Trouble with Slow Radiators and Dry Returns on One Pipe System

merikus

TL;DR: On my one pipe steam system with dry returns, one of my steam runs is 2 to 3 times the length of the others and is slow to heat. It has the same vent as all the (much shorter) others--a Vent Rite #31, vented at the end of the dry return. When I tried open pipe venting as a test (suggested to me by a steam guru--I removed the vent and turned the boiler on), water spewed out of my dry return like Old Faithful. My local steam guy doesn't seem to appreciate the issues I'm having, and I don't know where to turn.

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My steam system has 3 runs (north, west, and south). It utilizes dry returns. Each return has its own drip connection that heads down to the wet return/Hartford Loop. Each of these drip connection has its own vent, and they are all the same: a Vent Rite #31.

The main problem is with the south main. This main services 4 radiators. This is the longest run of the system, at least double or triple the length of the other 2 runs. The thing is these 4 radiators--particularly the two at the very end of the run--just don't get hot. I hear them slowly venting through their radiator vents, but by the time all the other radiators are cranking away in the house and the thermostat turns off, these are barely warm. I checked all the simple things--the radiator vents are not clogged and the valves are fully open.

My first theory is that since this run is so long, and since it is using the same exact vent as the other two runs (which are approximately the same size as each other), the problem is that this thing just needs a faster vent than the other two. So I remembered what a steam guru told me (who I won't identify here but this guy is a true expert and I spoke to him via phone and email)--nothing vents faster than an open pipe--and took off the vent for that run and turned on the boiler to see what happened. I was told that would give me a good idea if I could properly vent that run using just one vent in the same spot as the current one, or if I might have to look at other options (e.g., having a whole new T put in somewhere for a much larger main vent).

I sat there and watched it, and after about five minutes of the boiler running and air coming out of that open pipe, water started spewing out of the open pipe like it was Old Faithful! I quickly hit the emergency off (I was standing next to it) and grabbed a bucket. It kept spewing water for a while before subsiding. I took a quick peek at my boiler sight glass and it was sitting right where it was supposed to be, directly at the recommended level line printed on the boiler.

I took a look at The Lost Art of Steam Heating Revisited, and on Page 102-104, it talks about the near boiler piping and the Hartford Loop. So I took a look at my near boiler piping (diagram and picture below), and I noticed that while I have a Hartford Loop, I don't have a bleeder/equalizer. In theory, that means I should have a check valve on there somewhere--and either that check valve does not exist or is stuck. I have no idea what a check valve looks like, but frankly there's nothing that looks like a valve to me--it all looks like straight pipe.

Picture of near boiler piping/Hartford Loop:



Diagram:



This then lead to Theory #2. About an hour after I ran this test, I went and felt the three drip connections to see if they were still hot (basically to gauge whether there was still water in them). I also want to note that I can't help but wonder if this problem only impacts this one dry return/drip connection system. The one drip connection pipe that I had this problem with remains hot below the boiler water line but not above that line, and the other two drip connection pipes are cool to the touch both above and below the boiler water line. Could my check valves be at the bottom of my drip connections, and that one has failed?

Picture of drip connections:



Close up of bottom of drip connections:



Another close up of the bottom of the drip connection:



If Theory #2 is right, I have another issue that may be related. The PSI gauge on my boiler gets very very high--typically around 25 PSI. I watched it carefully this morning, and about 10 minutes after my boiler fired, the PSI started climbing rapidly until it topped out around 25.

I know this could be a dangerous situation, but I don't think it is actually getting that high of a pressure for 3 reasons:

1. If I was actually at 25 PSI, my radiators would be whistling like crazy. They are operating 100% normally, with just a little wisp of pressure coming out of the vents.
2. If I was actually getting up to 25 PSI, that means both my check valve and pressuresol would have failed, and that doesn't sound likely.
3. I called my local plumber who has serviced this system for years, and he said it's fine, "just a broken PSI gauge, we'll replace it when we next come out."

That said, since I indeed lack a bleeder/equalizer, and since I either have a failed or non-existent check valve, doesn't that mean the system is working against itself? Steam is pushing up the mains and it is also pushing up the dry return, and they are squeezing the air between them, perhaps causing the PSI gauge to register high?

That said, I'm not really sure what to do next. I looked at the local contractor tool here on this site and there's no one anywhere near me. I had my local plumber come by (this was before I ran this test and started having these issues), and while it sounds like he has the expertise based on his background (he has training in steam systems and even has taken a workshop put on by Dan Holohan), he said a few things that gave me pause:

1. He told me my pressuretrol settings should be .5 PSI with a DIFF of 3, when literally everything I have read has said to keep the DIFF at 1.
2. He didn't seem to think insulating the pipes was a good idea, when pretty much everything I've read has said that insulating is a critical part of a well maintained boiler system.
3. I talked to him about my concerns about the main vents being undersized and not allowing the radiators to heat properly, and he didn't seem to appreciate the concern I have, and said the radiator vents would take care of it (clearly they're not).

