mysterious improvement in steam heating system

chapinpark

I moved into a steam heated house this past summer, and when heating season came around, the system was incredibly loud - and I say this is as someone who grew up in a house with steam heat. A loud series of clangs lasting 5-10 minutes about 6 or 7 times per day. I tried some of the things suggested on this site, like lowering the pressure of the system, and that helped - but not all that much. Then we just went away for about 10 days, during which time we lowered the temperature of the house to 50 degrees. We got back a few years ago, turned the heat up, and now it is mysteriously quiet - no banging at all for the last four days. We had never gone a half day without banging before.



Obviously, I'm happy about this - but also would like to understand why it happened, so that I can have an idea of the cause of the banging if it returns. It seems to count against some possible causes, like incorrect pitching of the pipes and clogged vents, since neither of these problems could magically have been fixed while I was away. Any suggestions for what could have caused the banging that could have been fixed by 10 days at a low temperature?



I'm also now nervous that any 'improvements' I was planning on making - like replacing some of the air vents on the radiators - will upset the delicate balance of the system and return us to the banging system of last month. Replacing air vents couldn't mess things up, could it?



Thanks in advance for any help you can give me. This forum and web site is a really amazing source of information.

jumper

if you're happy

Leave it alone. Lot's of things could have happened. For example the old house may have moved to eliminate a low spot. Or standing water finally dried out.

EBEBRATT-Ed

banging

Don't want to break your bubble but these problems never "heal" themselves.

I would suggest:

 posting pictures of the near boiler piping

Check steam, condensate lines and radiators for proper pitch

Keep your eye on the boiler pressure gage. You should be able to heat the house without building pressure

Check for a normal water line about 1/2 a glass and check for a steady water line.

The water line shouldn't surge excessively while steaming.

If (when) the banging returns try and determine where it comes from and when it happens, beginning middle or end of cycle.

Good Luck,

Ed

Hap_Hazzard

First Question

Is the system working?



The parameter most likely to have changed while you were away would be the water level in the boiler. If it was too high that would put water in places where it doesn't belong and the steam would have to punch it out of its way and you'd have water hammer. Too low and you can get steam in the Hartford loop and that can cause banging when the condensate rises up and slugs back into the equalizer. If there's an automatic water feeder, that might have activated while you were away and restored the normal water level and things would have gotten quiet again.



You'll notice I'm using a lot of "if"s and "might"s here. That's because I'm guessing. To get a more useful answer and suggestions you can act on we're going to need a little more information about your system. Is it one-pipe or some variety of a two-pipe system? Do you know where the water level was when you initially fired up the boiler for the season? If so, is it different now? Can you show us some pictures of the boiler and its associated piping?



Finally, although you are familiar with steam heat, one cannot assume you know all you need to know about your present system. There are many different types of systems, and to a great extent, every system is unique. There might be certain routine maintenance tasks you should be aware of if you're not already. We can point these out to you, as well as any potential problems you should be aware of, if you provide us with the information we need. We really don't mind if you tell us everything you know about your system and post pictures of your boiler, all the visible piping, and each and every radiator. We love this stuff, and some of these guys here know an awful lot about it. You might be surprised at what you can learn from them.

chapinpark

further information about the system

Thanks to all for the replies. By the way, I certainly didn't mean to imply that I know a lot about steam heat by saying that I grew up in a house with steam heat - I just meant that I had some idea of the sounds that a reasonably well-tuned steam system will make. I know next to nothing - I'm trying to educate myself by reading some of the books recommended on this site.



The system is a one-pipe steam system. I will take some pictures of the near boiler piping and post those soon.



The suggestion that this is due to a change in the water level is intriguing. Before leaving town - when all of the banging was happening - the water level was right near the stop of the glass when steaming. Now it appears to be lower - though I can't say exactly how much lower, because the glass is so dirty. (I plan to have it replaced soon.)



