five cold radiators on three risers, I'm scratching my head

niftyc_2

I have five radiators that have been behaving erratically since I bought the house a few years ago, but now they are all not heating, and it's the first snow of the year. I'm a big fan of Dan's books and this board has helped me out in a number of ways over the years. I wonder if anyone has time to look over my shoulder and check my reasoning on this problem. I would really appreciate it.



I have a K-M-C vacuum system from 1904 -- but it can now be thought of as fancified one-pipe steam with basement (main) venting. I am running very low pressure (cut out at 1 psi) and the cut out is rarely reached that I have noticed.



All of the problem radiators are in the same area of the house. They are 2nd floor and attic radiators served by three different risers. The risers are insulated in the walls.



From the books and my past experience, it seems like the problem is always the venting. "Maybe it's unbalanced," I thought. So to diagnose this I opened all of the problem radiators to atmosphere on the far side. In other words, the vent holes are wide open. Then I cranked the system. It took a while, but the house heated to 80 degrees. Every single radiator (including other 2nd floor and attic radiators) heated all the way across except that the five problem radiators remained stone cold. This leads me to think it is not a venting problem.



After a while (over an hour) one of the problem radiators heated a little bit and the riser at the inlet for that radiator made a continuous watery sound that reminds me of gargling. I have no idea what this means.



During this long test I held a candle near the vent holes to check for movement of air and I did get some. On system start-up I got a bunch of venting from one radiator (loud whooshing!) for a few seconds but then it's like that part of the system somehow plugged itself. Air movement stopped and it didn't do anything again. On a second problem radiator I got a faint movement -- mostly out, but sometimes in like the radiator was breathing. On others, nothing.



In a previous discussion back when I thought my problem was more localized someone suggested a blocked riser. But three risers are involved so I don't think that could be the case. And one of the risers did eventually heat (the gargling one).



So I'm asking myself, what do all of these problem radiators have in common. All of the problem radiators are fed by the three risers connected immediately to the left of the steam main in this picture. And those risers are all in a row. No working radiators are connected between them. So I'm figuring if I stare at this area of the basement long enough I'll understand what is going on.



You can see that the original steam main that circled the basement has been modified -- initially steam supply flowed in at the left and out through the back wall. Then a wanna-be "express" main was added coming in from the right and someone put in this U-thing (which seems foolish to me).



My steam pro says we should drip the U thing as it is surely collecting water and that is the source of my problems. I'm willing to buy that, but I opened the bottom of the "U" pictured and drained about 5 cups of water, then fired the system -- yet this did not affect my radiators that did not heat. I think he is right I should drip it, but I don't think it will fix my problem radiators.



My steam pro also suggested a main venting problem but I think I've ruled that out by opening the problem radiators to atmosphere. They should have all the venting they want at this point, yet it doesn't help.



The steam mains pictured here are very close to the boiler and they heat almost immediately, yet the "problem" risers remain cold. All of the other risers in the house are steam hot yet the three problem risers remain cold. After some time (30 mins?) the problem risers will become hot in the basement but I can't detect that heat anywhere higher up.



At this point I'm just not sure what to think. My best theory is that this is a water pocket caused by bad pitch in the supply main to the left of this picture? If so I'm having a hard time visualizing it in my pipe layout. It would have to affect three risers and not be corrected by me draining this strange "U". So you see I'm scratching my head.



Flaws in my thinking or other ideas?



Thanks so much for your attention.



Christian

BobC

Check all the pitch

I would use a level to check the pitch of the main and make sure I knew how it was pitched and how the steam was supposed to get in AND how any water was supposed to get back to the boiler. Don't trust your eyes.



I suspect some modifications have been done that may not have been good for that system. Also the house may have settled unevenly over the last 100 years screwing up pitch.



Steam will not go where there is trapped water, the gurgling you sometimes hear is proof that there is trapped water somewhere. Are there any other houses in you area about the same age that might give you a clue what was there before that U was added?



Bob

JK_3

The u thing?

If I am reading the post right, you are saying that all of the problems are to the left of the U. What is it there for. You can try removing the plug on that tee and run the system, see if steam ever gets there. also with the plug removed see if the steam goes up. I suspect that with that deep of a water seal steam cant get past but with the plug removed it will eventually go up. Even dripping that tee to a pump or other return most likely would work but the steam would fill most of the rest of the system before going there. I would test this way and then if correct why cant the U be eliminated

JK_3

The u thing?