I'm sort of lost as to what I should do next. This is old, old pipe, and I certainly do not have the skills to install a bleeder (since it would likely involve having to crack open the old rusted together pipe). At the same time I'm feeling like my local plumbing guy doesn't have an appreciation for the problems I'm seeing with the system, and I have no idea how to find someone who is willing to take the time to understand the challenges I'm facing and propose solutions to fix them.

Any suggestions would be greatly appreciated!

ethicalpaul

There's a lot to unpack here.

I agree with your steam guru about taking the vent off to see how fast the steam would get to the end of your long main.

But water spewing out of that hole should not happen. I'm very interested to understand what water spewed out. Did you see, was it clear, or was it muddy? Looking at your vents, it might have been condensation (clear), or it might have been boiler water carried over into the main (muddy).

There might be boiler water getting carried over into your main which would kill all the steam there.

Do those radiators EVER get hot? Like during a recovery from a setback?

Can we see a picture of your steam supply lines into the header, the header, and the risers from the header to the mains?

The drips (or verticals under your main vents rather) might not get very hot. They are full of air and condensate. Steam really won't get past the vents because the air in the vertical pipe has nowhere to go and will keep the steam out.

I don't trust your plumber.

PS: just one more observation: your hartford loop is weird. It shouldn't have that long horizontal on it.

merikus

Thank you for your quick response, Paul. I'll try to take this one by one:

"But water spewing out of that hole should not happen. I'm very interested to understand what water spewed out. Did you see, was it clear, or was it muddy? Looking at your vents, it might have been condensation (clear), or it might have been boiler water carried over into the main (muddy)."

It was very clearly muddy boiler water. Also, it came out with quite a bit of force, spewing everywhere, so it clearly was boiling up from the bottom. It continued to spew for about a minute after I hit the emergency cutoff before it subsided.

"There might be boiler water getting carried over into your main which would kill all the steam there."

I think so too. My theory is that there is water (and thus pressure) going up the dry returns and down the mains at the same time, killing any chance of getting heat to those radiators.

"Do those radiators EVER get hot? Like during a recovery from a setback?"

They do get hot, but it takes a long time. By the time the thermostat turns the system off, only the first section of the radiator is hot--and that's with the adjustable vents fully open. They do not appear to get hot during a setback.

"Can we see a picture of your steam supply lines into the header, the header, and the risers from the header to the mains?"

I've done my best to take a picture of all the near boiler piping:







"The drips (or verticals under your main vents rather) might not get very hot. They are full of air and condensate. Steam really won't get past the vents because the air in the vertical pipe has nowhere to go and will keep the steam out."

That makes sense. Right now, the drips that I didn't run this experiment on are cold to the touch, and the one I did run the experiment on is the same temperature as the pipes below the waterline of my boiler.

"I don't trust your plumber."

I'm at a loss of what to do. I know enough to be dangerous (read We Got Steam Heat, and that's it). Really need a professional to do the work and it seems there's few guys who understand this stuff. Just called my oil provider to see if they have anyone with steam expertise on staff, we shall see.

"PS: just one more observation: your hartford loop is weird. It shouldn't have that long horizontal on it."

Good catch. When I read your PS here I took a look at p. 102 of The Lost Art of Steam Heating Revisited and it's pretty clear that horizontal should be 2".

ethicalpaul

OK your additional photos and description of the muddy boiler water spewing from the main vent port were very valuable.

It is clear to me (and we'll see if anyone else agrees) that your near boiler piping is very poor and is resulting in boiler water being carried over into your main (which you already knew based on brown water spewing out of it).

But many times people will kind of deny that is happening, so I wanted to restate it.

the header is very very low. That is possibly part of the problem.

But that problem is being amplified because the header is crashing into the bull head of the tee at the end of it. So any water being carried in the low low header is splashing up and down. The up splashing water is being carried by the steam up to the main.

the header have taps in this order:
1. the first steam supply (elbow)
2. the second steam supply (tee)
3. some distance
4. the riser to the main (tee)
5. the riser to the 2nd main (tee)
6. the riser to the third main (tee)
7. some distance
8. an elbow down to the equalizer

So this way if there is any water in the header, it gets carried past all the steam risers to the main, and drops back into the boiler.

I don't know if the near boiler piping is the correct size pipe, but for sure the layout is wrong and that is one of the big issues right now.

Where are you located?

ethicalpaul

There may be some things we can suggest to make the system a little better even with the low header and bad piping. That would be:

1. make sure the water is CLEAN (drained and skimmed)
2. make sure the water level is not high (and it might have to be low) to keep it out of the header
3. make sure the boiler isn't overfired (we don't want it making a more violent boil than it has to)
4. make sure the pressure is low (definitely less than 25 psi )

dopey27177

The Hartford loop has a very long piece of pipe in it. the maximum length of pipe to be installed is a shoulder nipple.

