fixed the big problem, now what?

bradslees

OK -- to be as succinct as possible:



First winter in my new ~75 year old house. One pipe steam with an ~10yr old gas boiler. There are two mains, each with a separate return. The radiators are fin-tube style. On the front side of the house the main and return run through the garage. The back side runs through the basement and used to be identical (75 years ago) but when the basment was finished (several owners ago), they eliminated the return (and the vent) and swapped in a steam trap and a 3/4" copper wet return that ran down along the baseboard and back to the boiler. When we fired up the system for the winter the back side main was banging like crazy. Long story short, that trap and return were not returning condensate fast enough, the low water cutoff would trip and the autofeed would add water to the boiler. This meant too much water in the system, which gave me the banging. I had my plumber get rid of the trap and add a vent and that essentially solved the problem.



New (related?) problem is that the radiators are making a crackling sound. At first I thought it might be a pretty normal noise from them warming up, but when I listen closely it really sounds like water hammer, but just at more of a whisper. This noise is coming from almost all the radiators, not just the rear main, like the previous sounds. It also seems to be getting worse (louder and more consistant) though that could just be my imagination. I would probably just ignore it if it weren't for the fact that this morning it woke up the baby at 4:30 AM when the thermostat kicked on for the morning. Since I can't swap out the baby for a heavier sleeping model, I'm hoping to fix the noises, but I'm a bit overwhelmed by where to start.



I already checked the pitch on the radiators. They seem OK. I also plan on swapping out the ancient Durst A883 main vent on the front side and the brand new but undersized Vent-Rite 35 the plumber installed on the rear. Replacing all the vents on the radiators is also on my list because they are mostly old and seemingly randomly sized, but I have no idea where to begin with that process (i.e. which vents to use and how to tell if it's helping).



Other suggestions or guidance is most appreciated!

MDNLansing

Questions

What pressure is your system running at? Whats the cut out and cut in?



What does the water in the gauge look like when steaming? Is it sitting still, or bouncing?



You should certainly replace those main vents. Get a good quality vent like a Gorton #1 or #2. Hoffman makes nice vents as well.

nicholas bonham-carter

First on the list

Eliminate your setback first, and get some Gorton 2's on those main vent locations.

Make sure your gauge is accurate and make sure the pressure is not too high. The pigtail may have become clogged preventing the pressuretrol from doing its job.--NBC

bradslees

answers

i haven't touched the pressure since i moved in. the slider on the front is set between the 0.5 and the 2, probably closer to the 0.5 (no markings in between those two values). Inside, the differential is set to 1. Next time I hear the boiler kick on I will go down a look at the dial on the unit to see what the pressures read while it's running. I've been leery of messing with the pressure because I don't want to screw anything up -- is there any danger in changing those settings? Also, is there any point in messing with the pressure before I change the vents? I assume that changing the vents changes the optimal pressure?



The water in the gauge does bounce around a little when steaming, but it doesn't seem like anything crazy to my unfamiliar eye, just what I'd expect from a pot of boiling water.



I think I'll order the vents tonight!

JStar

Noise

Was that old trap serving a purpose?



Any before and after photos?

bradslees

pressure

I checked it out. Here is a pic of my pressuretrol. The system cuts out just shy of 3psi if I go by the gauge. It turns back on at around 2psi. So it seems like it's set at 2psi with a differential of 1? You can see in the pic that the dial seems to be set below 2, so I'm not sure if I should believe the dial or the gauge. In either case it seems like I should lower the pressure? My concern is that the boiler will short cycle when I do that since it only took a few minutes (maybe 5?) to go from not making steam to shutting off at 3psi.

bradslees

the trap (pics)

The trap was put in between the old riser and the new wet return line. I presume that the person that did that had a good reason to at the time, but I asked a few pros and they all agreed that you don't need a steam trap at that point. Since it seemed to be the source of the slow condensate return problem, I opted to just take it out.



see attached pics for before and after.

MDNLansing

Good Start

First off, it's good you're taking care of the basics first. Once these little things are ironed out, you'll have a good idea of what to address next. The pressure, vents, and water quality might not be the cause of your problem right now, but its best to square these away before trying to fix other things. Some systems are real sensitive to these things, and they're easy to fix.



First things first, replace the vents. You want the good new vents in place before messing with the pressure. I wouldn't install additional ones just yet. Just replace what you have, square away the pressure, then add more vents if needed after that. If you do find that one vent isn't enough, you can install multiple vents on an antler using the existing tap. Search this site for vent antler or vent menorah for ideas on how to build them. They are very simple and easy to make with readily available fittings from most any hardware store.



