Single Pipe Steam Main Air Vents

northeastconfederate

That return piping is new. The old pipe was fastened to the original brick foundation wall and is what prevented it from fully caving in. Consequently, the pipe was so badly bowed, it could not be re-used. I replaced it and hung it from the ceiling rather than fasten it to the wall.

It is above the water line for it's full length, until it drops down low close to the boiler. However, it is only 23" above the water line at that point, not the 28" it should be (according to The Lost Art...). There is a check valve right before it drops. I think I have a picture of that... The check valve is circled in blue.

The total drop from the far end (near all the 4" PVC drains) to the check valve is just about 8" over 45 or so feet. That condensate pipe, while new, follows the same path it did before the foundation issues. It ties in to the original piping at the end of the main; and to the new-ish check valve near the boiler. I assume the check valve was installed when the boiler was replaced, I assume somewhere around 2008 since that's the year on the builder's sticker.

northeastconfederate

That last sentence should have said "boiler's sticker" NOT "builder's sticker." I used my phone for that post, and the Gottverdamnt thing thinks it's smarter than me and changes things without me noticing it! Infuriating... I shut off autocorrect on my last phone; I'd rather send typos than nonsense!!

Anyway, back to the boiler: I should add that I'm baffled by the waterline. The boiler clearly has lowest permissible water line marked on it. The gauge glass low point is ABOVE this point. Not by much, but it is. The gauge glass is stained badly for the bottom two inches, so it's really impossible to tell if there's water in it or not. I have yet to see water in the gauge glass. I have checked top and bottom valves to make sure they're open, and they are.

I replaced a section of the return piping down near the bottom of the boiler at the beginning of the season because it was so badly scaled that I was worried it would fail during heating season. So, I had the lowest condensate piping apart, and found an incredible amount of muck in those pipes and fittings. Obviously, buildup from multiple water/steam cycles and iron, etc, in the water. So, the lower gauge glass valve could be plugged with this sludge, possibly. But in any case, the water level is either set to run very low; or I have no idea where it really is because the gauge glass valve(s) is (are) plugged. There is what I believe is an electronic make-up water controller installed. I'll post a pic with that circled in another post (since the pic is on my phone and i'm currently using my computer, since it doesn't think it's smarter than me). Maybe someone can clue me in on this device. I can get a better picture of it later today, probably.

All that said, the 23" above the water line figure I gave in the above post is based on the lowest permissible water level, since I can't see water in the gauge glass. So, in reality, the low end of that dry return could be closer than that to the "correct" normal operating water level. This is obviously something I need to address as well.

The more of this book I read, I am beginning to think maybe whoever installed and commissioned this boiler may have installed this fancy water level controller and set the water level to run extremely low to try to deal with excessive carryover caused by him using only one steam riser from the boiler and a too-small header.

northeastconfederate

Here's a picture of that controller (circled in blue). Anyone have knowledge of this?

Jamie Hall

That's a pretty much bog standard VXT -- lots of them out there. They are quite reliable, given moderately clean water. They also tell you how much water has been added. Nice of them. They take a signal from the low water cutoff -- and if it's not feeding water to the LWCO level, which should be somewhere in the lower third at least of the gauge glass, something is amiss there.

What concerns me is the water level you say you are running. You should never run a boiler without the water at least showing in the gauge glass. The water should stand between half way and two thirds of the way up the glad when cool. I would address that problem soonest.

acwagner

I agree the low water level is concerning. Running chronically low on water doesn't leave much of a factor of safety for operation.

I doubt someone lowered it--the autofill usually doesn't put enough water in to bring the level up to normal amount. It just puts enough in to avoid re-triggering the low water cut-off. Over time, the water level slowly decreased until the autofill triggered, and it's been bouncing around that level ever since.

The number on the VXT is, in theory, the number of gallons that have been added, however a number of variables can effect that accuracy.

Check out your boiler manual and it will have a normal water level. Usually measured from the floor.