If the water level dropped significantly while I was away, would that suggest a leak somewhere in the system? It is an auto-fill system.



I agree with Ed that whatever problem was there before seems likely to re-appear at some point - my hope was that the manner in which it seems to have temporarily fixed itself would give some clue of the underlying problem.



Thanks again for all the help -

Hap_Hazzard

Water Level

You can clean the gauge glass. If you don't have a bottle brush the right size, or you don't want your wife to yell at you for using it, you can roll up a sheet of paper towel and push it through. It's a lot easier than changing it because you have to cut the new one to the right length.



The condition of the glass does tell us something useful: your boiler needs a skim.



Ordinary rust and scale sinks to the bottom. Oily sludge leaves a film on the walls of the boiler and inside the gauge glass. It also forms a film on the surface of the water that makes it hard for the steam to escape, causing surging, foaming, carryover (i.e. spraying water droplets into the supply piping) and generally wet steam. The only way to remove this gunk is to skim it off the top of the water. There is an article on skimming in the Library.



http://www.heatinghelp.com/files/posts/13907/Skim%20Article%20OH%20June%202009.pdf



A change in water level in a short period of time does indicate a leak. Normally a residential one-pipe steam systems shouldn't lose more than an inch or so over an entire season. This is something you should be concerned about. A fluctuating water level can do serious damage to a cast iron boiler.



That automatic water feeder should not be maintaining your water level. Water feeders are a safety device. If it's set up right it shouldn't activate until the water level is dangerously low. You do not want your water level to get dangerously low on a routine basis. Aside from damaging your boiler, you're running the risk that the water feeder's valve will fail to close, then you'll have a flooded boiler and possibly thousands of dollars in water damage when water starts coming out of your radiator vents. Water-feeders are notorious for flooding boilers--and houses--when people abuse them this way.



Maintaining the water level is your job. It's one of those chores you have to accept when you heat with steam. You should check it at least once a week and top it up if it's a half inch low. If you have a float-type low-water cutoff, you should be blowing it down every week to keep it from getting fouled with sediment and to make sure it cuts the burner as it should.



But that's routine stuff. Right now you need to find out where you're losing water and get it fixed before you wind up trying to limp through a historically severe winter with a damaged boiler. Hopefully the leak will turn out to be in the wet return and not the boiler itself.

chapinpark

photos of boiler & piping

Well, as Ed predicted, the water hammer is back, and with a vengeance. I've also noticed that the water level seems to be near the top of the sight glass again, and varies a lot over time. I'm wondering whether part of the problem stems from dirty water - but what do I know.



Also, two radiators just began leaking through the intake valve. Neither has shown any sign of leak before. It seems a bit odd that this should happen by coincidence, but I'm not sure how all of these issues could be connected.



The photos of the boiler and near boiler piping are below - I was not sure quite what to focus on, so apologies if some of these are irrelevant, or if there are other parts I should have taken pictures of. Thanks for all of your help!



Also, I'm in South Bend, Indiana. I don't think that there are any Indiana contractors listed on this site. Does anyone have any recommendations?



- Jeff

chapinpark

one more thought

Is it possible that the automatic water feeder is set so that it is automatically keeping the water level too high? And is there a way that I can check this?



Again, thanks for your help. - Jeff

EBEBRATT-Ed

sorry your trouble returned

hard to tell from pictures but the high water level could deffinately be a contributing factor in the banging. try running with 1/2 a sight glass of water. check piping and rads for proper pitch, especially the ones that are leaking. is that where the banging is coming from?

EBEBRATT-Ed

whoops dbl post

Hap_Hazzard

May be part of the problem.

This looks like a re-branded Utica boiler. The supply ports are on the sides which puts them very close to the water line. If the water level is high, that puts it even closer to the outlet ports. But that's not the only problem. I mentioned it before when you commented on the dirty gauge glass, and your comment about the water level varying over time is another indication: this boiler needs to be skimmed.