As for the pressure. First, get yourself a good new low pressure gauge. Several online merchants sell 0-3 psi and 0-5 psi gauges. They can be hard to find in plumbing supply stores but it's worth calling them too. When you get the gauge, take the copper pigtail off and clean it. Make sure there are no obstructions or gunk in it. Then, install the new gauge and pressuretrol with the current settings and record the pressures again. This will tell you what the cut in and out pressures are. The pressuretrol is mechanical and the actual limits will vary from what is printed on the scales. Just take some pictures so you can always return to the current setting. Adjusting it improperly could cause you to short cycle, but you can always go back to where you are now to stop it. Tweak the pressuretrol settings to get the cut in as close to .5 and cut out to 1.5 or lower. Don't go by the scales on the unit, just adjust them down, run a cycle, and record the values from your nice new gauge. So, if lowering the bar 1/4" was too much, raise it back up an 1/8" (you get the point). You'll be able to fine tune it to as low as it will go. They aren't real precise so getting close is the best you can do. Again, in the end you want a cut out of 1 to 1.5, and cut in of about .5.



As for the water, a few boiler pics would help. If you say the water bounces a little, it might be a problem or it might not. Depending on how the near boiler piping looks it might be OK. On the other hand, even an inch of bounce could cause some issues. Posting pictures will let other people here see how crucial it is, and will get you help to skim it if needed. It never hurts to clean and skim a boiler neglected boiler, but if the piping is real bad it might be a must in your system. Pics will get you the right help. Take a few pics that include as much piping as you can fit while still keeping a good resolution. Make sure at least one pic shows the near boiler piping and boiler from the floor to the top of all pipes and vents.

bradslees

two things

1) I'll replace the vents, for sure. I ordered a Groton #1 for each main to start since I have 3/4" fittings already and I can just screw those on without changing anything. Should arrive for the weekend. But what about the radiators? There are definitely some broken and crappy vents, though probably some work. Is there a reasonable approach to this? I'm not opposed to just replacing them all (9) if it will give me a fresh start, but wouldn't know what to replace them with.



2) Replacing the pressure gauge seems like a good idea, but reading other posts it also seems like i need to keep the old 30psi gauge for the code. My pigtail and gauge also seem to be in a somewhat unconventional arrangement looking at other posts (see pic). One end is buried back inside the boiler. Any suggestions for how to proceed with that? Given that I've never plumbed anything in my life, should I try this myself?



Thanks for all the good info.

BobC

Venting

calculate the volume of each main and then install enough venting to vent all the air in 2 minutes or less. A Gorton #1 is good for 0.33cfm and a #2 is 1.1cfm.



Get that pressure down and make sure the pigtail is clear.You won't really  know what the pressure is until you add a low pressure gauge to the the one you have now and the low pressure gauge has to have a pigtail between it and the boiler.



On the radiators, what kind of vents are on them now? In general you want to vent the mains very fast and the radiators slowly, that is usually the best way to balance a steam system. Very large radiators or ones on upper floors may need faster venting. Be careful to vent the radiator close to the thermostat so it heats up at the same rate as the rest of the building.



The problem comes when your faced with having to replace a bunch of vents and not knowing which vent to use. They are not very expensive but you would rather not guess wrong and have to change them out and just have them laying on a shelf. You can use Hoffman 1A adjustable vents (0.020 to 0.145cfm - some complaints on some systems) or Ventrite adjustable vent (off-0.020 - 0,083cfm - very good but pricey) or  Note the Ventrite #1 does have an off setting and the others do not. You can try the Maid-O-Mist 5L that comes with 5 different orifices that let you go from 0.28 to 0.341 cfm, That stops the vent swapping game and they are modestly priced.



http://www.amazon.com/Maid-O-Mist-0220-5L-Steam-Angle-Radiator/dp/B003DV3AGE/ref=sr_1_2?ie=UTF8&qid=1386247145&sr=8-2&keywords=maid+o+mist+air+vent



Bob

mcsteamy

A random idea...

Try this:  What radiators you have is a little confusing to me.  Baseboard copper fin tube on steam?  Really?  Try lubricating any points of contact between the radiators and the supports with a little WD40, and possibly putting just a little torque on one of the problem radiators by jacking it up in the middle just a bit.  See if this changes or eliminates the noise.  You can get some really nasty thermal expansion noises if paint and years of wear and tear are causing excessive friction.  This can particularly be a problem in old single pipe radiators where the top draw rod meets the section, and sometimes even at the bottom nipples.  You might have something similar going on here. 