JUGHNE

Have you found a skim port on your boiler?
Looking at your boiler pictures and having worked on this type previously, there is a KO in the blue jacket that may have a plug behind it. It is on the right side, about 10" down nearly centered in the boiler. Lines up with the 2 top steam outlets.
Or you can skim thru the relief valve port, if that plug is rather stuck which is likely.
For the relief valve port some have removed the 90, installed a tee with the valve on top just as it is now, added nipple and cap on the horizontal run.
MBG is that this may never have been skimmed and can contribute to the wet steam factor.

As for the 2" to 1 1/4" transition in the crawl space, IIWM I would saw the 1 1/4" pipe off first and remove it at your union at the new block wall.
Grind the 2" end of the tee down almost to the pipe threads, then pop it open with a chisel. Then you end up with just the end of the pipe.
Get a 2 X 1/4 90 ell, have it pointing down and add another 90 (or point it at a 45 and add 45) to repipe the dry return back to the boiler. I would raise the dry return at the boiler and keep just enough slope to drain.
You could add a tee in a more accessible place near the new wall for your air venting. This would vent the entire steam main....don't worry about the location of the venting.....as long as it is after the last run out and 16" away from a 90. Many air vents are located right above the boiler. You could/should eliminate the check valve also IMO.

I'm old and often considered lazy for wanting to work smarter not harder. If you don't want to do the grinder route, cast iron fittings can be "cracked" by holding a 10 # sledge against one side and wacking the opposite side with a 2 to 5# hammer.
I am all too aware of the shoulder issues....these hammers will put them to the test. That is the reason for the grinder method.

ethicalpaul

And it must be better to have main venting as close as possible to the best spot rather than no venting.

Said another way, if it’s really easy to put it between the last two runouts vs a colossal pain to put it after that last rad, then go ahead and leave that last rad to fend for itself—the radiator’s vent will let it see steam.

JUGHNE

Paul, all true. But the concentric fitting at the end of the steam main will always have a water issue for the vent. Correcting that and moving the vent to an easy place will get the 2 birds. IMO

gfrbrookline

Agreed @JUGHNE. I have my main vents near the ends of my dry returns in the boiler room. It is nice to have them accessible so I can check to ensure they are working properly. It also helped considerably when I was adding vents to max out the main venting and balance them. I have 3 big mouth on two main returns, three G2's on one an one G2 on the last. It can take some time and trial and error but now my mains fill within a minute and the radiators receive steam at the same time. I have Ventrite #1's on all radiators but the small sunrads in the bathrooms which have G4's and the heat is within one degree.

I also highly recommend the Honeywell VisionPro thermostat which offers the option of multiple wireless sensors. They average the temperature to run the Tstat but also allows you to see the actual temperature in each unit.

northeastconfederate

> @acwagner said:
> I agree the low water level is concerning. Running chronically low on water doesn't leave much of a factor of safety for operation.
>
> I doubt someone lowered it--the autofill usually doesn't put enough water in to bring the level up to normal amount. It just puts enough in to avoid re-triggering the low water cut-off. Over time, the water level slowly decreased until the autofill triggered, and it's been bouncing around that level ever since.
>
> The number on the VXT is, in theory, the number of gallons that have been added, however a number of variables can effect that accuracy.
>
> Check out your boiler manual and it will have a normal water level. Usually measured from the floor.

Oh.... The low water level is my fault, then. I drained the boiler when I replaced some of the condensate piping and assumed the auto fill would top it off to normal. I'm going to have to correct that. Thanks for that info!

northeastconfederate

Most of the piping rearrangements are going to have to wait until spring. I am going to try to tackle the steam risers and header, though that may wind up waiting until spring also. I can't get into something that I can't get out of in a single day at this time of year. If something gets screwed up, I could have tenants without heat.