If I am reading the post right, you are saying that all of the problems are to the left of the U. What is it there for. You can try removing the plug on that tee and run the system, see if steam ever gets there. also with the plug removed see if the steam goes up. I suspect that with that deep of a water seal steam cant get past but with the plug removed it will eventually go up. Even dripping that tee to a pump or other return most likely would work but the steam would fill most of the rest of the system before going there. I would test this way and then if correct why cant the U be eliminated

Abracadabra

Drip that "U"

"After a while (over an hour) one of the problem radiators heated a little bit and the riser at the inlet for that radiator made a continuous watery sound that reminds me of gargling. I have no idea what this means"







Water is collecting somewhere and steam is trying to get past the water, giving you the gurgling sound.



Does the main from the left get vented anywhere?  I'd bet it doesn't since it loks like originally it was meant to continue on to the left.  Does the main from the right get vented anywhere?

 I opened the bottom of the "U" pictured and drained about 5 cups of water 

That "U" you drained filled up with more water from condensing steam from your uninsulated mains within 5-10 minutes after your boiler started steaming on the next cycle. 

Do this as a test.  Follow the steam along the pipe  with your hand.  You will feel the TOP of pipe get hot.  The bottom will get hot with hot condensate. Follow the steam and see where it stops or slows down.  Time how long it takes to get from the header of the boiler to the takeoffs to the risers.

Pics of near boiler piping? A diagram of your main lines? Vent locations?

niftyc_2

looks like a water pocket causing it?

OK here's some more information:



JK: If I open it up at the U and run the system water will not collect, obviously, but that will mean operating the system with an open steam main in the basement. That seems like overly exciting diagnostic test! Is that really wise? I am a little afraid of doing that.



Abracadabra: I have no main vents. The near boiler piping is a giant mess. It is totally wrong. However, my thinking is that since these radiators used to heat, and the near boiler piping looks like it was screwed up a long time ago, I'm thinking that is not the work I should do today. Something else must be the cause. I'm trying to do something good for this system every year until it is pristine again and I think the near boiler piping is not in this year's budget.



New information:



Two pipe hangers in the problem area are broken. Other pipe hangers in the system are intact. Pictures attached. I am assuming this means the main is not at the level the designer intended anymore.



I checked the pitch and it is crazy. The start of the problem main is pitched pretty strongly back to the boiler. This appears to be intentional as the pipe hangers are intact. Is this correct? I thought the boiler was supposed to be the high point.



Then the pitch gradually levels out near the first broken hanger and changes direction. Then it changes direction again at an elbow, meaning I must have a low point and a water pocket there. This pocket would be just before the two risers that never heat, and it would be near-ish the gurgling riser. I'd guess that is my problem?



Next the pipe changes pitch again, creating a second low point in the "U" thing we have been discussing.



I ran the system and watched the water level. It starts out flooded (no water line visible), then drops to halfway in the sight glass for a while, then drops a little lower. I'd guess the condensate can't return to the boiler because of these pitch problems and this is causing the flooding. I'm pretty sure the wet return is not clogged because I replaced it two years ago.



I'm still having a problem visualizing this water pocket because when I try Abracadabra's "follow the steam" method when the system runs the problem mains do get very hot even where this pocket should exist. (Yet the risers do not heat.) However the existence of this low point just before the two non-heating risers seems like the best explanation for my problem, right?

JK_3

it will be ok

What pressure is the system running at?  If the pressure is low and you run with the tee open you will/ should get steam out so you should be very very careful. to be safe about it I would run a pipe from the tee to the floor , u turn back up to a few inches below the tee then uturn again to a bucket. this will allow any condesate to drip from the main without steam leaving ( you need 30" of turned up hight from the floor for each pound of pressure).

Also I would reconnect those hangers to eliminate places where water can collect. Low spots where the top of the low spot is still higher then the bottom of the high spot will restict steam movement but not block it. This causes water hammer but the steam can still pass.

Dave in QCA

You're making progress

I have read through the posts on this thread, but have not read over twice, I may have missed some details.  Apologies if I have.



