Bad near-boiler piping (Previously: Was this once a main vent?)

espire · November 2023

Happy Thanksgiving!
There are two steam mains in my house.
One main goes across the front of the house in the basement, with a vent on the end just before dropping down to the return. That vent almost definitely needs to be replaced but I haven't gotten to it yet because the main goes along a narrow alcove between the foundation and the wall of the finished part of the basement.
The second main goes around the circumference of the rest of the house, and then finally drops into a return in a small utility room near the boiler room. There is no vent on this main that I can find. However, there is a short capped off pipe just before it dips for the return. It seems to me like it would be a decent spot for a main vent. Is it likely that it used to be a vent?
Now, even though this main goes down the right side of my house and then across and down the left side, it actually only feeds radiators on the right side. The left side of the house used to have a few radiators, but they've been removed (not by me). In that case, is it even a good idea to put a vent here, seeing as it would result in filling the second half of the main with steam that has no radiator to go to?
Right now the second half of this main generally doesn't get hot; I assume that even though condensation is hopefully making its way along it, there is a pocket of dry air that is squeezed by the steam but has nowhere to go.

Main going from left to right and then dips down on its way back to boiler

Looks like a Maid-o-Mist #1 would fit into this coupling
Thanks as always

EBEBRATT-Ed · November 2023

Don't think so. That tee and nipple line up with the pipe directly above it and especially with the union in that pipe I am pretty sure that pipe was connected to that tee.

EdTheHeaterMan · November 2023

That is possible @EBEBRATT-Ed, there is also the possibility that another steam take off to a different radiator could have been there. Since it is 45°, I doubt it was originally a vent take off. More likely a radiator takeoff.

But There can never be too many vents on a system. Just a waste of time and vents with diminishing returns as you add more vents. Since there are no vents in that area, and it appears to be the end of the main, I would do it! Will it fit on top of that pipe nipple with a coupling? That would be better. If not, perhaps a 2" long nipple and a coupling.

pedmec · November 2023

Look further down the return on the other side of the wall. Normal location for a main vent would be just before it drops down into the wet return. Like Ed said, a tee at a 45 normally indicates a supply to a radiator.

Steamhead · November 2023

You'd need to pipe over from that other steam line above it, but it's as good a main vent location as any.

How long is the main, and what pipe size?

ethicalpaul · November 2023

Just for fun, Ed, I think you can have too many main vents.

each vent has to be heated to close. That takes time and steam. If you have extra vents, you unnecessarily delay steam getting to the radiators.

Waher · November 2023

If vents only pass air and not steam, why would having extra vents getting air out of the way of steam delay getting steam to radiators?

Steamhead · November 2023

They would actually speed up steam reaching the radiators.

ethicalpaul · November 2023

Unless you had extra ones, then the steam has to heat them up for no reason, which takes time.

espire · November 2023

Thanks everybody for your insightful comments!

@pedmec takes the prize here. Indeed the main vent was in the boiler room just before the vertical drop to the wet return. It was probably easy to access before the basement was finished, now it should still be possible but more of a challenge.

Considering the end of the main is usually not so hot and how worn vent looks, there's just about 0% chance that it still works right? For curiosity's sake, can anybody identify what model/manufacturer this vent is? I'll probably replace it with that MoM #1 for now.

So, my original "vent" location was probably actually a radiator? Now it's underneath a part of the kitchen with no room for radiators. But when the house was built in 1931 perhaps the kitchen looked very different. It would be a lot of fun to see how the house changed over the decades but that's probably lost to history...

ethicalpaul · November 2023

I agree with you to replace it, good job finding it!

gfrbrookline · November 2023

don't waist your money on a MOM get a gordon No. 1 you might even benefit from an antler and a few depending on the size and length of your main. What are your dimensions?

Steamhead · November 2023

@espire , that's an old Trane vent. It might be original to the system.

How long is the steam main, and what pipe size?

espire · February 5

An update: In the end, I had Pipe Doctor AKA Mikey Pipes come to look at a number of things around the house, and in the meantime I had him install the main vent. Better him than me damaging something on the steam main in the middle of the heating season

He felt pretty strongly that despite my having found the old vent in the wall, the 3/4" takeoff was too small to have been anything but another vent once in the past. It's a good spot for a main anyway, since there is a dropoff to the dry return right after. I supplied him with a Gorton #2 that I had ordered and away we went. Too bad about the pipe wrench on the vent's throat, but it's not the end of the world! We also put a Gorton #1 on the shorter main for the front wall of the house.