Now that I know about the main vents' requirement to be minimum 15" from an elbow, I'm concerned about one of the mains and how to vent it. See attached pic. I guess I could re-do the little bit of pipe between the elbow and the end of the 2" main - and now that I'm looking at it, I see it has the same issue as the other main with the concentric bushing. Dammit. But I am planning to pull the plug and install a big mouth vent there. I hope it will provide some benefit and not get damaged. That location is (obviously) in a very low crawlspace. The dry return pipe (I think - I can't get back there right now because of my shoulder's condition) is above ground, but as soon as it comes into the basement, it drops to nearly floor level and becomes a wet return. So I can't very well put the vent in a convenient location.

gfrbrookline

You have so many issues and keep discovering new ones, I would strongly recommend having one of the very knowledgeable steam men in your area evaluate your system before you do anything. They can either fix it or give you a blue print to work from. It will be worth the cost of a consult at least to do it correctly the first time.

BobC

I would also replace the gauge glass so you know exactly where the water is. I also agree this system should be inspected by someone who knows steam, they will spot things you won't see.

Bob

coelcanth

repiping in the crawlspace does not look like a fun job !
if it were my system, at this point, i would take the $80 risk and just install the vent where that plug is now and see what happens. sure you might have to replace the vent again or repipe a bit sometime in the future, but it will certainly work for the time being. it might also work just fine for a long while.

and i don't know why that eccentric reducer is so expensive, but maybe instead you can use a reducing elbow at the end of the main ?

https://www.supplyhouse.com/Bluefin-BLE200-125-2-x-1-1-4-Black-90-Reducing-Elbow

JUGHNE

As mentioned about 10 posts up, might be less work in the crawl space. IMO

northeastconfederate

I stopped in the basement today and checked out the water level. The boiler had just fired and was running, and I found the water level in the middle of the sight glass. The glass is quite dirty, like I said in an earlier post, the bottom 2" are pretty much opaque. So, I guess I must have missed the water line the other day when I was looking. I had to look really close today with a flashlight shining right on the glass, and I still wasn't sure if what I was seeing was a water column in there. I trickled a little water in while watching, and sure enough, it was a water line, because it started to rise. I didn't measure from the floor up. The manual says normal water level is 28.5" up from the floor. I'll check next time I'm there, but it's right around there now.

I'm going to go ahead and install the vent where the p lug is now. Come spring time, when heating season is over, I'll see about fixing up the transition from 2" steam to 1-1/4" dry return, and add some distance between the vent and the elbow. But for now, I'm going to get the 2nd vent installed; leave the one I have in there where it is (on the other main, before the last radiator runout), and leave the hoffman #75 where it is in that run, just after the last runout. I'll worry about that transition from 2" to 1-1/4" on that main in the spring as well.

I am going to do some measuring, make a sketch, get a list of fittings together, and buy the fittings and pipe to fix the near boiler piping. Hopefully, I'll be able to get that done pretty soon. Though, given the condition of my shoulder, that's going to be a little while also.

As far as getting someone to come look, at this point, I have downloaded the installation manual and read some of it. I have the Lost Art book. And some great input from this forum. I'm a licensed high pressure boiler operator with 7 years experience working in power plants, so in general I understand steam pretty thoroughly. I'm now learning about these low pressure boilers via the means noted above. I'm also a former Mercedes-Benz Master Technician. So I'm mechanical. Not to say there wouldn't be any value in having someone who knows these systems com look and consult, but multiple issues have been discovered already. Two have been corrected, at least to some degree, those being the pressuretrol settings and the main venting. The system works, albeit not optimally because of the numerous issues discussed here. I'm going to see about tackling the near boiler piping, maybe hiring my plumber friend to help with that. Those things ought to make a very large difference in the way this thing operates. I'll keep reading and learning, and come spring time address the issues I already know about and any others I discover between now and then.

northeastconfederate

> @gfrbrookline said:
> Agreed @JUGHNE. I have my main vents near the ends of my dry returns in the boiler room. It is nice to have them accessible so I can check to ensure they are working properly. It also helped considerably when I was adding vents to max out the main venting and balance them. I have 3 big mouth on two main returns, three G2's on one an one G2 on the last. It can take some time and trial and error but now my mains fill within a minute and the radiators receive steam at the same time. I have Ventrite #1's on all radiators but the small sunrads in the bathrooms which have G4's and the heat is within one degree.
>
> I also highly recommend the Honeywell VisionPro thermostat which offers the option of multiple wireless sensors. They average the temperature to run the Tstat but also allows you to see the actual temperature in each unit."