You have identified your system as a K-M-C system.  This is a vapor system that is somewhat similar to a Paul system where each radiator vent was connected to small piping that went back to the boiler room and was connected to equipment that produced a vacuum on the system. If your radiators are no longer connected with a second pipe to the return system, it is doing much less of its function that originally designed, but it may still be doing something. 



You have identified that the pitch of the pipes is not correct and have shown pictures of 2 hangers that have come loose.  Correcting this issue may fix your problems.



But, what about that shallow "U" ?     This is an example where a dozen pictures would be of great help along with some more descriptions.  But, I'm going to go out on a limb and take a guess that when we're looking at the picture of the "U", that all of the radiators are connect to one pipe, and the other pipe goes back to the boiler.  Is this correct?   If so, that U is a water seal and is there to prevent steam from entering  the return pipe.  If it dropped to the floor and went back to the boiler as a wet return, it would keep the steam out.  This little U, or water seal does the same thing.  Many system just have the steam main go all the way back to the boiler, and that pipe heats up fully to the temperature of the steam, but this is just another way of doing it.   (unless my assumption is all wrong....)

The K-M-C system also usually had a type of crossover trap, from the steam main to the air return piping.  Their drawings show an "air vent pipe" coming off the end of the steam main, connected to a "retainer valve" that then connected to the air line.



Does your system still have anything like that?  If not, since you are not really running any of the KMC equipment... or at least that is my impression from your post, then installation of main vents would be a really good idea.



Also, If my assumption regarding the mains connected to that U is NOT correct, then it should be dripped, but I don't think that's the case.



More pics please!

niftyc_2

don't think I can open it there

I really appreciate this help and your patience.



Uh, oh. I don't think I can get that pipe open there. That plug looks rusted solid. To drain it I opened those bolts on the union (is that the right term?). And running new pipe is also beyond my expertise.



But your reply is bad news for my efforts to find the cause. I don't think it is possible that there could be a complete water seal given how hot the main gets there and the fact that the pipe has only fallen a little. The top of the low spot is still much higher then the bottom of the high spot.



Mechanically how do you raise the pipes to reconnect the hangers? I will ask my pro but do you use a bunch of pipe stands that you jack up slowly or something? These things seem immobile. Clearly I don't know what I am doing though.



Christian

niftyc_2

the "U" is not original

Dave, thanks so much for your thoughts.



The U was not original that I can tell. I think that originally (1904) the steam main ran around the edge of the basement and steam would enter from the left side, then go through the hole in brick wall pictured in one pipe. At some later point (guessing c. 1940s) someone added this express main coming from the boiler that enters from the right, and turns right. They added the U for reasons unknown (to me). They changed the steam distribution pattern from a single gravity return main with condensate flowing in the same direction as the steam, leading to a wet return to a kind of octopus or star shaped thing with several express mains going here and there that are pitched as counterflow. Or maybe "hairball" would be a better metaphor than star or octopus.



Radiators are connected both to the left (but they are the problem ones that do not work) and farther along the main through the hole in the brick wall (and those work fine, presumably served by the express main entering from the right).



I can send more pictures if you tell me what to photograph.



I know I have to think systemically but I am fearful of broadening the discussion to my entire system because there are so many things strange about it -- it is a Frankenstein. I do have the original KMC air return system and I am using traps on each radiator at the air lines. I have added venting to the system and people on the board were very helpful with this. But I don't think venting is the problem here because I disconnected the vents on the problem radiators and opened them to atmosphere in order to rule that out.



I have seen the steam main/air line crossover traps on the original KMC patents but mine have been removed at some point. That means I need to add venting to my mains, since the crossover was performing that function. It is on my list but I am trying to do a little each year. I don't think main venting is the problem here because the radiators used to work.



I am still leaning toward water pocket due to pitch but my last exchange makes me unsure because I don't think the pocket could be that big.



Christian

Dave in QCA

The pictures the better

It would be helpful, if you want good answers, to give us the whole story.  Take pictures of everything, draw diagrams, etc.  When we can't see the whole picture, the best answer that anyone can give is based on only what we can see, or think we can see.  This gives answers that at best, should begin with, "it all depends," and that is not going to help you much.