Here is a very strong possibility. The base of the wet return can be full of mud or rust impeding the rapid return of condensate to the boiler. When changing the long pipe on the Hartford loop you will need to replace the lower end of the wet return, while doing that you should drain and flush the boiler several times till the water is clear. After that is done some type of chemical water treatment should be installed.

Some times to much chemical is installed based on the instructions so use half of the instructions say. If the boiler water surges drain away small amounts of water til the water level stops bouncing.

The near boiler piping don't look correct. At the least the boiler header must be 24" above the water line and the vent valves need to be 18" above the water line for boilers under 1000,000 BTUs. and 28" above the water line for boiler over 100,000 btus.

Jake

merikus

Thank you so much for your comment, Paul. It means a lot to me. I am no expert in these things, but I did read Dan's book very carefully and noticed some of these problems. For example, you said, "So any water being carried in the low low header is splashing up and down. The up splashing water is being carried by the steam up to the main." When I first fired this system up, I noticed the water in the sight gauge was going crazy up and down. This actually ended up flooding the boiler on two occasions (I think that the crazy up and down kept on feeding in a little water from the low water cutoff, and then when the condensate made its way back to the boiler it flooded it out). When I mentioned this to my plumber he said that was normal. I really don't think it was normal, but again this guy is a master plumber and told me he has decades of steam experience. It's very frustrating because I know his company installed the boiler and (I assume) the near boiler piping. Doesn't give me a whole lot of confidence!

I feel that I need a real expert in here who can recognize these things and can give me a level-headed estimate. I am located in Vermont, although very close to the Vermont/New York border and so might be able to pay someone extra to come from the Lake George/Albany/Saratoga area.

Should I try to drain that drip connection? If so, how?

As for your recommendations, I have a few questions:

"1. make sure the water is CLEAN (drained and skimmed)"

Is this something I can do on my own? If so, how?

"2. make sure the water level is not high (and it might have to be low) to keep it out of the header"

Very good call here. I actually am running it slightly lower than indicated on the boiler and noticed that prevented the flooding problem.

"3. make sure the boiler isn't overfired (we don't want it making a more violent boil than it has to)"

How would I adjust that? I have a Carlin ProX Model 70200 Universal Oil Primary Controller if that makes any difference.

"4. make sure the pressure is low (definitely less than 25 psi )"

Honestly that's the thing that terrifies me the most--although, again, I think the chance that it is running at 25 PSI while my radiator vents are just very quietly putting out little wisps of steam is unlikely. Everything else can be fixed in time (the boiler was installed in 1990 so it does work!), but if there's something causing a dangerous high pressure situation that could be a problem--and it takes so long for that PSI gauge to come down! I want to test my emergency valve but I understand testing them can make them leak so I don't know if I should do that (or how).

Thank you again!

merikus

Thank you for your post, Jake. I agree it looks like there needs to be some significant work here. I agree water must be getting into the mains--these vents have what looks like hard water stains on them, and the only way vents get hard water stains on them is if water is coming out of them, which shouldn't be!

If you happen to know anyone good in Vermont/New Hampshire/Albany, New York area, please let me know. I would be more than happy to pay a quality plumber to come a long distance if I knew they were recommended by the folks on this forum. You all understand this stuff so well, and I wish I could find someone with the level of skill demonstrated here in my area!

ethicalpaul

You're very welcome. I'll answer as I can. First let me clarify my statement here:

> So any water being carried in the low low header is splashing up and down

What I meant is that when water is carried horizontally in the header toward that tee, it will be pushed to the end of the tee and some of that water will spash downward, and some of the water will be spashed upward. The water being splashed upward will get "picked up and carried" by the steam that is also heading upward (toward the lower pressures away from the boiler). There is nothing in your header to separate the steam from that water, and that is the whole point of the header, to separate water from steam.

Now to your questions:

1. You can probably drain your boiler, that one is pretty easy. For skimming, do some searching on this site and on the internet in general (including youtube) and you'll find lots of examples of how to do it.
3. You will need a technician who knows about power burners to make sure it is firing at the correct rate and can then do a combustion analysis to make sure the fuel is burning efficiently and safely. Did you say you had tried https://heatinghelp.com/find-a-contractor/ ?
4. Probably the small pipes and pigtail that deliver the pressure to your gauge and your pressuretrol are clogged. You might send a photo of that arrangement. If you are handy at all with pipes it's easy, but you don't want to break something and be unable to repair it (like a corroded nipple or fitting)

ethicalpaul

Have a look at this thread and see if it doesn't seem familiar. In this video my water was dirty and my near-boiler piping wasn't optimal.

https://forum.heatinghelp.com/discussion/168004/sight-glass-on-main-shows-a-surprise

Then here's what it looks like at the riser to the main:
https://forum.heatinghelp.com/discussion/169320/see-wet-steam-in-the-wild

These threads will have lots of comments in them that you'll find pertinent

merikus

Thanks for your quick reply, Paul. That makes a lot of sense with what you said about the water, and thank you for those links. The video you posted really looked familiar to me. Mine isn't that violent, but it does move around quite a bit and I think that is why I keep getting the flooding issue!