Now, if from a cold start you are shutting down on the pressuretrol in 5 minutes, you may have a venting problem.  Although, with fin tube, you're going to hit pressure a lot quicker than with cast iron.  Gorton #1s aren't perfect, but will do a lot better job than what you have now.

bradslees

venting

Thanks for the info Bob. I'm sure that if I did the calculation I'd need more than just a single #1 to vent all the air, but as a first pass I'm just going to swap the current vents for single #1s. Anything else would be slightly more involved, which will have to wait.



The current vents on the radiators are a mishmash of everything. Some circular vents, some cone-shaped vents, some adjustable, some broken. That's why I'm inclined to just swap them all and start over. The complication may be that because I actually have fin-tube radiators (which I'm starting to realize is unusual for a one-pipe steam system) the vents have to be straight and not angled. Those adjustable vents seem to only come as angled. If you could recommend and slowish angle vent I think I would just buy 9 of those to have one for each radiator, and then also buy 2 or 3 faster vents to have in my pocket if I need to swap something out. Probably not the cheapest way, but maybe the easiest. Thoughts on that?



Last question -- if the pigtail is attached inside the boiler (see pic on previous post) how do I make sure it's clean? I wouldn't know how to take it off to clean it...

bradslees

yes, fin-tube radiators on one pipe steam

As you say, I'm starting to realize that having fin-tube radiators on a one pipe steam system is unusual. They're not baseboard, though, they are recessed in the wall and covered with removable panel-style covers. Not sure why they chose to do that 75yrs ago when they put the system in. In one sense it's great, because I have little kids and there are no blazing hot radiators to burn tiny fingers, but it's also a little hard to find good info.



To get to your point, I read some other posts about expansion related noises, but this is definitely related to water in the radiators. I can hear the sloshing and gurgling in the pipes as well as in the vents.

nicholas bonham-carter

Increased venting

Leave the rad vents until later, and replace what you have now on the mains with Gorton 2's. You can't over vent mains and you will be more certain of having enough.

Get a 0-3 psi gauge, and put it on next to the pressuretrol, so you can get the pressure maximum down.--NBC

mcsteamy

Gotcha...

Unusual is right!  If it isn't at all related to expansion noises, I would say the excessive pressure comments are on the mark.  The sloshing sounds indicate condensate is not making it back out of the radiators.  I can't say I'm familiar with the system at issue here, but I would venture a guess it was designed to run on very low pressure.  Odds are, excess pressure is holding the condensate back.  If there is any room left to crank down on the pressuretrol, crank it down.  If, after confirming that it works right, you still have issues, it might be time to invest in a Vaporstat so that you can run on a few ounces.



EDIT:  I've been thinking about this system, and odds are, it might follow some slightly different rules.  Can you post pictures of the radiators and other parts of the system so we can get an idea what we're dealing with?  I just can't picture what the radiators look like.  If this was an original single-pipe install with concealed fin-tube radiator, it was very, very far from the norm.



Also, when you shut off on pressure, are the radiators hot, or still freezing cold?



Fin tube is a goofy system for cast iron, and there is an ideal way to run it if the system is still good and air-tight.  Because it's either all on or all off with no thermal mass in the radiators, this might be a good candidate to adapt to vacuum operation down the road.  It is remotely possible it was even designed this way in the first place.  But, the only reasonably easy way you could pull this off (since no one makes a vacuum vent anymore) would be with Maid-O-Mist vents adapted to vacuum operation (which someone else here has done) and using either a Hoffman 76 main vent (the only vacuum vent left) or radiator traps as main vents (also adapted to hold a vacuum).  The idea is that steam boils at, say, 180 degrees in a vacuum, meaning you get cooler steam, less temperature swings, lower fuel costs.  Somewhat of a pain in the neck to get it all working, but it might be worth taking a stab at. 

bradslees

will post pics later

I'm happy to post pics -- I appreciate the help. I'm at work now, though, so it will have to wait until after I get home (and more than likely, until after the kids go to sleep). I'll get something up tonight, though.



in the meantime i was able to find a catalog that at least has a pic of what the covers look like, for your reference. Mine are actually nearly flush, though, they are a flat panel, not a box. Inside the convector looks like what I'd imagine a typical baseboard unit does, except the riser comes up out of the floor, and the convector is at a 90 degree angle to that. the vents are at the end closest to the riser. the far end is just a dead end.



i do keep trying to think about why they would have done it this way. not having owned a house before, or given much thought to steam heat, it didn't even occur to me that it would be unusual. like i said, it's a bit more child friendly, and you don't have radiators on the floor/ maybe it was just cheap! but who knows...



to get to your other point -- do you think it's sensible to just crank the pressuretrol all the way down and see what happens? is there any harm in that? the system does got hot as is, it's just noisy.

bradslees

0-3 psi gauge install

would i put on the new gauge by adding a Tee at the top of the pigtail and then putting the pressuretrol on one branch and the gauge on the other? is that a do-it myself kind of job?