Regarding the mains in the picture, I'm trying to understand.  Are you saying that the main on the lefts is a steam main, and it is sloping downhill from the boiler, and that essentially that main ends where it drops in the U.  And secondly, that the main on the right is also a steam main, with the steam is coming in from the right, pitched downhill in the direction of steam flow, which is on through the brick wall?



If so, (it all depends) but from what I can see and the information that I have, I would say that it is a drip connection from the low end of the left steam main into the right hand steam main.  Thus, the condensate is allowed to travel in its original path, if your assumption about re-piping is correct, but the steam is stopped by the water seal.   It is unusual, but nothing really wrong with  as long as the piping to the right has the capacity to handle the condensate and the pitch is correct.

JK_3

Just for test

You might need a steam professional to look at and possibly do some tests on your system. Have you tried "find a professional" for your area?  There may be other connections you are missing. Maybe you could try drawing the entire system out for us. You can do it over several drawings with the first being a general one with notes to see detail drawings and pictures.

If I wanted to test this therory quickly I would lossen the bolts on the flange just enough for the water to drip out,once it dripped completly out I would run the system(leaving it to drip out) and see if the risers now get hot. I would not reccomend this to anyone but myself because of the danger involved, steam will be pushing out there with very very hot water and could also spray and could burn someone (don't try this at home LOL).

JK_3

Just for test

You might need a steam professional to look at and possibly do some tests on your system. Have you tried "find a professional" for your area?  There may be other connections you are missing. Maybe you could try drawing the entire system out for us. You can do it over several drawings with the first being a general one with notes to see detail drawings and pictures.

If I wanted to test this therory quickly I would lossen the bolts on the flange just enough for the water to drip out,once it dripped completly out I would run the system(leaving it to drip out) and see if the risers now get hot. I would not reccomend this to anyone but myself because of the danger involved, steam will be pushing out there with very very hot water and could also spray and could burn someone (don't try this at home LOL).

niftyc_2

I have a steam pro, but this is sort of a team effort

After going through several knuckleheads I do have a steam pro I am working with. He has been very encouraging of these do-it-yourself investigations. His point to me is that since I already think about this system all day, I might as well save him time by doing self-diagnosis.



Also I had to go through so many knuckleheads (four) I'm not sure I fully trust pros anymore, so I am all for self-education. This pro seems good though. Christian

niftyc_2

why would someone want a water seal there?

Thanks, Dave. Here are a few somewhat randomly selected pictures: http://www.flickr.com/photos/niftyc/sets/72157608801023873/ I will post more pictures when I am home.



Yes, I think your textual description of the "U" has it right. I have annotated the picture to what I think is going on to be sure that we agree.



I think I understand you -- that the U is functioning as a water seal -- but why would the installer want a water seal right there? I don't see what would be bad about connecting the main on the left (which I think was original) directly to the new main that comes in from the right without a water seal.



Christian

Dave in QCA

Because

You never want to feed a steam main from two directions at the same time.  That is what would be happening to the main on the left if they were connected together in a straight manner without the water seal.  They could have piped a separate return from the main on the left back to the boiler, but someone was using his head and come up with the water seal.  I am sure it does exactly what the installer wanted it to do.  Now, you just need to get those sags lifted up and straightened out.

niftyc_2

Here's a picture

Dave, that's great -- now I understand the U shape. I'm so glad I didn't drip it or have it removed! I owe you a drink (and probably more) for your help the next time you are in champaign-urbana.



I took your advice and I drew a picture of the problematic area for you. If water is sitting along the dead level part of the main along the top of the picture, do you think this would cause these three problematic risers?



Looking at my level and the pipe hangers it is also not clear to me what the designers intended the high point of the system to be. The strong pitch to the boiler is clearly intended, but all the pitches along the top are not clear (to me).



Along the top is also a long run without any pipe hangers so that seems strange since they are regular everywhere else.



Christian

Abracadabra

Fix one thing at a time.

Fix the sags in the main and ensure that the main has proper pitch.

JK_3

now it makes some sense

Yes dave is right. I believe that the first broken hanger should be the high point in the system. If pitch allows, the second broken hanger should hold that main slightly higher then the good main on the other side of the U. At the least you would want the pipes on both sides of the U to be dead level with each other. The condensate from the first part of the bad main (before the hanger) should flow back to the boiler. from that hanger to the U the condensate will flow with the steam up to the U where it will enter the other main to flow back to the boiler.

jpf321

if you want to get steam to the far side of a water trap ...

if you want to get steam to the far side of a water trap ...  have a read of this recent thread ...

http://www.heatinghelp.com/forum-thread/139100/stumped-and-need-your-help



In my case, I wanted the return water to get past the very deep trap .. but it works just the same to get the steam across .. of course, you'll need your pro to replace those elbows at the top of your U with t's.