I looked at the information regarding skimming, but I can't for the life of me find a skimming valve on my boiler. I know it is supposed to be there, but I don't see anything around the water line that would allow me to do that.

I did indeed use the Find A Contractor link and it said there wasn't anyone near me, even when I set the milage radius as far as it would go.

FYI, I just fired my boiler up (it's cold in Vermont!) and I noticed after about 5 minutes I was getting water spitting out of my main vents. Here's a picture:



The only saving grace I feel now is that I know the system has been running like this for some time, or there wouldn't be all those hard water stains on the vents. So hopefully a few more months won't hurt anything!

mattmia2

That near boiler piping certainly is...something

Jamie Hall

Argh. Well -- on the steam man. The area you are in seems to be kind of short of people who really understand steam. Don't know why, but you're not the first in that area.

Now however, let's go back to the initial set of comments: you have a steam main, the continuation of which (which you are calling a dry return) comes back to the boiler where it is vented. The radiators on that main don't heat. When you take the vent off and just leave the opening open, when the boiler starts to make pressure, water comes out of the opening. The three vents are perhaps a foot and a half -- 18 inches or so -- above the boiler water level. The water which spews out is murky, like boiler water.

How can we get water that high in that one drip, and not the others? It's being backed out of the boiler by the boiler pressure -- and not being counteracted by steam/air pressure in the return. So... first thing I would do here is wander out in the system, and check that "dry return" for any sags or dips, or being sufficiently out of level -- anything that will trap condensate in it. If that "dry return" were not obstructed, you would get air coming out of the open tapping where the vent is, and when steam got to the vent it would close and the radiators would heat. You need a vent on that opening, by the way, to get a little back pressure in that drip, so water does not get backed out of the boiler.

Never count on a check valve to prevent water being backed out of a boiler. Eventually, a check valve will fail to close completely. Gravity works every time...

JUGHNE

If you look at the tag on the pressure relief valve....it is next to the steam riser coming out of the top of the boiler.....the tag should say 15 PSI. As long as it is not stuck shut, you would not have 25 PSI in the boiler.

If you remove the insulation on the dry return drops, (cut the seam on the long axis, you can get tape to seal that back up), then see if there are check valves on the drops. They sort of look like a valve without a handle, about 3" long and most likely brass....no magnet sticking to it.

Pictures of your results please.

nicholas bonham-carter

Check with the wholesale companies in your area and see if they can give you a list of qualified steam experts they sell to.
they may want their recommendations kept private!—NBC

gfrbrookline

I agree with @dopey27177, sounds like a clogged return on that long leg. I just had @New England SteamWorks install a flush port on my dry returns and the condensate returns to the boiler much faster.

I would also consider putting more aggressive vents on the radiators on the runout to vent the air out of that long run of pipe. Gerry Gill has a great formula for determining the correct vent size needed based on radiator size and location. I used it and it worked wonders to balance my building.

merikus

@Jamie Hall , thank you so much for your comment. Your comment—and an additional experiment I ran this afternoon called “turning the heat on because it is cold”—lead me to some further realizations.

I decided to take a step back and recognize that while there are some problems (e.g., my near boiler piping is messed up), the fact is the system does work. It has worked for 30 years. The previous owner of my house was a meticulous man. He maintained this place in a way I can only hope to live up to. He has used the same plumbing company for decades. He was also not a shy man—he was present for part of my home inspection, and he yelled at my home inspector for not doing a good enough job. The plumbing company told me that he had no complaints. He told me he had no complaints. I have no doubt that if he had complaints, the plumbing company would have heard about them. I also believe he would have told me, because he is known for being honest and no-nonsense.

So the problem here is I’ve learned a lot in a short period of time and, like all beginners, I am finding problems where perhaps there are none. Med student syndrome, I think they call it.

Now that said, there is actually a problem—my south main heats slower than my north and west mains. So it is important to explore that. But I should explore it from the perspective of “this works, how can I make it better?” rather than “this is a disaster!!!!!!," as I am wont to do.

As I said, I ran the system this afternoon. When I did so, I sat in the basement and watched those end-of-return vents. They slowly hissed for awhile, and then the end-of-return vent closest to the boiler started foaming with a little bit of water.

This demonstrates a failure in the design of my previous experiment, the failure to remember the maxim that “high pressure moves to low pressure.” When I ran that experiment—taking out that one vent—I created the lowest zone of pressure in the entire system, a big, open, 1/4 inch hole. And I did that maybe a foot from the waterline (because everything under the waterline of the boiler is always under the waterline of the boiler). Considering how my near boiler piping is messed up, of course water came spewing out of that hole. Why wouldn’t it? High pressure is seeking low pressure, and it found it.