I'll save the VisionPro Tstat discussion for another thread. I've been pretty much sold on an outdoor temp reset control with multiple indoor temp sensors, but am certainly open to other suggestions. I'll make a separate thread for that once I've dealt with some of the issues I've found.

dopey27177

Before undertaking replacing piping Insulate the entire steam main except where the corrective piping is to be done.

Lower the cutoff steam pressure to 3psi.

The uninsulated steam main generates a great deal of condensate that will damage your main vents and cause problems with the radiator vent valves.

Jake

I am sending you Chapter five from book on venting. The book is Steam the Perfect Fluid for Heating and some of the Problems.

Available at Dan's library, Barnes and Noble and Amazon

ethicalpaul

Here is a link to Jake's book mentioned above. The price is lower when you actually get to Amazon to buy it: https://heatinghelp.com/store/detail/steam-the-perfect-fluid-for-heating-and-some-of-the-problems

northeastconfederate

Insulating the mains is one of the things on my to do list, for sure.

Shalom

If you have difficulty seeing where the water line is, hold a paper with lines (like an index card) diagonally behind the sight glass, the lines will flip direction at the waterline.

northeastconfederate

We've had some very cold days recently, here. Upper teens for lows; upper 20's and low 30's for highs. A couple of pretty windy days. No doubt the boiler has been cycling often.

The new, big-mouth vent is blowing steam out of it, apparently a lot of it. I got an early morning call from the tenant whose bathroom is directly above that vent because he heard air/steam, and saw steam coming up through the floor!! Obviously, this needs attention.

Here's what I think is happening: For whatever reasons (I'll get into my several theories about that in a minute), there's enough condensate getting into the vent that it never gets hot enough to close, or close fully. These things are thermostatic, right? So if there's condensate in there, it's going to suck the heat out of the steam and prevent the element in the vent from getting hot enough to cause it to close. Do I have this right?

Ideas on why this is happening (assuming I'm right about what's going on with the vent):

1: The vent isn't high enough above the main. Someone posted a diagram showing the minimum distance between the vent and an elbow, which also showed a minimum height above the main. I know I don't have that height.

2. The concentric reducer bushing at the end of the main is causing enough condensate to pool at the end of the main (which is maybe 18" downstream of this vent) that the water backs up into the vent. This seems pretty likely except for one thing: The other vent (the Hoffman #75), which is much close to this bushing, doesn't spit steam or water. You'd think - or I do, anyway - that it would be worse. Keep in mind that the lat runout is between these two vents.

3. The near boiler piping - which we've already established is totally wrong - is causing carryover, so the steam is wet to begin with, resulting in excessive condensation at the end of the line.

4. A combination of all of these factors.


I picked up a couple of fittings yesterday so I can get the vent installed on the "other" main, which currently doesn't have one. That includes a nipple to give the vent some height, more like it's supposed to have. I'll do the same to the vent that's spewing steam. Going to do this later today. We'll see if that has any effect. i'm concerned that the vent that will be installed where there currently is none is going to have the same issues the other one is having, since all the other problems still exist.

Thoughts?

I'm getting closer to asking someone who knows what they're looking at to help. My problem with that is, i've had this system looked at by people who are supposed to know, and professed to know, what they're looking at, and it has become apparent since I've been digging into the system and learning about it that neither of those two people had any clue what they were talking about, despite their fervent belief that they were expert. I am very reluctant to pour more good money after bad for more bad advice. I don't need this system F-ed up worse than it is, or to spend money for misinformation. I'm more inclined to become educated myself and get it sorted out. I just don't know if I have time or leeway for that to happen. Pretty frustrated!

acwagner

My vote is standing water in the main because of the concentric reducer. Big Mouths are not very tolerant of adverse steam system conditions based on other discussions on this site.