Mike Kusiak_2

Pitch of runouts?

I am not completely convinced that the main is really the problem. There may be level spots along the main, but would enough water collect there to completely obstruct the flow of steam to the risers? Looks like the main would have to sag several inches for this to happen and from the photos that doesn't seem to be the case



Are there any horizontal runs of pipe to the radiators in the upper floors after the risers from the basement? If due to settling these horizontal pipes lost their pitch, it seems that they would more easily block off steam to the radiators involved than the mains themselves.



Have you tried raising the problem radiators slightly to see if this might change the pitch and allow steam to reach them? The one that gurgles and gets slightly warm might be a good candidate to try first.



If you want to try and raise the sagged sections of the main at the broken hangers, you might try a car jack and an appropriate length of 2x4. Put one end of the 2x4 on top of the jack and the other under the main. Slowly raise the jack until the main is in position and see if it changes anything. I would try raising the hanger location at the elbow first as it looks like it might have the greatest effect.

niftyc_2

not sure about equalizing it

I think Dave's point is that I don't want to get steam across the U, it is an intentional water trap to prevent steam from feeding from multiple pipes. Remember that steam feeds both sides of it already (see annotated photo).

niftyc_2

there's no shared runout

Thanks for thinking it through with me Mike. I am also worried that less than an inch of sagging main cannot explain all this cold iron. But it seems more plausible to me than a problem with a horizontal runout. Since there are three risers involved I don't see how they could share the same horizontal runout problem. (But I'm no expert.)



I think I will try raising that main pipe and re-hanging it and then see if the situation changes.

Dave in QCA

A different set of conditions

JP, you are correct to realize that this looks similar to that tough situation that you were working on, but it's not the same.  In this case, there is already steam to both sides of the U, so pressure is already equalized.  The purpose of the U in this case is to prevent the steam from corrosing from one main to the other, but at the same time, allow the condensate to flow downhill.

Dave in QCA

Proper Slope of Main

This is in response to your question regarding the proper slope of the main and where the high spot should be.  You diagram is very helpful.



In the best case scenarior, the highest point in the piping should be at the point that the main connects to the header above the boiler.  However, in your case it sounds like there is an upward slope away from the boiler for a short distance.  This is not ideal, but also somewhat common in existing systems.  It should not be a big issue as long as the main is sloping the other way by the time the first radiator connects.   So, that is where I would start.  Try to raise the main where it is flat or sagged, and keep working your way back to that high point that isn't so high.  As you raise the main, make sure that you don't raise it so much so that you create a puddle in any lateral or runout to a riser or radiator.



Let us know how you make out.

niftyc_2

UPDATE: fixing main pitch produced no change

OK my goal for the day was to raise the steam main to the place where it seemed like they were supposed to be originally before the pipe hangers broke. Please excuse me if this is a ridiculous method to do this. I don't know what I am doing. I got a bunch of 2x4s and cut them slightly longer than the distance to the floor and went around the basement kicking each of them with a sturdy boot once in turn to raise the pipes evenly. (Pictured.) I raised the low point a little over an inch. Then I used galvanized strapping to hold the pipes up so that I can change things without too much trouble if you guys tell me I did something wrong. Doing this pipe-raising caused one radiator on the second floor to "hang" off the riser and its legs to be slightly off the floor, so I shimmed it.



So, success at what I attempted: there are no longer any flat spots in the mains. I opened the other end of the 5 problem radiators to atmosphere to be sure there was no venting problem. Then I fired up the system and... (drumroll) NO CHANGE. It looks like Mike was right. The five problem radiators are still cold. If anything, the one gurgling radiator that used to heat a little tiny bit occasionally now did not heat at all.



On the other hand, the risers coming from the steam main now heat in the basement. They did not do this before. But I can't detect the heat anywhere above the basement. I got the house up to 78 degrees with all other attic and second floor radiators heating all the way across before giving up. Sigh.