That got me thinking about the system some more. Here’s a simplified diagram—remember, there are 3 runs, and I’m just going to draw one of them, and ever run has multiple radiators, but I’m just going to draw one of them:



So the water boils in the boiler. That water turns into steam. The steam wants to find low pressure. But the problem is there is only one main vent per run, and that one main vent is sitting mere feet from the waterline! So that vent quickly shuts (in part because it is starting to clog with water, and also in part because my near boiler piping is messed up, causing it to surge). But high pressure still wants to find low pressure, so it goes the one place it can, the radiator vents. My radiator vents have become my main vents. Since the north run and the west run are almost equal length, they heat up faster. Since the south run is so long, it is taking too long to vent, and so the radiators never get as hot as the other two runs.

This also answers a question I had--why are some of my radiators double vented? Some of them have radiator vents on both the pipe side and far side of the radiator, and all, save one, are on that south run. It's because the previous owner realized the thing needs to vent, and the plumber kept on telling him it didn't (remember what I noted above about my plumber).

Being this is a parallel flow, dry return system) it needs to be “15 inches back from the end of the main, and, ideally, 6 to 10 inches up on a nipple.” (The Lost Art of Steam Heating Revisited, p. 139

Here’s a picture of that spot, and as you can see it is 100% doable.



I have the headroom clearance. I simply face two problems:

1. A lack of knowledge. How do I get a T so I can install the main vents in the middle of a long piece of pipe?
2. A lack of time. It’s heating season here in Vermont already. It might snow next week. I need my hearing system up and running now.

There are two silver linings here—oil is cheap this year, and the system does work, albeit inefficiently. My plan of action should be to learn to do this job and then wait until the heating season is over. Then do it sometime in June (yes, June, stop laughing) when, if I mess it up, I can go crawling to my plumber and have him fix it for me.

In the meantime, I think I have to use my radiators basically as main vents, as @gfrbrookline has suggested. I think this means double venting my radiators using some very fast vents as a bandaid until next summer.

Oh, hopefully I can also find a plumber who knows what they are talking about by then, and maybe get them to do it/help me do it, and also fix that awful near boiler piping.

merikus

@nicholas bonham-carter, I like that idea! I will have to look around for some.

merikus

@JUGHNE, thank you for the post. Here are the pictures you requested:

Tag:



Pipes without insulation:



As I noted in my response to Jamie above, I think I have a good answer to my venting problem--but I still don't have a good answer to my PSI gauge problem. Maybe it really is broken? It makes more sense for that to be broken than for both my pressurestol and my emergency relief valve to be broken (and for the vents to only be wisps of air).

It is on the list of things for my plumber to fix when they are next here, so that is good.

Jamie Hall

Well, several thoughts here. First, I think you are quite wise to plan to use and observe the system over the winter. Vermont winters can bet a bit tough (I lived there for a while -- much further north), and fiddling with a heating system may not be the best strategy in, say, mid-January! Vermont, it is said, has three seasons: winter, mud, and three months of poor sledding...

Second, on main venting. Many systems which are like yours were vented very much like yours. The vents were placed where yours are, at the end of what many call a dry return (it isn't really, but that's a semantic issue) which was really a continuation of the steam main on around and back to the boiler, and the condensate dropped to the boiler and the air went out the vent -- which was close to the boiler and could be monitored. The concept works, of course. It worked much better with coal, where the fire started slowly and likely went all day, but it works. But... is that really the best place for main venting on a parallel flow one pipe system? Um... let's think about what the vent is for: to get the steam to the radiator takeoffs as fast as possible by letting the air in the main between the boiler and the radiator takeoff out. But -- who cares about the air in all the rest of that pipe going back to the boiler? It doesn't need to be vented. So any main vent location at or after the last radiator takeoff will work or should work equally well. In your situation, that means that you don't have to put a new main vent -- if you decide to get them -- right at the boiler. All it has to be is at some convenient location after the last radiator takeoff. This may help. For what it's worth, you don't absolutely have to have a T to mount a vent. A competent plumber should be able to drill and tap the pipe anywhere, to insert a nipple to hold the vent.

I'm still concerned, though, that that one line doesn't vent from that main vent, but the other two do -- and, relatedly, that when you take that vent off you get a fountain. Your excellent and useful sketch, plus some consideration, may provide some information. You do have an equalizer. You do have a Hartford loop. Now, however, let's consider the pressures in the piping when the boiler is starting to boil, but steam has not reached all the radiators. The pressure in the steam main will be the same as the boiler pressure, of course -- but only at the beginning of the main. As you proceed along it, the pressure will drop, because steam is condensing. By the time you get to the last takeoff, the pressure is likely to be very low. Exactly how low will be determined by the balance between the rate at which steam is supplied by the boiler, the rate at which it condenses, and any back pressure from the vent as it releases air. Is it important? Not really: a conservative assumption would be that it is atmospheric. That means that the water in those drips will be standing higher than the boiler water level. Enough higher, in fact, so that the weight of the water balances the pressure difference -- 26 inches, more or less, for each pound of pressure in the boiler.