Gsmith

Wouldn’t hurt to have someone qualified look at it. Have you tried find-a-contractor on this website? Where are you located?

Hap_Hazzard

acwagner said:

My vote is standing water in the main because of the concentric reducer. Big Mouths are not very tolerant of adverse steam system conditions based on other discussions on this site.

I agree. The Big Mouth vents fast enough to create a lot of turbulence and pick up water.

northeastconfederate

> @Gary Smith said:
> Wouldn’t hurt to have someone qualified look at it. Have you tried find-a-contractor on this website? Where are you located?"

I'm in Central NJ. The property is specifically in Bordentown Township.

I have not tried to find a contractor on this site, though a couple were recommended to me early in this thread. Though while they are in NJ, I don't think they are nearby. More like closer to NYC, which doesn't help.

northeastconfederate

Hap_Hazzard said:

acwagner said:

My vote is standing water in the main because of the concentric reducer. Big Mouths are not very tolerant of adverse steam system conditions based on other discussions on this site.

I agree. The Big Mouth vents fast enough to create a lot of turbulence and pick up water.

I'm going to elevate the vent and see if that helps immediately. I'll correct the concentric bushing next week wnen the weather warms up a little next, and see what happens with that.

Hap_Hazzard

northeastconfederate said:

I have not tried to find a contractor on this site, though a couple were recommended to me early in this thread. Though while they are in NJ, I don't think they are nearby. More like closer to NYC, which doesn't help.

It doesn't hurt to ask. Some of them might have clients in central NJ that they service on a regular basis, so you'd be making a trip they're already taking a little more worthwhile. Also look for contractors in eastern PA.

northeastconfederate

I went to the property yesterday and witnessed the vent steaming myself. It didn't come out with a lot of force, but it sure did emit a large volume of very wet steam, which absolutely drenched everything in its path.

I elevated the vent so there is now 9" between the top of the main and the bottom of the vent. I also piped the outlet down towards the floor. Hopefully this gets the water off the framing until I can get the rest of the piping sorted out. I stuck around through a couple of boiler cycles. The vent definitely never closes. It stops emitting steam and water when the boiler cycles off. So, I'm convinced there's just too much condensate standing in that pipe. Going to have to address that pronto.

Jamie Hall

Interesting contrast there. That old Hoffman 75 (old design, even if not itself old) closes at relatively low temperatures (I seem to remember 140?) and has a float. Pretty close to bulletproof. The Gorton #2 is also a relatively low temperature design with a float. Bigger than the 75, but only about half as fast (and a lot more expensive!) than a Big Mouth. The Big Mouth is based off a steam trap, and is higher temperature, with no float. There are good applications for each of them...

Sailah

It sounds like the Big Mouth is bad. Call them and get a replacement.

dopey27177

Looking at the check valves scares me. Check valves are only used for special problems that can occur with the original steam piping. These are used where two pipe steam systems are installed and none mechanical boiler feed valves were installed in gravity vacuum systems.

if what you say {the end of the dry return is 23 inches above boiler water line I would remove the check valves because they can get stuck or prevent the condensate from draining fast enough out of the steam main and cause water to be held in the steam main and cause the main vents from operating correctly.

The spitting is caused by retained water in the steam main. s to the lower section of the dry return I would drop that to the floor and leave it as a wet return. Do not forget to to install a Hartford loop. Also when all the lower piping is removed Drain and flush the boiler and clean out the the lower section of the boiler you will find a load of sludge in the bottom of the boiler.

While you are at it replace the gauge glass ( buy a gauge glass cutter and new gauge glass washers. Clean out all the pig tails on the front of the boilers (replace the 1/4" piping where needed and clean out the low water cutoff.

Jake