The only steam pros anywhere near you that come to mind are in the Chicago area, but if you call around and say that you have a Bryant boiler that needs skimming, see what kinds of questions they ask you. If you find someone who seems to have a clue, try to set up an appointment when you can be there.



Skimming is a very time-consuming task, so if you can be there, with a pot of coffee and maybe a donut or two, you'll have plenty of time to chat. If you're lucky he'll walk around and check out your whole system and give you some pointers. If he does, pay attention, take notes, nod a lot and ask good followup questions. If he's a typical steam guy he'll be very enthusiastic about learning about your system and sharing it with you. See if he mentions this site or if he's attended one of Dan's classes. Treat it as an opportunity to learn about your system and interview someone to take care of it in the future.

chapinpark

skimming

Thanks to both of you for the advice. I've tried to find someone like this in the South Bend area, but with little luck so far. I will keep trying. It would be great to find someone who knows what they are doing to walk me around the system and show me what's going on.



If I can't find anyone, is skimming the boiler something that I could, with more study, do on my own? I agree that it really seems like this needs to be done.



The banging is almost all coming from the basement pipes - and so far they seem to be pitched correctly, though I have not managed to check all of them yet. So I think that the water level might be at least one of the causes.



I did have one more question about the pressure in the system. I have set the cut in to 0.5 psi, and the cut off to 2 psi - but the gauge on the boiler lists the pressure, unchangingly, at 4.5 psi. Is this likely due to the fact that it is a 0-30 psi gauge which does not do well measuring low pressures precisely?



I've also noticed that despite there being two mains, there seems to be just one main vent, which looks pretty ancient - so I am sure that is not helping.



From the pictures, does the near boiler piping seem to be correct, or is it too hard to tell?



Thanks again for all of the help. It is much appreciated. - Jeff

Hap_Hazzard

Near Boiler Piping

It's not right, but I think you can live with it if you can get the surging under control.



The problem is that there is no true header, and if you look at the branch that comes off the main between the two risers, that's a big no-no. When steam comes from the two risers, it has to converge at the tee, and this prevents water that comes out of suspension from returning to the boiler, so it accumulates until the steam can't get through without building up pressure and then slamming its way through. This is probably responsible for the noise you're hearing.



The one thing you have going for you is that the risers extend straight up for what looks like about four feet. Under optimal conditions this will allow most of the water droplets to coalesce and fall back to the boiler before reaching the mains. Currently I think the surging that's caused by the oily surface film is putting too much water into the steam flow. Once you get that under control I think it should be reasonably quiet as long as the cycles are short enough to allow that section to drain before it chokes off the branch at the tee.



We normally don't recommend skimming as a do-it-yourself procedure, but then, I did it, and I'm not the sharpest tool in the shed. I do have a mechanical background and an almost pathological curiosity about things I should probably keep my hands out of. If you're similarly afflicted we might be able to help you through it.



Right now it's too cold out to get involved in this, so take your time, gather information and read up. In addition to the skimming article I posted above, check your boiler manual to see if it has any skimming instructions. I have no idea where the skim port on a Utica or a Bryant is, so the manual will be a big help there if you have one. If you don't or it doesn't have this information in it, give us the model number and we'll try to find it online.



You might also want to order some of the books available here. I got almost all of them, and they're not only loaded with useful information but a real joy to read too.



Keep beating the bushes for a reliable steam pro too. There's probably one out there beating the bushes for customers; you just need to find each other.

Steamhead

It's a Dunkirk actually

and, like every Dunkirk that has been posted recently, is piped totally wrong.



Not only does there not appear to be a header, but the single steam pipe leaving the boiler looks like 2-inch instead of the 2-1/2-inch the manufacturer wants. You'd think installers would know how to read and follow a piping diagram, but nooooo. You can't fix stupid.



Dunkirks are very sensitive to improper piping. This boiler needs both 2-1/2-inch risers feeding into a 3-inch drop header. The tops of the risers must be at least 24" above the highest possible boiler water level. This will keep water from getting into the steam piping and causing the noise you hear.



