Single Pipe Steam Main Air Vents

northeastconfederate

Someone suggested I get a copy of "The Lost Art of Steam Heating." There is a new version, called "The Lost Art of Steam Heating Revisited." Doe the first version need to be read first? Or will "Revisited" cover all the subject matter in the first version and then some???? I know I'm asking a million questions...

I just ordered a pair of Big Mouth vents. I'll make a pipe and fittings list tomorrow - it's supposed to be near 60 the next couple of days (it was 17 this morning...). Maybe I can get this near boiler piping corrected.

KC_Jones

I attached a picture of the manual. The second riser is not optional on the size boiler you have. Look at the chart, you have an IN8 so it shows that as required. You need to make it look like this picture.

Erin Holohan Haskell

northeastconfederate said:

Someone suggested I get a copy of "The Lost Art of Steam Heating." There is a new version, called "The Lost Art of Steam Heating Revisited." Doe the first version need to be read first? Or will "Revisited" cover all the subject matter in the first version and then some???? I know I'm asking a million questions...

Revisited covers everything in the first book and more.

northeastconfederate

> @KC_Jones said:
> I attached a picture of the manual. The second riser is not optional on the size boiler you have. Look at the chart, you have an IN8 so it shows that as required. You need to make it look like this picture."

Thanks for that. According to that drawing, the mains need to be 3" also. Dammit.

Steamhead

Erin Holohan Haskell said:

northeastconfederate said:

Someone suggested I get a copy of "The Lost Art of Steam Heating." There is a new version, called "The Lost Art of Steam Heating Revisited." Doe the first version need to be read first? Or will "Revisited" cover all the subject matter in the first version and then some???? I know I'm asking a million questions...

Revisited covers everything in the first book and more.

@northeastconfederate , this book is highly recommended. Also, where are you located?

northeastconfederate

> @Steamhead said:
> (Quote)
> @northeastconfederate , this book is highly recommended. Also, where are you located?"

I'll get a copy of it.

Located in Central NJ

Jamie Hall

On the pressuretrol. There are two flavours, but if yours is the pretty standardl blue grey box with one visible scale, it's "additive". That is, the visible scale setting is the cutin pressure. Inside it is a differential wheel, which is added to the cutin pressure to get the cutout. If your's is set to 5 psi on the outside scale and 1.5 on the inside wheel, your cutout pressure is 6.5 psi and the cutin 5.0 psi.

Which is way too high, and will destroy your vents in short order, not to mention causing valves to leak and other mischief. Set the outer scale to just above the 0.5 mark and the inner wheel to 1. Your system will be much happier -- and cheaper to run.

KC_Jones

I would not rush the near boiler piping. As someone who did his own boiler replacement it takes time. I had a detailed 3D model, all the pre cut pipe lengths and it still took me days. Pros can go faster, but I wouldn’t plan on trying to knock it out in a day. I’m kind of picky, but I spent several weekends and the weeks between (evenings after work) working on my piping.

On the 3” mains, they show only one main, you have 2. 2 2” pipes is equivalent to a single 3” pipe, so I would not even think about touching the mains other than tying them in to the header individually.

northeastconfederate

> @KC_Jones said:
> I would not rush the near boiler piping. As someone who did his own boiler replacement it takes time. I had a detailed 3D model, all the pre cut pipe lengths and it still took me days. Pros can go faster, but I wouldn’t plan on trying to knock it out in a day. I’m kind of picky, but I spent several weekends and the weeks between (evenings after work) working on my piping.
>
> On the 3” mains, they show only one main, you have 2. 2 2” pipes is equivalent to a single 3” pipe, so I would not even think about touching the mains other than tying them in to the header individually."

Oh, good. That's a relief. I will make a fittings list and measure for pipe for the near boiler piping. Once I get the materials there I'll see about re-doing the header. I can probably hire a plumber I work with sometimes (I'm a contractor) to work with me. Between us, I'm sure we could get that header done in a day.

Regarding Pressuretrol settings: I'm sure the operation manual will give optimum settings for that unit, right? 0.5 psi seems pretty low. Is this really what I want? The lowest setting possible?

It's funny: I'm a licensed high pressure boiler operator (so-called Stationary Engineer). Worked in power plants for years. So I'm accustomed to 1,000 psi and up, and flow rates of 700KPPH. But none of that - or very little - transfers to this low pressure stuff.

KC_Jones

You need enough pressure to overcome the resistance of the piping, other than that pressure does nothing in a heating system.