You might notice a drop of water hanging onto the vent. There seems to be a fair amount of water coming out of it -- the last few days there has usually been more than a drop of water on the floor beneath it. Is this expected, considering how much steam it will release before getting hot enough to close? We do have problems with the mains banging near the boilers, which Mike suspects is a clogged wet return. I'll be surprised if the water is backed up all the way to here but maybe that's indeed what is going on.

KC_Jones · February 5

There shouldn’t be water there in quantity to come out the vent, and no steam should ever come out. If it does it’s a sign of other issues. Bad boiler piping, incorrect pipe pitch. A clogged return would be my last thought as you’d see other signs of that, like shutting down on low water then overfilling later.

espire · February 6

Thanks KC! It makes sense that a clogged return would cause water level chaos. My auto-feeder is filling less than a gallon per week which seems within acceptable limits.

The wet returns probably are at least partially clogged, simply on account of their being very old and having no cleanout valves. They are often quite cool in the middle section far from both the boiler and the dry return. But considering the multiple-inch drop right after the main vent seen in the top photo in the thread, it would have to be a really bad clog to back up all the way to the vent.

I'll have to take a level to the pipes near the vent and see how their pitch is. It could be there has been standing water in that area for a long time, and without the vent, steam was never able to make it that far along the pipe.

KC_Jones · February 6

If your auto feeder is feeding weekly that’s excessive. You’re either leaking a ton of steam, a wet return has a hole, or the boiler has a hole. You shouldn’t be feeding more than once a month, if that.

What does the boiler piping look like?

espire · February 6

You are kind to offer to take a look at the near-boiler piping, so I'll post a few photos:

Front and right of the boiler. The front-of-house main leads away from the right side, which seems to be simpler and less problematic. My understanding is that the header is uncomfortably close to the boiler, though perhaps just barely in spec.

Left side of the boiler. You can see the back-of-house main leading away in the upper left. Upper right is just a gas line. I believe most of the banging that has occurred over the last month was on this section of the main near the boiler, usually just around when the pressuretrol cuts out.

Continuation of the back-of-house main. Here things get unfortunately weird. You can see that the main immediately drops to a relatively new dry return. This is because its visible continuation to the left along the wall is actually a similarly newer branch leading to the attic -- it is the vertical pipe in my earlier photo today. The "main" part of this main actually goes up a bit then through the wall, and its own dry return is seen running next to a joist to the rightmost drop in the photo -- this completes the loop on which the Gorton #2 was placed.

espire · February 6

As far as auto feed rates go, I should note that there was a fairly quick leak in a radiator union that I got fixed just before the most recent water feed. That fill was about a week and a half ago, so hopefully the feed rate is actually less than weekly now. There's also a radiator in the attic with a pinhole leak, that I recently shut off while I find the time to attempt to get a few more years out of it with JB Weld.

...We recently moved in here and there are quite a few issues that I've been trying to improve... I'm just glad the boiler is able to keep us warm!

KC_Jones · February 6

What model Independence is that? I’m curious about the size so I can verify recommended piping in the manual.

Sylvain · February 6

- Gas, water-feed , hartford loop and return are on the left side.
What is the pipe with a closed ball valve on the right side? (connected to the boiler below the safety valve connection).

- Souldn't the rectangular opening in the chimney be closed (with a removable plate)?

espire · February 6

@KC_Jones, it's an IN7I. I believe it's oversized for our heating load, but that's what was here when we moved in.

@Sylvain, very observant! That's the return for a hydronic baseboard loop to heat the finished part of the basement. No heat exchanger or blending of boiler water with already-circulated water, just a Taco circulator out of the mud leg and back in the right side. The pump is just controlled by a light switch instead of a separate basement circulator thermostat and water thermostat to run the boiler up to hydronic heating temps, so it's not too useful as is. When switched on the circulator makes a terrible noise, so at best the line is clogged, and more likely the motor is shot.

You're probably right about the chimney cleanout, especially if it continues to join with the boiler and water heater exhaust. I'll take a look at it.

KC_Jones · February 6

I was afraid it was an IN7.

Ok, it's piped incorrectly, and I'd bet that is a big part of the problem. That boiler is supposed to use both risers in 2" and into a 3" header. You have a single 2" riser into a 2" header, in addition the first horizontal section of the header is pitched towards the boiler, which makes the wrong, worse. See below screenshot of the manual showing what I'm talking about. So, you had Mikey Pipes in and he didn't notice any of this? Interesting.