Your vents are, in my view, a little low, and it is entirely possible that the problem is indeed that they are seeing water -- all three of them -- and closing, which is what they are supposed to do. The other two mains are shorter and... are the double vented radiators on those mains?

(I still want you to check for sags in the return which is slow -- the long one).

So... where do we go from here? For the short term, I don't normally recommend putting faster vents on slow radiators, but you can try putting very fast vents on the slow to non-existent heat radiators If they are double vented, put the fast vent on the end near the inlet. In fact, if they are double vented -- particularly the last one -- you could try putting a main vent on the end near the inlet; I'd suggest trying even a Gorton #2. You'd have to do some interesting things with nipples and reducers, but it could be done. It might whistle. Second, check what the cutoff pressure of your boiler is. With those vents as low as they are, you may be better off running as low a pressure as your pressure control can provide. If it's a pressuretrol, that may not be low enough -- a 0 to 4 psi vapourstat, set at 1 psi cutout, would be ideal, but I hesitate to suggest it as they aren't cheap.

Then evaluate the system operation over the winter. If it cheers you up any, this kind of thing actually doesn't hurt efficiency -- and your oil bill -- all that much, but it does hurt comfort.

gfrbrookline

I agree, your main vents are in the wrong location. Move them up above the drop. Add more robust main vents, I like big mouths and Gorton No. 2's, and vent your radiators according to Gerry Gills chart and formula and you will have a well balanced system.

Adding a flush port to your returns will let them get cleaned out properly each year and you wont have clogged returns. Mine were only 5 years old and the amount of crud that came out after the port was shocking.

rickster359

Did you disconnect those radiators that don’t get hot and see if there is water them?sometimes it’s just a matter of that radiator not pitched properly on one pipe system causing condensate not going back to boiler.If so drain radiators,reconnect and make sure thy are pitched toward steam valves.Also on the diagram you drew ,as mentioned before the
quick vent should be 15”before the elbow on horizontal part of
dry return with vent 6” vertical.
As to the psi gauge remove it and check for clogged port and fittings,if you cleaned out gauge port and gauge needle
stays on 0psi the gauge should be ok just replace and check.If
system is vented properly you don’t need more than 2lbs operating pressure as per Dan Hollahan, but I find 3lbs works
good for me ;1 cut in and 2differential.The near boiler piping
could be better,but for now for the surging problem try adding
surgex to the boiler water after flushing boiler and return a few times.Hope this helps.

ted_p

ethicalpaul said:

There may be some things we can suggest to make the system a little better even with the low header and bad piping. That would be:

1. make sure the water is CLEAN (drained and skimmed)
2. make sure the water level is not high (and it might have to be low) to keep it out of the header
3. make sure the boiler isn't overfired (we don't want it making a more violent boil than it has to) .......

merikus said:

.......
"3. make sure the boiler isn't overfired (we don't want it making a more violent boil than it has to)"

How would I adjust that? I have a Carlin ProX Model 70200 Universal Oil Primary Controller if that makes any difference......

ethicalpaul said:

......
3. You will need a technician who knows about power burners to make sure it is firing at the correct rate and can then do a combustion analysis to make sure the fuel is burning efficiently and safely. ......

@merikus
I like @ethicalpaul's suggestions for mitigation, short of re-piping (in the event that you can't get re-piped in time for this heating season), and suggest that you take his #3 a big step further....

First, count all of your radiators and determine their sizes in EDR (Equivalent Direct Radiation), then calculate your Total Connected Load. You have The Lost Art of Steam Heating Revisited, which contains good instructions for doing all of this.

Next, compare your Total Connected Load to the Net Output of your boiler to see if it's significantly oversized. If so, when (as Paul suggested) you have a tech come with a combustion analyzer, instead of just having him make sure that the boiler isn't being fired beyond it's rated capacity, have him down-fire it to (or as close as he safely can to) your Connected Load. By reducing the output of the boiler, you'll reduce the exit velocity, which will reduce (or if taken far enough, possibly even eliminate) the water being thrown from the too-short risers into the problematic header.

Not that this would be a substitute for re-piping; but if you can't re-pipe now, it might get you through till Spring; and having your boiler down-fired to the Connected Load will still be beneficial even after it's re-piped.

I can't tell from the pics what model Smith you have, but it looks to me like a pretty darned big (what @Jamie Hall might call "whacking great" ) boiler for a residential application.

nicholas bonham-carter

If you move the main vent location upstream to a point closer to the last radiator on the line, then your headroom For installing a vent will be reduced as the pipe is higher, and closer to the ceiling.
If you want to get through the winter using the radiators for main venting, then put the large vents on the last radiator in each line to get the steam front al the way to the end.
I would also get a low pressure (0-3 psi), gauge on the boiler with a tee, next to the pressuretrol. Unregulated steam pressure Can flood the main vents, as water rises 1.75 inches in the wet returns for every ounce of pressure.
Luckily there is a union below each of the present main vents which will make the job of reinstalling them easier. Depending on the length of the total piping from boiler to vent, you will probably need a menorah/antler/manifold on which to put several main vents. While main vents are not cheap, they are an investment, in reducing the firing time to “steam arrival” at the radiators. The quicker the air in the pipes can be allowed to escape as steam rises, the less fuel is burned pushing the air, at elevated pressure, out of constipated little openings.
The new gauge will show you the back pressure of venting during the call for heat, and on many systems here, it is only a few ounces, if it registers at all.
Many times the plumber will say, “I have 30 years of experience, and always done it this way………” the case is he only has one year of experience, thirty times!—NBC