Pressure means there is something slowing the steam from moving. The boiler, if disconnected, would just make steam all day and show zero pressure. So once you hook it up to the system it gets resistance. The only resistance you really want coming into play is the piping, not venting. So let it run as free as possible.

The pressuretrol is a safety device not an operating control. The problem is many boilers are oversized and it forces the pressurtrol to become an operating control. It’s better to have a properly sized boiler and good venting. My system has a vaporstat set to 4 ounces for my low fire and another set to 8 ounces to shut the burner down. I never hit the low fire. I get steam to all the rads (warm boiler) 3 minutes after burner start.

If you want to know how oversized the boiler is, we can assist with the EDR calculations, they aren’t too hard. It might be a worthwhile exercise to get a reality check on how much work is worth putting into that boiler.

Do you know how old it is?

northeastconfederate

How old: 2008 is what the label says.

KC_Jones

If you repipe, I’d start with getting the plug out of the second tapping on the boiler, it’s probably not going to be fun.

Some on here recommend a good impact gun and plenty of penetrating oil.

Also, if it’s not installed, I’d try and get a skim tapping in there. With all the new piping your going to need to skim. Without that the boiler does all kinds of fun stuff making you think you screwed up. I think Burnham calls the skim a surface blow off or something like that.

gfrbrookline

You want to eliminate the 2" header. Have 2 2" risers coming out of the boiler attached to the 3" header. There should also be a drop that leads back down the the boiler into a Hartford loop to the right of @KC_Jones right blue circle. The 3" header needs to pitched to drain towards the right circle into the hartford loop o the steam pressure is equalized.

northeastconfederate

> @KC_Jones said:
> If you repipe, I’d start with getting the plug out of the second tapping on the boiler, it’s probably not going to be fun.
>
> Some on here recommend a good impact gun and plenty of penetrating oil.
>
> Also, if it’s not installed, I’d try and get a skim tapping in there. With all the new piping your going to need to skim. Without that the boiler does all kinds of fun stuff making you think you screwed up. I think Burnham calls the skim a surface blow off or something like that.

Surface blowdown. It removes the scum that floats on top of the water. In power boilers, chemicals are added - phosphates - which not only raise the pH of the water, but cause the solids which remain after the water flashes to steam to form a non-adhering sludge. The blowdown (allowing some water to leave the boiler) removes this sludge, preventing buildup.

This boiler could use a blowdown. I found a LOT of sludge in the condensate piping when I replaced a few pieces of that. In power generation, the blowdown water goes to a blowdown tank. Then elsewhere to either be used or disposed of. Where would you send it in a residence like this??

northeastconfederate

> @gfrbrookline said:
> You want to eliminate the 2" header. Have 2 2" risers coming out of the boiler attached to the 3" header. There should also be a drop that leads back down the the boiler into a Hartford loop to the right of @KC_Jones right blue circle. The 3" header needs to pitched to drain towards the right circle into the hartford loop o the steam pressure is equalized.

Yup, I see that in the drawing KC posted. Thanks for noting the proper pitch toward the Hartford loop - Not sure I'd have gotten that right.

KC_Jones

Anything that comes out of my boiler goes into the sewer. Skimming in this case is simply for the oils left over from manufacturing. They float, you skim them off very very slowly. Simple, but time consuming process.

Not many use water treatment, but I’m an advocate for it. There are a couple options one is steamaster tablets, but they have gotten really hard to source. The other is 8 way boiler treatment which is supposed to be pretty much the same as steamaster.

This isn’t like what you are used to, blow downs aren’t done often, I’ve done 1 in 5 years. I also run copper wet returns which seem to make a huge difference in system cleanliness. Also if you want to do a blowdown you will need to add king valves and a valve on the Hartford loop. So you can isolate the boiler from the system to build pressure. Steam heating systems are open to atmosphere.

Steamhead

northeastconfederate said:

Located in Central NJ

There are some good Steam Men in that area. @Dave0176 , @EzzyT , @clammy , @JohnNY are all good.

northeastconfederate

> @Steamhead said:
> (Quote)
> There are some good Steam Men in that area. @Dave0176 , @EzzyT , @clammy , @JohnNY are all good.

Good to know, thanx for the info.

I just ordered a copy of The Lost Art...