By the way, I'm just a homeowner like you and I got fed up with contractors not knowing what they are doing, so I educated myself and ended up installing my own boiler.

You're boiler needs re-piped, I don't see you being able to get things working even kind right until that's done. It's sad to me because there is a picture right in the manual of how to do it, and the installer of that boiler didn't bother to look.

dabrakeman · February 6

Did you make sure that the Gorton #2 that was put in was working (i.e. not stuck open)?

espire · February 6

KC_Jones said:
You're boiler needs re-piped, I don't see you being able to get things working even kind right until that's done.

Aha, I can see the issue now and that's too bad. I imagine that if Mike was doing the piping himself, he'd follow the manual and use two risers. He did mention that if he was in such a constrained spice he would use a drop header to reduce water getting into the mains. But it's true that he jumped to the issue being a clogged wet return before investigating other issues.
The single riser might explain banging in the mains near the boiler, but I don't think it would explain water getting into the main vent all the way at the end of the main, right? In that case I should still check the pitch of the mains there.

KC_Jones said:
By the way, I'm just a homeowner like you and I got fed up with contractors not knowing what they are doing, so I educated myself and ended up installing my own boiler.

I looked at the photos of your own boiler installation and it looks fantastic!

dabrakeman said:
Did you make sure that the Gorton #2 that was put in was working (i.e. not stuck open)?

Thanks -- when I'm watching it, it works really well, huffing and puffing air until the main is filled with steam and then it goes silent. But occasionally I hear it gurgling, as if there are some water drops dancing around inside it. I have never actually seen water coming out.

KC_Jones · February 6

If the near boiler piping is getting water in the main, the only way it gets back to the boiler is to run all the way to the end of the main, so yes if it's bad enough, it could indeed be wreaking havoc all over the system.

Remember, the only water that should be out in the pipes is the condensate created from the steam distribution. The water from the boiler should never go up into the main. With a single 2" and 2" header, when double that is needed, I'm betting is a huge part of the problem. The velocity is roughly double what the manufacturer recommends, so yeah, you have problems.

If it was me, I wouldn't spend money or time on anything else until that piping is fixed. Attempting to work with what you have is most likely an exercise in futility.

dabrakeman · February 6

If it is "huffing and puffing" then there is water in the main. The main vent should be nearly silent while still evacuating air if there is just air in the main. I have to hold strings or flames up by mine to know they are venting

espire · February 6

dabrakeman said:
If it is "huffing and puffing" then there is water in the main. The main vent should be nearly silent while still evacuating air if there is just air in the main. I have to hold strings or flames up by mine to know they are venting

Interesting... Maybe I'm exaggerating the sound, but maybe not. It's definitely audible from a few feet below. I'll try to take a video of the sound in addition to checking pitch later.

espire · February 6

KC_Jones said:
If the near boiler piping is getting water in the main, the only way it gets back to the boiler is to run all the way to the end of the main, so yes if it's bad enough, it could indeed be wreaking havoc all over the system.

That makes sense! Though if you look at my third photo in comment #16 https://forum.heatinghelp.com/discussion/comment/1789981/#Comment_1789981, there is a jog up 6-12 inches from the near-boiler main before it actually goes to the main that circles the house. What looks like a 90 there is actually a tee, with another 90 out of view. It's hard to imagine any significant amount of water jumping that high unless it's having trouble flowing back into that conveniently located return due to a clog. Though maybe I'm not being sufficiently imaginative

KC_Jones · February 6

For a visual, I'll give you an extreme example to understand, in concept, what's going on.

Imagine you put a garden hose nozzle under that main connection on the header and squirted the water up into the main. Now, where is that water going? Is it going back down, or is it going to flow through the main?

In a steam heating system these discussion are bout steam velocity, if the velocity is too high, it will pull water with it where ever it flows. So while it seems impossible that water can go up that high, in the right (or wrong depending on perspective) situation it absolutely can.

I can make it go all the way up the risers on my boiler if I get my water chemistry wrong, and those pipes go up about 3' from the top of the boiler and my boiler has half the output of yours with twice the pipe volume.

ethicalpaul · February 6

Here's a visual

https://www.youtube.com/watch?v=WSRvvNQ5WLc

delcrossv · February 7

This is a textbook example of when to use a drop header.

espire · February 7

Thanks all for your comments as always.