I checked the air flow at the radiator vents with a candle (pictured) and I got a some regular faint puffs, but really very little air at all. At least it was not sucking in.



I have re-drawn my diagram (attached) to show the new state of things.



I know Dave wanted me to slope the main the other way before the first radiator but I was not sure how to achieve this. A lot of pipes are there and there are intact pipe hangers in the area. These pipes don't seem to have fallen, so I did not feel confident enough to change them. I followed JK's note and made the indicated elbow the high point because that appears to be the intended high point.



I am a homeowner who is terrible at any kind of DIY thing. With that in mind, I'd say doing this was not as hard as I expected. There seemed to be a surprising amount of movement possible with the piping if I just kicked one 2x4 at a time and went up and down the lengths of the main raising it slowly.



I'm not sure what to think at this point. This section of main (as you see in the picture) has no insulation on it. All of the rest of my pipe is insulated. The risers are insulated. Could a lack of insulation be creating this problem?



My mains have no vents. If I understand Dave the left side of my U-shaped water trap is effectively the end of a main. Maybe that should be vented? Or maybe the U-shaped water trap is not functioning correctly? It is certainly suspiciously placed in relation to my problem (see diagram).



Ugh. I am just guessing here. And I don't know what I'm talking about!



I really appreciate your time helping me with this puzzle. Any ideas about another diagnostic step?

Mike Kusiak_2

Latest results

Sorry to hear that raising the main had no effect, but one thing may indicate some progress. You mentioned that one radiator which gurgled and heated somewhat now does not heat at all. Could raising the main at that point also have raised the riser and a lateral run of pipe above, trapping more water with increased reverse pitch?



 Just seems interesting that raising the main and riser made a problem worse rather than better, but it might confirm the "runout theory". Can you try to raise the formerly gurgling rad somewhat an see if it again gets some steam?



You also mentioned that raising the main also raised one radiator off the floor. It would seem that there would have to be a direct connection to that riser with no horizontal lateral involved. Does that radiator heat?



My final comment seems obvious, but have you confirmed that the valves of the affected radiators are actually fully open? Is it possible that the valves seem to be open, but are broken partially or completely shut, trapping water in the rad and preventing steam from entering?

niftyc_2

can it puff air with a shut valve? or a blockage?

Well it did improve the problem sort of -- the bottom of the risers in the basement now heat. Before that steam stayed in the main only and the risers were totally cold.



No, the radiator that moved did not heat. I do think it is very close to the riser given the position relative to the riser in the basement.



It would be just like me to have caused this whole thing by closing the valves, but I don't think that is the problem. All inlet valves have movement. Using righty-tighty, lefty-loosey I have long ago insured that I opened them all the way. I just double-checked them. The same valve position on other attic radiators produces a working radiator. Also I don't think I would have gotten even the meager puffs of air that I did get if the valve was shut tight. Here is a slightly better picture of a puff.



I can try raising the formerly gurgling one and see if that does anything. I need to wait for my friend to come over with his big crowbar though, so it won't happen tonight. It seems like what I want to do is work out where the laterals are in the floor and walls so I know which one to raise. Is there any good way to do that beyond guessing?

Dave in QCA

darnit!

Sorry that you have not resolved the problem.  I am going to assume that you have put a level to the laterals and runout and have determined that there is no slopes in those areas that could create a puddle.



There are two things I would like to have you try. 

       First, pick 3 of the radiators that heat very well, preferably on the same main, and turn the supply valves off tightly.  See if this causes any impact.  Your boiler may be underfied or too small to be able to heat all of the radiators.  This would be a good test.

       Second, while the boiler is running, clock your gas meter and see how many cf you use in a minute.  Multipy by 60 then by 1000, this should be very close to the input rating on the boiler.  

Do both of these things and then report back.

Mike Kusiak_2

Broken valve?

Have you ever tried opening one of the valves on a bad radiator and try to see inside?  What I was referring to was a valve that appears to be open, but has a broken sealing disc which is partially blocking the valve from passing steam or returning condensate.



If the vertical riser is hot with steam at the bottom and connects directly to to the radiator at the top, then I can't think of any way that steam would not enter the rad unless the valve was somehow blocking it directly, or holding back condensate indirectly blocking the steam. The fact that the air vent hole is completely open eliminates the possibility of trapped air.