I also ordered a pair of Big Mouth vents, one for each main. I will be going to the building today to make a list of fittings and pipe to correct the header piping. Not sure when I'm going to dig into that. I had major shoulder surgery 2 weeks ago, so slinging pipe wrenches is not in my immediate future. However, I will have one of my employees install the Big Mouth vents.

Meanwhile, should I adjust the pressure setting of this boiler down as it is now? KC mentioned that the high pressure setting could be an attempt to overcome the poor piping and inadequate venting. If I adjust it down before correcting those issues, will I be creating another problem?

ethicalpaul

Lowering the pressure should always be the first thing. You want to be there anyway and you don't want to "fix" other things in terms of that higher pressure.

KC_Jones

northeastconfederate said:

Meanwhile, should I adjust the pressure setting of this boiler down as it is now? KC mentioned that the high pressure setting could be an attempt to overcome the poor piping and inadequate venting. If I adjust it down before correcting those issues, will I be creating another problem?

The only way to know is to try it. As I said if you adjust it down and the boiler cycles so often that you never get the steam where it needs to be, you may just have to keep the pressure up until the system can be corrected. If it was mine I would adjust it down and then watch it run for a couple cycles of the thermostat then decide.

northeastconfederate

I got a copy of Steam Heating Revisited and started reading. Very informative. I read with great interest the info about "Dimension A" - the height of the return above the water line - and how that dimension relates to boiler pressure.

"Dimension A" here is 23"; 5" less than what is needed for condensate to overcome 1psig boiler pressure and get back in there. From what I read, this must be why a check valve was installed. Well, that plus the too-high boiler pressure, which could - and probably did - push water back up into that dry return.

I also had a couple of Big Mouth vents delivered, one for each main. I installed one of them in the main which is fairly easily accessible. The other main is going to have to wait until I can get some help. I had shoulder surgery 2 weeks ago and am not in shape to be crawling around in the crawlspace.

I also turned the Pressuretrol - which is subtractive, according to what I read - down from 5psig to 3psig. I left the differential alone at 1.5. I can't remember exactly what the book said about proper pressuretrol settings for a subtractive setup.

We'll see what happens with the reduced pressure.

Back to the vents for a sec: I had 2 Hoffman 75's, one of which was (the first one in line) spitting steam and condensate. I now realize that was probably in large part due to the pressure being too high. Though it says max pressure 15psig. I removed that vent and replaced it with a Big Mouth vent. The 2nd Hoffman #75 is about 16" downstream of the new Big Mouth. I left it there. Any reason I should remove and plug it?

JUGHNE

Are there any live termites still living in the pile of wood on the floor behind the boiler?

northeastconfederate

No. And yes, I realize the place is a mess. You're going to have to cut me a break. Two of the 4 foundation walls in the larger section of basement collapsed in May. I've been a little bit busy keeping the house from falling down, overhauling the entire plumbing system, since it was either attached to or in the way of rebuilding one of the two walls that caved in, rebuilding the foundation, replacing the front porch that was in frontof the same wall... I could go on. Tryst me, clean up is on my long list of things to do.

Got any input on what I asked about???

dennis53

It's hard to tell from the photos, but it looks like you have a radiator run out between your two vent locations on the accessible main. If that is the case, you should move all your vents to that vent location that is downstream of the last radiator run out and plug the vent location before the run out.
Ideally, you could have a Big Mouth and a #75 on each main.
Sorry to hear about your shoulder and the foundation/plumbing problems. When it rains, it pours.
Dennis

gfrbrookline

I would set your pressuretrol main between the 2 and the notch below and between 1 and .5 on the differential. This will let your system run between 1.5 cut out and .75 cut in which should make your vents much happier. A residential system should not be run above 2psi.

northeastconfederate

> @dennis53 said:
> It's hard to tell from the photos, but it looks like you have a radiator run out between your two vent locations on the accessible main. If that is the case, you should move all your vents to that vent location that is downstream of the last radiator run out and plug the vent location before the run out.
> Ideally, you could have a Big Mouth and a #75 on each main.
> Sorry to hear about your shoulder and the foundation/plumbing problems. When it rains, it pours.
> Dennis

Dennis, you're right. I was thinking last night that I'd better go back and check, because I thought that radiator runout might be after that vent. It definitely is. For starters, I'll move the Big Mouth to the end of the line, where it should be. As for the #75, maybe I can make a "tree" and include both the Big Mouth and the Hoffman #75 that way. No reason that won't work, right?