BobC

The main vents you have are woefully small, they probably worked fine for old coal fired boilers that pretty much ran all winter. Modern oil and gas fired boilers turn on and off many times a day so we have to get that air out of the mains FAST. It would be better if the main vents were up above the the steam mains but for now I would replace the three main vents and I would extend the vent pipes to get them up above the steam mains using whatever size nipple works.

About how long is each steam main and how many radiators does each main feed? You stated this problem main is about 3X the length of the other two so it stands to reason it needs more venting. The mains venting sb fast and the radiators dlow, this helps make sure steam reacges the radiators at about the same time.

Your present main vents are probably venting around 0.1CFM and that is really too slow., lets try an experiment and see how we make out. I'm going to suggest Maid O mist vents because they are cheaper than Gorton main vents and work just fine. Put Maid O Mist #1 vents (0.3CFM) on the two mains that seem to be working, they need a 1/2" or 3/4" coupling so you might need to adapt the piping so they will screw on. On that problem main you want perhaps 3X that venting so an antler has to be built so you can put 3ea #1 vents on the pipe that comes from main. You could just use a Gorton #2 (1.1CFM)but they are about $100 each. That antler needs to be sloped so any water can find it's way back to the pipe it feeds from.

If this works you can look at the radiator venting and the other known issues.

Bob

neilc

The boiler starts and runs and the air vents out of the 2 short mains before the boiler starts to build pressure.
The long main does NOT clear all of its air prior to the boiler pressure pushing water back up to those vents, and those rads on that main stay cold.
The boiler would need to stay under a 1/2# or you're shutting off those vents with A(B?) dimension.
Is the pigtail clear ?
Can the Ptrol shut off at 1/2# ?
Time for a vaporstat.

reason for Edit, "NOT"

JUGHNE

I see no check valves in your drips.

What you could have done is to:

Drain the boiler
Drain the "wet return" portion that is below the 3 drops
Close the wet return drain
Open the 3 unions below the vents
Open the upper union (about waist high) in the long horizontal pipe to the equalizer.
Take the entire assembly outside and remove the not so good boiler drain hose bib
Then flush with garden hose down all 3 drops, all openings in both directions. Even a long brush may be needed.
Install a ball valve where the old boiler drain was.

Then open the union by the sight glass
Open the union right at the bottom of the boiler
Take outside and clean as above
Also replace the hose bib with ball valve.

I have a boiler with this set up and the unions make it easy for cleaning the wet return sections.
The area of piping you are cleaning is acting as a "sludge trap" for the entire system. If you keep it clean then the sludge will stay out of the bottom of the boiler.
Just draining the lower portion of the drop manifold piping each year will let you see how much is collected.
You may not have to remove the assembly for cleaning each year.
The new drain ball valves should be 3/4" full port with hose adapter installed with brass cap.

Once all back together you can fill and drain the boiler until the water is nearly clean.
Filling the boiler to the center of the sight glass will "prime" the return drop manifold.

Get a 0-5 PSI gauge to see what the pressure really is. Put the gauge on a CLEAN copper pigtail with the pressure control.
May have to add a tee and fittings.....brass or stainless steel.

If the drip manifold is full of sludge, that may have been the problem of water back up.

If the bottom of the wet return piping is wet/seeping you should replace it.

You could have 1/4" pipe ports drilled and tapped on the top of the steam pipe after the last take off connections.
A 1/4" opening will handle the Gorton G2 main vent. Raise the vent up on nipples to gain height.
Probably more than adequate for your pipe size and length. You could have a spare port on the longest main. Plug it until needed later.

How about pictures of the end of the steam mains where the returns are connected......also the pressure control and gauge.

merikus

@Jamie Hall, very insightful comment, thank you! I had a phone conversation with my new best friend, the unnamed steam guru today, and he said (more or less) exactly the same thing you did. It's good hearing that I'm getting the same advice from two different people. I have another experiment I'm going to run--running a clear hose out the boiler drain to see how high the water gets when the water is on so I can understand exactly how high that water is getting. All that said, it also leads to a question as to why I am getting water surging that high--is the boiler running to hot? If I'm getting the water going way too high I will consider having a tech reduce the oil nozzle.

The main vent issue is a real interesting one with this system. Your advice squared directly with the advice I got on the phone today--put the main vents on the main, not where they currently are so you're venting less air.