(for a reasonably handy, but completely inexperienced person...)

BobC

Thats what I did

You should be able to buy whatever 1/4" npt fittings you need at a decent hardware store. I am going to use a nipple to get the 0-3 gauge a little high when I get around to it.



Bob

mcsteamy

Yes.

Crank it down if there is any room to go lower.  Won't hurt anything.



Again--are you shutting down on pressure before the convectors are hot all the way across?  5 minutes sounds low, but with 75 year old fin tube convectors that probably have a tenth the thermal mass and volume of radiators, who knows..

bradslees

sure...

I'll try cranking down the pressure as low as it will go. Just so I know -- if that was going to cause problems, what would they be? i.e. what should I be on the lookout for?



my guesses:

- radiators not getting hot enough because the steam can't get in at the lower pressure

- short cycling burner because it keeps hitting the pressure max

- if the short cycling means the burner can't fire enough to get steam, cold radiators



yea?



the 5 minute figure i gave wasn't from a cold dead start, but was from being off-cycle. meaning the boiler had been off for 30 minutes or an hour or something like that. your comment also makes me wonder if the system is just designed to run slighly differently because of the fin tube elements. like maybe they get hot very quickly, but also cool down quickly, so the system runs more often but for shorter burns? the house does tend to hold heat pretty well, though, so who knows...

mcsteamy

If

If the burner cycles on the Pressuretrol because everything is full of steam that isn't a problem.  That's proper operation.   What we don't really want are radiators that are not hot all the way across, the stat unsatisfied, and the burner cycling on the Pressuretrol.  Then we need more venting, either on mains or radiators.



Unless something is screwed up, it shouldn't affect heat.  Say you have 1.5 pounds in.  The convectors will condense steam and put out heat until pressure drops to .5 pound.  Burner will fire, steam will come up, and heat will come out again.



A 400 pound steam radiator that puts out 20,000 BTU when hot across is a different animal from a fin tube that does 20,000 BTU.  When the system starts, it will take a long time to warm up all the heavy metal.  The convector, on the other hand, will be able to dump out that 20,000 BTU almost immediately.  When the boiler shuts off, the fin tube convector will cool off in minutes, whereas the heavy cast iron radiator will continue to dump stored heat for an hour.  

bradslees

so then

is it totally just bonkers that I have fin-tube radiators on my steam system? i mean, i'm stuck with it either way, but it sounds like maybe i'm spending money heating up my basement way more efficiently than i'm heating up (and maintaining heat in) my radiators.



one thing i will say is that, the annoying noises aside, the house does get warm and stay warm reasonably evenly, so maybe the old timers knew what they were doing. I, on the other hand, have no idea!

mcsteamy

Not bonkers,

Just not very common, but apparently this system was designed that way from the outset.  75 years old is actually very new for a single pipe system.  Odds are you will benefit from a big main vent and getting the pressure down as a start.

bradslees

finally, the pics

first, off -- i turned the screw on the pressuretrol all the way down. it actually popped out of the coil at the bottom, so had to screw it back in a little, but it's as low as i could get it. i'll see how it's working, but i will say that i didn't hear any noises through the night last night and the house went from 66 to 69 at 4:30AM, as programmed. I'll keep you posted.



Now, here are the pics of the fin tube radiators on my one pipe steam system. sorry it took so long. I'm actually really glad you asked me to do this, because it made me realize that my recollection of what these things looked like behind their covers wasn't particularly accurate.



- as the steam comes in from the riser it gets split into 4 small diameter (1/2"?) copper tubes that run the length of the unit. There is a vent at the far end which i assume means those 4 pipes come back together at the end and are all vented together. On some of the units the vents have elbows and on some they dont. There's also a metal bracket at the far end mounted on the wall to help keep things pitched. In some cases those were broken or sagging, so I just shoved a cut piece of 2x4 under there to prop the far end up.



