to make sure it is pitching toward the main (and definitely not the other way):

bergensteamguy

@ethicalpaul, is there a specific tap I should use for black steel piping? I have not tapped anything in a long time, but assuming different taps have different tap sizes?

ethicalpaul

Since you already have main venting just upstream, you can go small. That way if you mess it up you can go to the next size up

You need NPT threads and if it were me I'd go with 1/8". Then you can use a straight (not 90 degree) "D" capacity vent which is equivalent size to a #1 main vent. I'll get you some links and put them in this post momentarily...

Here is a drill and tap set. No doubt someone will say "that's Chinese garbage, get Grainger instead!" But this isn't a moon mission, this is a small hole in a pipe, this will be fine:

https://www.amazon.com/Century-Drill-Tool-93201-Combo/dp/B0797JWQ1R/ref=sr_1_5?crid=1SRW49FXO2XFH&keywords=1/8"+npt+tap&qid=1696598985&sprefix=1/8+npt+tap,aps,62&sr=8-5&th=1

Here's your vent in Gorton. They have gone up about 30% in the last few years

https://www.supplyhouse.com/Gorton-GDS8-Gorton-No-D-1-8-Straight-Vapor-Equalizing-Valve-3539000-p

If it were me, I'd go with Maid O Mist, it's the same design as Gorton (in fact, Jacobus MoM were the original of this design I believe) and it's less than 1/2 the $$. I use these on all my radiators.

https://www.supplyhouse.com/Jacobus-Maid-O-Mist-JDS8-D-1-8-Straight-Air-Valve-7861000-p

You can actually get any capacity Maid O Mist vent because then you just unscrew and remove the orifice on top and it will magically become a "D" capacity.

Put a few inch long 1/8" nipple into the tapped hole (might as well go with brass), then a coupling (again, brass, readily available from SupplyHouse), then the vent.

https://www.supplyhouse.com/Everflow-NPBR1830-1-8-x-3-Brass-Nipple

https://www.supplyhouse.com/Bluefin-BRC018-1-8-FIP-Brass-Coupling-Lead-Free

bergensteamguy

thank you @ethicalpaul

ethicalpaul

If you run into trouble drop me a PM, I live in the county next to yours

ethicalpaul

Oh and to possibly start up some controversy in this thread (it's Friday ) you have a nice elbow setup on your existing main vent, but it's not necessary here, or even there. It's especially not necessary mid-main like yours is, but it's also not necessary at the elbow that sends the main down to the wet return. Of course, it is necessary if you want multiple main vents, but 90% of systems don't IMHO.

The "slug of water" idea (that this massive wall of water comes barreling down your main) is a myth. At the beginning of steam production, there is a tiny rivulet of water. Within a few minutes it will become a slightly larger trickle of water. It's all very gentle and calm. I know because I put windows on my main pipe.

The only time there is any kind of violent water flow in a main is if your near-boiler piping is bad and your water quality is bad. Then the boiler will empty itself into your main when it starts boiling, and you have more problems than can be solved with two elbows under your main vent.

question

I had a plumber master vent the risers. They taped the riser pipe before the shutoff valve of the radiator with a Gorton #2. This way the entire riser vents quickly.

Mad Dog_2

Yeah..I agree with Paul.  If your going to use it once, you don't need A Vermont-American Quality Tap. 1/8" is better than nothing, but I'd go atleast 3/8" in to a 2" Steam main. Plenty of meat 🍖. Too small is going to really restrict your C.F. of air flow out of the main vent.  Plenty of meat .   Use a little WD-40 as you drill & tap.  Mad Dog 🐕 

bergensteamguy

thank you @ethicalpaul

Mad Dog_2 said:

Yeah..I agree with Paul.  If your going to use it once, you don't need A Vermont-American Quality Tap. 1/8" is better than nothing, but I'd go atleast 3/8" in to a 2" Steam main. Plenty of meat 🍖. Too small is going to really restrict your C.F. of air flow out of the main vent.  Plenty of meat .   Use a little WD-40 as you drill & tap.  Mad Dog 🐕 

@Mad Dog_2 , i plan to tap the 2inch main with a 1/2 and stick on a gorton #2. For the other main, I measured the cubic feet of air. A gorton #D vent would be more than sufficient to vent a 12FT main. So I plan to tap a 1/8 hole on that 1 and 1/4 inch pipe. This will give me 3 main vents in total (2 Gorton #2s and 1 Gorton #D), as opposed to having only one for the entire system.

bergensteamguy

I will post pictures and update everyone on the status of the new vents and venting.

mattmia2

Use cutting oil. It makes a huge difference over oils without extreme pressure additives.

bergensteamguy

mattmia2 said:

Use cutting oil. It makes a huge difference over oils without extreme pressure additives.

Thanks @mattmia2 , I did order some off Amazon. I feel it should be efficient enough for the two holes I need to tap.