Thx for the well wishes regarding my shoulder and the building's issues. All are on the "up" side, now. Just a matter of time and perseverance to keep making steady progress.

northeastconfederate

> @gfrbrookline said:
> I would set your pressuretrol main between the 2 and the notch below and between 1 and .5 on the differential. This will let your system run between 1.5 cut out and .75 cut in which should make your vents much happier. A residential system should not be run above 2psi."

Ok, so set the cutout (the Main) at 1.5 and the differential at .75.

I'm a little concerned about changing things too much before getting the near boiler piping straightened out. I'm wondering if the high pressure setting was made to compensate for issues caused by the incorrect piping. Am I right to be worried about this?

acwagner

You are probably right that someone in the past raise the pressure thinking it would address their issues.

Lowering the pressure should have no negative impact at all. With a system with multiple issues it's sometimes hard to see its positive effect.

I would keep all the main vents in addition to your new big mouths. You really can't over vent a main. You can put multiple vents on one opening. They call it making an "antler". You can search for the term on this site and see multiple examples.

I would avoid putting a vent on the end of the line. That location is prone to damage from water hammer.

northeastconfederate

acwagner said:

You are probably right that someone in the past raise the pressure thinking it would address their issues.

Lowering the pressure should have no negative impact at all. With a system with multiple issues it's sometimes hard to see its positive effect.

I would keep all the main vents in addition to your new big mouths. You really can't over vent a main. You can put multiple vents on one opening. They call it making an "antler". You can search for the term on this site and see multiple examples.

I would avoid putting a vent on the end of the line. That location is prone to damage from water hammer.

Ok, thanks for the comment that you can't over vent a main.

Avoiding putting a vent on the end of the line: But the vent needs to be downstream of the last radiator runout, right? It's hard to see in the picture because the lighting is so poor. But take a look at the picture I posted of the two Hoffman #75 vents installed in the system. The one in the foreground is upstream of the last runout; the one in the (dark) background is after it. This is the location I'm thinking of as the "end of the line," and is where I'm thinking of creating an antler. Or at least relocating the Big Mouth vent to this location. Then plugging the other vent location since it's upstream of the last radiator runout.

I'll get the pressure lowered to the recommended 1.5 cutout and .75 cutin, possibly today. Today is probably a good day to mess with the vents, too, since it's relatively warm. The boiler won't be running much today, so I won't have to wait long for the system to cool off. Or piss off my tenants by making heat unavailable while the boiler is shut down.

northeastconfederate

I downloaded the I&O manual for this boiler and am studying the piping requirements, which KC posted earlier in this thread. Just to reiterate and make sure I understand clearly: Each of the two mains should have their own connection to the 3" header (currently they're teed). Right? The other important question is: since I have two 2" mains, the required 3" main diameter is met. Two 2" pipes exceed the capacity of a single 3" pipe. So I'm good there, right? I know this was covered earlier in this thread, just want to make sure I have it clearly.

I am working my way through The Lost Art of Steam Heating Revisited, but haven't gotten to any kind of sizing formulas, yet. It's a huge book, and I'm only about 60 pages in so far.

northeastconfederate

It's funny. Well, not really. Two years ago, I hired a plumbing contractor who claimed to have thorough knowledge of single pipe steam heating systems to come look the system over, evaluate, recommend, and perform any required routine maintenance. It didn't come cheap. The guy who showed up, an employee of the company, was a nice enough guy, and also a mechanical engineer (I found out during conversation). He made sure the burner was clean, that all nozzles fired, showed me what he was looking at and where so that I could do it myself going forward. Nice enough guy, and well intentioned, it seems. But that was it. He pointed out the Hartford loop and explained that it was a required safety feature. Seemed to know what he was looking at. I pointed out the rusty main vents and asked about replacing them and the radiator vents, and his only comment was that I could save an awful lot of money doing all that myself. Doubtless that's true. But there was no mention of the near boiler piping being wrong - not even the bushed reduction in the horizontal header or the teed mains. Or the one main vent being upstream of the last runout. He explained the pressuretrol operation, but never said anything about the pressure being way too high for a residential heating application. All things that were immediately pointed out here.

I hired this outfit because I knew I didn't know what I was looking at, nor where to find out. And, I had my hands plenty full with other things. So I wanted someone qualified and knowledgeable to handle it.

As with so many other things in life, I have found that one really must be knowledgeable about one's own equipment and be one's own advocate. Obviously, this cat didn't know $hit. But he didn't know that he didn't know $hit.