You'll see there's also a damper on top of each unit. I'd been keeping those in their 1/2 way position (45 degrees), but now switched them to all the way open. My assumption is that they regulate the draft caused by the warm air exiting the top of the exterior grille (which presumably regulates the amount of room air drawn in from the bottom, which is how I'm guessing this thing works.)



What ya think?

mcsteamy

Wow!

Forgot to mention don't turn the Pressuretrol so far that it breaks.... Oops.   

Hopefully lowering it helps the noise. 



With those tiny pipes in those convectors, low pressure is probably your best friend. As far as the rate of venting, if you shut down on pressure before the convectors are hot all the way across, and AFTER increasing the main venting, turn up the Vent-Rite's a notch at a time. Theoretically, I would think you would want to have the convector hot all the way across as quickly as possible, without causing hammering.  You're also going to want to set your stat to run more like a furnace--probably two or three cycles per hour since once the heat is off, it's gone.



Re: your vents, the convector in the photo, at least, has a Vent-Rite adjustable vent on it, which is a great vent and if it works (i.e. the convector gets hot) does not need to be replaced.  Sounds like you have a "dual control" opportunity here--you can dial down the heat using either the adjustment knob on the vent, or the "damper" on the enclosure.  So if you get a racket even after cranking pressure down, just try turning down the knob on the vent-rite one setting, which will slow the entry of steam into the convector on a colder start (and less heat, of course, but opening up the damper might help with that).

bradslees

not much happened

I actually didn't turn the pressuretrol very far at all before it came apart, which I think means it was already set essentially at the lowest. That is also supported by my results: nothing changed. The system cut out on pressure at 3psi (on my big gauge). I ran up and felt the radiators and they were all hot on the covers, but I didn't open them up to see if they were heating all the way across.



Since I don't think it's a good idea to start adding a new gauge or pressuretrol right before the winter, I guess I'll have to focus on the venting for now. My main vents should get delivered today and after I see what that does, I'll tackle the radiator vents.



Some of the units have those adjustable valves and some don't -- and I think some of them work, and some don't. Do you think I should replace the broken vents with the adjustable vents? And for the adjustable ones, is it better to start small and open them up, or start with them wide open and dial back?

BobC

Start low

Convectors can produce a lot of condensate because of the large surface area so I would think they would want to vented at the slow end. One of you pictures show a Ventrite # 1 which can be adjusted from off (at 1) up to 0.083cfm (at 8). A Hoffman 1A starts out at 0.02cfm and gets up to 0.10cfm at 3 and 0.145 at 6.



In general you want to vent the mains fast and the radiators slowly.



Take any vents you can't blow through and try soaking them in CLR or boil them in white vinegar for 20 minutes to see if you can free them up. Don't use the USAV vents they sell at the big box stores, they cause more problems than they solve.



Bob

bradslees

update

hey gents-



just thought i'd update you on my current (lack of) progress. I did swap in the Gorton #1s on the mains which, while it felt very fulfilling, didn't make much difference with the crackling convectors. (I've stopped calling them radiators now that I know how special I am to have them... I'm looking on the bright side). I would imagine that things are getting hot faster now, which is definately a good thing -- and hopefully saving me some fuel.



Anyway, I guess replacing/cleaning the convector vents would be the next step, mostly because it's easy. though from all the pieces we've put together, I'm starting to think that it's actually a system pressure issue and my pressuretrol isn't letting me crank things down to where they need to be. The other possibility (which I'm realizing as I read bits of Dan's book in my spare moments) is that my near boiler piping is not correct and I'm getting wet steam. I wouldn't be shocked by this because the boiler was squeezed into a tiny little space when they finished the basement and I doubt that following the manufacturer's specs was at the top of their priority list. right off the bat i see that the pipe out of the boiler is a 3" pipe that gets immediately reduced down to 2. i would doubt that that was the recommendation.... i attached some pics of the system if you want to chip in 2 cents on that one.



If you guys have any more suggestions, or any diagnostic things I could do to really figure out the source of the problem, I'm all ears. Otherwise, I'm getting the feeling I'm going to have to live with this until the spring, when I can install a new pressuretrol and gauge.

bradslees

is it worse?

Hey All-



I think after all that we talked about, swapping out my main vents for Gorton #2s, my seemingly ineffective attempt to lower the pressure, and a tiny bit of tinkering on the convectors that had adjustable vents, the noises in the system are actually worse. It's still nothing approaching the sledge hammer noises I started with before removing the stuck trap, but the clicking and gurgling is now more like a pinging and tapping. It's not just on the convectors that I tried to adjust, either. What gives?