To make things interesting, I took a level to the main coming out of the left of the boiler. It's pitched up as it goes away from the boiler!

This might explain the banging that happens on that pipe just when the pressuretrol cuts out (combined with the lack of a second riser to the header that @KC_Jones pointed out). After the main reaches the big 4-way intersection shown in an earlier photo, the pitch changes to downward.

I wonder if there is a chance that this makes the single riser issue worse, as the water thrown up by the boiler rolls backwards against the steam. Maybe the counterflow water is more likely to be caught by the steam current and dragged out to the main, even if it requires going a foot vertical.

ethicalpaul · February 7

My main has a short section starting at the boiler that is basically counterflow but it has no effect. What I have observed (thanks to my sight glass that I have installed on my steam supply to my main) is that because this counterflow section is short, the amount of condensate formed there is very small, and it either evaporates as it forms and/or is so very small in quantity that it is never visibly seen as flowing water coming back to the boiler.

There shouldn't be any water thrown up by the boiler at all, if there is, fix that issue.

Having said that, I don't have any good ideas for why you hear a bang when the burner shuts down. Maybe yours is more extreme than mine and some amount of water is being pushed to collect at some point by the flow of steam, then when the steam flow stops, that water is released to flow back...but why that would cause a bang I am unclear. The water should be nearly steam temperature.

One thing to be aware of is that it can be difficult to localize where a bang is occurring. It might not be where you think it is.

espire · February 11

So, thanks to all your help, and especially @KC_Jones for catching all the near-boiler piping issues, I think I have an idea of what might be a way to improve the piping around my boiler. This is certainly not work that I'm comfortable doing myself, but it's good to know what I could ask a competent local contractor to do.

A second riser would be added (yellow), and both it and the original riser (red) turned into "drop header" style to reduce water surging despite the very low ceiling. Both 2" as that's the tapping available I believe.
The ends of the drop risers would be connected by a new horizontal 3" pipe, replacing and slightly longer than the existing pipe angled back into the riser.
In the middle of this pipe would be a tee. Joining into the tee would be a new 3" header with two tees for the mains. It looks like the current mains unions are 3"-2" reducing, so we could now replace them with regular 3" unions.
The header would join the equalizer with a 3"-2" ~~bushing~~elbow.

I think this would improve the situation without having to touch the mains themselves, or the equalizer.
Alternatively, if I wanted to make the job a lot quicker, would I possibly gain a significant reduction in surging just by making a drop header out of my existing single riser? It's not to Burnham spec, but considering that Burnham didn't recommend a drop header, maybe a drop header would provide a similar improvement in steam dryness, without having to modify most of the existing header?
Finally, I wonder, instead of touching piping, would be possible to "downgrade" this boiler to an IN6 or IN5 by decommissioning one or two of the burners. I believe our boiler is oversized, only running for a couple of minutes at a time even on very cold days. I've seen mentions of the idea on other threads but I don't know if it's universally possible or recommended. Probably not an ideal option but maybe a cost-effective one, if it is effective at all.

Would much appreciate your thoughts, thanks!

delcrossv · February 11

The header should connected to the equalizer with a reducing ell. You really don't want to trap any water in the header.

delcrossv · February 11

Like this? Everything should pitch a little toward the equalizer.

BobC · February 11

That would work fine, just make sure the reducing ell is pointing down, if it's in the horizontal plane it will trap water in the header.

Bob

espire · February 11

delcrossv said:
Like this? Everything should pitch a little toward the equalizer.

That's what I was thinking, except in your drawing it looks like the header is behind the two risers. Since my existing header is between the two risers, it would run between the risers and then split into two to join each riser's loop. So the header would be in a T shape. Thanks for the nice drawing!

Pitching towards the equalizer might be tough without starting to play with the mains pipes themselves, though maybe there's a bit of wiggle room to try that. Even totally level would presumably be better than the existing header that has a section running back to the riser.

BobC said:
That would work fine, just make sure the reducing ell is pointing down, if it's in the horizontal plane it will trap water in the header.

Great point. In my case the line to the equalizer is about a 45 angle which is not ideal. I guess it depends on the geometry of the reducing ell whether that is sufficiently pointed down to avoid trapping water.

delcrossv · February 11

That should work. Your tee arrangement should be 3 inch. Usually a 45 down into the equalizer isn't a problem.
Just take the boiler risers as high as possible and drop low for the header.

Bad near-boiler piping (Previously: Was this once a main vent?)

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