Have you tried the Find a Contractor page of this site? If you strike out there, try The Steam Whisperer (Dave Bunnell) in Chicago and see if he'll come out. He knows very well how to pipe Dunkirks.

Hap_Hazzard

Glad you stopped by

You know, I can never tell those Dunkirks and Uticas apart. They both have these five model lines that look exactly the same! I guess you get to know these things after you've worked on a few hundred of them.



I think there is another riser over on the other side, but there's a bullhead tee between them--one of your favorite things!



I was trying to remember where Dave Bunnell was located. I knew he was out there in the Hinterlands. He'd be really lucky if he could get Dave to come down there for an afternoon.

Steamhead

There might be a second riser

or it might be a drip... hard to tell from the pics. But it doesn't matter- that boiler is piped wrong. 

nicholas bonham-carter

Skim port

The best skim port would have been a tee on the outlet of the boiler, but that would be challenging to engineer in this weather.--NBC

chapinpark

thanks

OK, thanks for the advice. I will try lowering the water level and see if that makes any difference. Hopefully it will - otherwise this water hammer will drive me (and my family) crazy....



And if anyone can recommend someone good in northwest Indiana, please, by all means, let me know.

Bob Gagnon plumbing and heating

I Agree

The water level may be too high, shut it off and maintain water level about halfway up the glass. I didn't think a Bryant Boiler was a Utica/Dunkirk?? One other thing to check is have you shut off any radiators with the large service valve near the floor, that's a big no no and can cause banging and vents spitting.



Thanks Bob Gagnon

chapinpark

question about turning off radiators

Funny that you say that, Bob, as I have just turned off the inlet valve to two 1st floor radiators - because they had started to leak, and I'm waiting for someone to come and replace the valves. I'll re-open them when fixed - but I'm puzzled about why that would cause banging. Is there an easy explanation that someone who has only read 'We've Got Steam Heat!' would understand? Thanks -

Hap_Hazzard

Supply Valves

When they're in good working order they can be used to shut off radiators. What you should never do is close them part of the way to try to throttle the flow of steam.



In a one-pipe system, the valve not only has to allow steam in, but also let condensate (water) back out. If the valve isn't fully open, the flow of steam prevents the water from exiting, and it builds up to a point where it blocks the steam from entering, until the steam builds up pressure until it blasts through, making the radiator sound like somebody hit it with a big hammer.



With older vents the disc often becomes so hardened and encrusted with rust and scale that it can't close all the way even when the hand wheel is turned as far as it will go, so it behaves like a partially open valve.

Bob Gagnon plumbing and heating

Just Tighten

The packing nuts, don't replace the whole valve, you'll probably have to replace the part that goes into the radiator too.. When the valve is closed steam makes its way past the 100 year old valve, but the condensate can't make it back out, it causes banging and vent spitting, I didn't beleive it at first either, when Dan first told me, but I have seen it enough times to know that Dan was right, he usually always is. Open your valves, and tighten the packing nuts, only a little.



Thanks, Bob Gagnon

chapinpark

Packing nuts

Thanks for the advice. I knew not to leave the valves half open for the reason you mention - I closed them all the way to stop leaks. But the radiators are still heating which I take it indicates that the valves are not really fully closed since steam is getting in. How would I go about slightly tightening the packing nuts?

chapinpark

sorry, dumb question

I just realized what the packing nuts are. Unfortunately, tightening them a bit does not stop the leak. Maybe I will try some teflon tape.

Bob Gagnon plumbing and heating

Leave The Radiator Valves

All the way open. Are the valves leaking where the stem goes into the packing nut? You should get some graphite packing material, it looks like string, from a plumbing supply store. Let us know if the banging goes away with the valves open all the way. You will probably have to drain some water from the boiler when the radiators fully drain, as radiators will often hold much water.



Thanks, Bob Gagnon