So what else can be blocking the steam?

crash2009

Vacuum?

This might sound a little silly and it probably wont fix anything.  But, have you ever tried vacuuming those cold radiators?  A few years ago someone suggested that to me, and I thought they were nuts, but I was desperate enough to try it.  What I did was remove the vent and hold the shopvac hose up to the hole.  Eventually the vacuum pulled the steam into the radiator.  The sections got hot one by one, including the last one.  Then the shopvac let out a little squeal and thats when I knew I had vacuumed too much.  I don't know why, but once I get the cold one hot, it stays hot for the rest of the winter.  I have used this little trick several times with success everytime.  I suggested this to a guy from Calgary.  He built an attachment for his shopvac hose that he stuck right inside the radiator.  He reported that it worked, and that was the last time we heard from him.  That was 2 years ago.  Hope it works for you.

niftyc_2

Four gallons of water came out!

So in my "try anything" mentality (the vacuum will be next, thanks for that crash) I fired the boiler with the union at the bottom of the "U" water seal OPEN as JK suggested. (see annotated photo of "U" above). When I opened the union with the system cold I got about 4 cups of water out. It looks like about the amount that should be in the "U" water trap.



Then I fired the boiler. I put a 5 gallon bucket under the union. Pretty quickly after the boiler fired I got 4 gallons of slightly-warm water out of the union. It looked like someone turned on a faucet. (Not all the way on, but a continuous flow.) I shut off the burner after four gallons as it was making a gigantic mess of my basement, splattering everywhere.



I have read all of Dan's books and I thought I was starting to understand things. But where did all this water come from? Isn't that a lot of water to be up there?



It was only barely warm -- it doesn't seem like it could have been thrown up from the boiler and shot over there (correct me if I am wrong in this thinking). It seems like it was "hiding" in the pipes and the movement of steam pushed it along to the U where I drained it. And there seemed to be more in there I didn't get out. It seems like all that cold water could explain my non-working leg... but I just correctly pitched all of the pipes near the "U" ... why didn't that water drain with the system cold when I re-hung the pipes? Does that mean this was hiding in some other pipes? Aarrggh.

niftyc_2

I'm getting 300,000

Thanks Mike. I was watching for puddle points on the risers when I raised it. There was one riser pitched wrong already (bizarrely, serving the radiator that sometimes heats). My raising the pipes may have made this worse slightly. But the other risers are OK.



The 2 foot dial goes around 2.5 times in 60 seconds, so that's 5 feet in 60 seconds. Multiply by 60 and then by 1000 and that's 300,000 for the estimated input on the boiler. Does that sound right?



Hang on what if I just look at the boiler. Printed on the boiler it says we've got 300,000 input and 240,000 output. (What an accurate rule of thumb you have.)



I will do the shut off radiators test also and report back.

nicholas bonham-carter

Cutting out the loop seal

Can you short-circuit the loop seal?

The cool water coming out would indicate trapped water, blocking air from getting out, and steam from getting where it should.

I have forgotten whether you have checked your pressure to be low. In the absence of a good low-pressure gauge, maybe the manometer method of a clear tube on a hose barb screwed into the returns of the boiler would show you the pressure in a cycle, and it should be as low as possible. Many people are rightly concerned with the return on investment in a vaporstat--a part which can cost 11 Jackson's, but I say that the reliable control of ounces of pressure, verified by an appropriate gauge is worth every penny!!!!!!!! The only systems which do not need the vaporstat are those whose boiler capacity so closely matches the amount of radiation, that the pressure never rises above a minuscule as all the steam is condensed. After all would you ever buy a car whose gearbox only has 3rd and 4th?--NBC

jpf321

Do we know where you are?

Where in the world is niftyc? I'd love to have a look if you are in NYC METRO.



ahh. Champaign, IL.. Maybe you can get boilerpro over to you..

niftyc_2

UPDATE: four of five radiators HEATING

After the removal of the 4 gallons of slightly warm water from the mains, on the next cycle, four of the five problematic radiators heated up right away. I infer that the water was causing the problem, but I still am not sure where the water was. I can't believe it! I am crazy happy!



I have to admit I still would like to know where that water was though.

niftyc_2

yes, I'm running at low pressure

I think Mike's point was that you don't want to short circuit the loop as it is preventing two feeds from serving the same main.