Part of the problem I face is that the dry returns are directly under the mains, so I don't have the clearance to run main vents at or after my final radiator on my two short runs (the north and west ones). Pictures here of the end of those two runs in case you have suggestions as to where I could put main vents here:





Fortunately I have a great place to put a main vent on the slow main right after the radiator, and hopefully I can find someone to help me install it when this heating season is over!

It looks like this heating season I'll need to "vent by geography," using faster and slower vents on various radiators. But at least I have an action plan for next summer when I can find someone to help me fix all this!

merikus

@rickster359, thank you for the comment. How would I check the radiators for water?

I also really should get a level out and see if any of my radiators aren't pitched towards the pipe. It's warm today and will be cold tomorrow, so now is the time to do it...

merikus

@ted_p, very good point about calculating my Total Connected Load and having a tech down fire the boiler to the Total Connected Load. I have a tech coming in a week and a half so I will be sure to do that before he comes!

merikus

@ted_p, quick question on connecting the Total Connected Load. As noted in the pictures that I posted in response to @Jamie Hall, I have returns that run directly under my steam mains. I understand that any pipe that is uninsulated (and, unfortunately, there were a few sections of pipe that I wasn't able to insulate for a variety of reasons) must be included in my Total Connected Load, because they are acting as radiators. Should I include uninsulated returns in my TCL?

merikus

@nicholas bonham-carter, I appreciate your comment about the plumber--I actually asked him to please install a low pressure gauge on the boiler and he said, "I will, a 30 PSI one." I said, "No, like a 3 PSI one," and he said, "why would you want that, you'll have a 30 PSI one!" As you said, one year of experience, 30 times...

I think my plan at this point is to radiator vent for this heating season and then next heating season put some Gorton #2s in the right place and not mess with those pitiful so-called main vents anymore.

However, that leads to a question. While I have a great place to put a main vent on the slow main, the dry returns are directly under the mains, so I don't have the clearance to run main vents at or after my final radiator on my two short runs (the north and west ones). Pictures here of the end of those two runs in case you have suggestions as to where I could put those main vents:

merikus

@JUGHNE, I think that is really good advice, but it is advice I want to follow next summer! I need to spend some quality time with that piping in June--clean it out like you said. But I think the chance of me majorly messing something up is pretty high, so it's best if I hold of on that.

While I have a great place to put a main vent on the slow main, the dry returns on the other two runs are directly under the mains, so I don't have the clearance to run main vents at or after my final radiator on my two short runs (the north and west ones). Pictures here of the end of those two runs in case you have suggestions as to where I could put those main vents:





And here's the pressure control system (I really need a Vaporstat):

ted_p

merikus said:

@ted_p, quick question on connecting the Total Connected Load. As noted in the pictures that I posted in response to @Jamie Hall, I have returns that run directly under my steam mains. I understand that any pipe that is uninsulated (and, unfortunately, there were a few sections of pipe that I wasn't able to insulate for a variety of reasons) must be included in my Total Connected Load, because they are acting as radiators. Should I include uninsulated returns in my TCL?

I don't think that returns (wet or dry) count.

If you just multiply the total EDR of all your radiators times the standard piping and pickup factor of 1.333, and use the result as your Total Connected Load, you'll likely be fine. And since you're just down-firing (which is easily reversible), rather than actually sizing a new boiler, there's no reason to err on the side of caution.

BTW, what is the model # of your boiler? I'm curious how big it actually is!

neilc

, , ,
And here's the pressure control system (I really need a Vaporstat): , , ,

have you checked that the pigtail is clear ?
including the boiler port ?

if you go and move your main vents up to those end of main locations, then the Ptrol should work well enough, it might even shut off at a low enough pressure now, (your vents show a little extra height in later pictures)
IF the pigtail isn't clogged, and the Ptrol can sense what the boiler is doing.
Your comment about the pressure gage going to 25 is a concern for the pigtail.

nicholas bonham-carter

Looks like there is plenty of headroom for the vents in their present location, and the unions make it an easier job.
the extra pipe you are venting won’t make such a difference in the long run.
Having the vents in one central location will make it easier to inspect them and time them.
i have an underlining invasion for some reason!—NBC

Jamie Hall

On "dry returns". Well, that depends. But in a one pipe system, nothing beyond the main vent or last takeoff on the associated steam main counts.

In a two pipe system, with genuine dry returns, the dry returns never see steam anyway. Or shouldn't...

JUGHNE

Is my logic correct in that even if the vents are 50' past the last rad takeoff on the return that the steam will get to the last rad just as fast as if the vents were right there?
There will be more time to get to the vents from that point but does it matter?
He appears to have the returns insulated anyway.

I like NBC's theory to have everything in the boiler room to be seen with each visit there.

nicholas bonham-carter

Since I have 6 dry returns with 3 big vents on each, it is much more convenient to have them at least within 20 feet of each other.
that and the fortunate presence of the unions on the drops make that location much more practical.—NBC 

Jamie Hall

Right on, @JUGHNE !

merikus

Thanks, @ted_p! Here's the label of my boiler for the model number and other pertinent information.