Glad I found this forum and that I'm learning about this system. Seems I'll be able to increase my tenants' comfort and save myself a pile of money in heating bills at the same time. Not to mention increasing the value of this property, as properties like this are valuated on the income method. Reducing operating costs will have a big impact on that.

JUGHNE

Do you have access in your basement to any of the dry returns before they become wet returns?

If so it might be possible to have the air venting there, accessible and visible, without the grief of the crawl space.

As far as the vent location just ahead of the last runout, you would be venting the main to that point. The last rad would have to vent the rest thru it's vent. For that short of a distance not a big deal IMO.

coelcanth

northeastconfederate said:

Avoiding putting a vent on the end of the line: But the vent needs to be downstream of the last radiator runout, right?

i think he just meant don't install the vent directly into a tee at the end of the main.. on an antler at the end of the line would be fine.

anyway, my big mouth vents are installed directly into tees at the very ends of my mains (same locations as the original vents for 100 years).
i can't move them or even build antlers because of clearance issues
but i haven't noticed any negative effects, maybe because my system doesn't really have water hammer problems.

acwagner

Here's a diagram that shows the best practice for main vent location to protect it from water hammer. You are right, keeping the main vent just after the last riser is best. Hard to tell from your photo, but it looks like the main continues after the second vent location, or does it drop to become a wet return?

northeastconfederate

Well, I took another good look at the vents at the end of the steam main today. I discovered another problem, which is the transition from the steam main to the condensate return. It's a bushing that goes from the 2" main to the 1-1/4" dry return. No doubt that traps water at the end of the main.

I didn't know the vent being so close to the end of the line was going to be an issue until you posted the "right vs. wrong" drawings.

You're right, there's another main vent about 16" downstream of the first. Immediately following the tee with the 2nd vent is a bushing down to 1-1/4, then an elbow going sideways, not down. Picture of that mess attached.

Now I don't know what to do with these vents. I was going to move the big mouth vent to the location shown in the picture, which is downstream of the last runout. But maybe I should leave it where it is, just before the last runout. I reposted the dark photo of the two main vents. I circled both of them, because the 2nd one (farthest downstream) is hard to see. Also in that circle around the 2nd vent is the last runout. I should take a picture of the return back there as well. I won't have a chance to do that until Monday, but I will take one and post it. Seems to me that I can't really correct this vent placement without some pretty major rearranging back there.

northeastconfederate

I just realized I didn't really answer the question about a wet return: I believe it's a dry return. It's a very long run from back there in that corner to the boiler. It's about 50 feet of pipe, maybe a little bit more than that. About midway along that run of pipe it reaches the level of 28" above the water line.

Considering how F-ed up the piping is in places, I'm surprised that I don't have any water hammer complaints. A year and a half ago, I repaired the floor under a radiator whose inlet valve had been leaking for a long time. The radiator was actually falling through the floorboards. This resulted in that runout having a negative pitch, so water would get trapped in that pipe. When I fixed the floor and raised the radiator back up where it belonged, that also fixed the pipe's pitch. One of the tenants said that I fixed the "banging" after that.

I turned the pressuretrol down to 1.5 and the differential down to .75 today. It was a relatively warm day here, so the boiler wasn't running very much; most of the steam pipes were actually cool to the touch. So, I don't know what effect the adjustment had yet. We'll see what happens with that.

acwagner

That bushed down main-to-dry return connection is definitely holding water, which could cause all kinds of havoc on your main vents.

You might be able to correct it by getting an eccentric reducer coupling like this:

https://www.grainger.com/product/ANVIL-Eccentric-Reducer-Coupling-4KVZ2

They are expensive, but could avoid a lot of repiping and entirely redoing the dry return.

northeastconfederate

Yep, that eccentric reducer looks like just the ticket. Holy $HIT, that's an expensive fitting! But definitely would save on a lot of repiping. I still would have to re-do some of it to get the minimum 15" between the vent and the end of the main.

It turns out I do have a couple of pictures of the dry return at that end of the building. See attached pix. The elbow and bushing we're talking about is just out of view to the right in the first picture.

acwagner

That return looks pretty new. It also looks suspiciously close to the boiler water line. What is the height of that return piping relative to the boiler water level?

Jamie Hall

I'm concerned about that low return, too. As the boiler builds pressure, it's quite possible that water can back into it -- and it could hold a surprising amount of water. Can you raise it and then drop it down at the boiler? Dry returns don't need all that much slope, so long as it is constant.