Yes it is low pressure. I don't have a vaporstat, so I'm not sure what pressure. I have turned down my pressuretrols so that the cut out is 1 psi and the other one is .5 psi. I have never reached the cut out of 1 psi, even in testing it because my system heats the house first and the thermostat turns off the burner. As a test, I tried to pressurize the system to the 1 psi cut out by running the burner continuously for a long time but I was not able to. When the house reached 80 degrees I gave up.

Mike Kusiak_2

Interesting!

Now it seems that you are really making progress. It appears that the section of main feeding the dead radiators is filling with condensate and not draining. I wonder if the far side of the trap section is clogged and restricting the flow of condensate back to the return? After the steam cycle is over, water slowly drains back to the boiler, draining the flooded section. Once the next cycle starts, the trap cannot drain fast enough and the main again floods and blocks steam to the risers. Kind of like a clogged trap on a sink, water eventually drains, but it cant keep up with the full flow from the faucet.



You might try disconnecting the flange joint in the center of the trap and passing a snake or wire of some sort in both directions. If the snake passes through both ways, then you will know the condensate return path is clear and that's not whats causing the backup into the main.



The only other thing I can think of is that there is a pressure differential across the trap, causing water to be held up on the problem main side until the cycle is over. Once the pressure equalizes on both sides, the water drains and the main is clear until the next cycle when it fills again. I think you have mentioned that you noticed at times that the boiler water level drops and then overfills. Might this be part of the same problem?

niftyc_2

found another low spot

Mike, sounds like you're 100% right about the water sitting in the mains. However, since I correctly pitched the section I drew in my first two diagrams, I don't see why that water didn't just all drain out when I opened the U when the system was cold. This made me think that there is a flat spot or a dip elsewhere.



So I started working farther back toward the boiler. At frist I was not able to get a good level on this main because it was wrapped in a thin sheet of bubble-wrap. So I cut away the bubble wrap and I found a section of pipe that looks much newer than the others (photo attached). I also noticed some interesting notches in the joists that seem to indicate the original main in 1904 was MUCH higher and the high point of the original main was at the boiler as Dave said it ought to be. See how the notches get lower at east joist?



But the new-looking pipe is almost level. (I'm sorry it looks like I measured the pitch wrong in the last two diagrams because I was measuring the insulation.) I tried to raise it with my "kicking several 2x4s" method and I did not succeed. The part circled on this picture just seems impossible to move. I also screwed up the pitch of the other section that I already fixed. The whole thing works like a see-saw. In my last post I said raising the elbow of the main was easier than I thought -- this is much harder.



Mike, I tried to investigate your blockage theory but I can't get the union at the pictured "U" open far enough to put anything down it. I can budge it about a millimeter. I am using a crowbar.



I ran the system with the union open and removed two more gallons of water before it started to turn hot. Then I shut the union. 3 of the 5 problematic radiators then heated nicely and I was hoping the others would too but then boiler then shut off on low water. I guess I took out too much or the condensate is hanging around in the mains.



I drew a new diagram showing the state of things and the new main section. I also borrowed a digital level so I marked the pitches.



It seems like the condensate must be pooling at that new-looking section of pipe and just beyond it. However the radiators served there seem to work very well, which is strange. Maybe I am overthinking it.



jpf I am in Champaign, IL.

Abracadabra

screwed up level on main

The pitch on that main is so messed up.  If you cannot repitch it properly, you may have to pipe in some drips and tie into a return.







Now that I look at your  new diagram, I'm thinking that the loop at the end of the one main was put there for a reason.  They might have been trying to convert a parallel flow main to a counterflow? I haven't seen any pics that show me the return, so i'm assuming the main handles the condensate.

Mike Kusiak_2

Measurements

Could you put some dimensions on your diagram showing the lengths of each section of pipe? It would be helpful in that you have pitch per foot marked, but we no idea of the relative lengths of pipe involved.



As far as testing the clogged trap theory, can you try opening the flange union shortly after the end of a steam cycle to see if gallons of water are being held back there, before it has a chance to slowly drain  through a possible blockage.



How are the mains tied into the boiler? Do you have a proper header and equalizer? Maybe a photo of the boiler and piping would help