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Water Draining Sound 2-Pipe Steam

Moved into a house 3 years ago, has steam heat, had no idea what I was getting into. The first time we fired it up, the water hammer was unbearable. Called the steam guy, he did some stuff, charged us $1,000 and didn't fix anything. Called another guy, he fiddled with something, told us our boiler needed to be replaced, charged us $500 and nothing changed.

I'm a DIY kind of guy, so I took matters into my own hands. If these guys figured out how to build the system 90 years ago, I can figure out how to fix it! I read online about replacing steam traps, so I rebuilt a few...which kind of helped. I played with the water level that also seemed to help, but this year I decided to get serious.

I bought a copy of The Lost Art and read it cover to cover...twice. I learned that not only did I have a 2-pipe steam system, but also that it was a Hoffman system with a differential loop. I bit the bullet and rebuilt ALL of the steam traps, including the ones at the end of the mains. Many trap guts I pulled out looked original. That seemed to help, but after a few days the water hammer came back. I found that by letting some water out of the boiler, it would make the water hammer stay away for a 24-36 hours.

The vent on my differential loop was a Gorton #1...which doesn't have enough venting capacity for a Hoffman system (as I read in Lost Art), so I replaced it with a Gorton #2. Sweet silence...except for an odd sound...

A few of the radiators are making a water draining sound. It's not loud, but if you listen for it you can hear it. Starts mid-cycle and continues until the boiler shuts off. AS SOON as the boiler shuts off, the sound goes away. I can also hear some pipes in the walls make a cyclical glugging sound (once every 5 seconds or so) toward the end of the cycle, which also goes away as soon as the boiler turns off.

As long as the water hammer stays away, I don't care. But I want to make sure there isn't something I'm missing that's causing the sound which might lead to damage? Maybe my pipes are just old and clogged up? It's odd to me that the sound stops with the boiler turning off. Almost like it's running too much pressure?

The only thing I haven't done yet is upgrade from the pressuretrol to a vaporstat. The PSI gauge on the boiler doesn't seem to work anymore either. I've got it on the list to change the gauge to something that reads oz instead of PSI...but I'm wondering if there's something else I'm missing?

I will say, this has been a very fun journey. I'm fascinated by steam heat.

Comments

  • FredFred Posts: 7,874Member
    You need to put a 0 - 3 PSI gauge on the system to really see what pressure you are running. Your system should run on very low pressure, less then 12 ounces. You probably ought to add a Vaporstat on the system. Keep the Pressuretrol on as well because it is required by code but a Vaporstat will let you dial the Pressure down to ounces.
    Make sure all of your radiators have a slight pitch towards the return end of the radiator and that all of your Mains are pitched towards the dry return and Radiator run-outs are pitched back towards the mains. If you have any hammer or gurgling that seems to come from under the floor, raise both ends of the radiator a half inch or so and then re-pitch the radiator. That will give you some pitch on any horizontal pipes under the floor. Also make sure none of the mains or run-outs have any sags in the pipe. If so, add supports and try to take the sag out of the pipes. Anywhere water/condensate can lay in a pipe is a potential source for hammer.
    How high is the water level in the boiler? 1/2 to 2/3's is all you want.
    How old is the boiler? If relatively new or any new piping, the boiler may need a good skim to remove any oils from the surface of the water. Does the water in the sight glass bounce more than about 3/4 inch or have water droplets in the upper portion of the glass? If so, that's a good indication that a skim is needed.
  • Jamie HallJamie Hall Posts: 10,548Member

    ......The only thing I haven't done yet is upgrade from the pressuretrol to a vaporstat. The PSI gauge on the boiler doesn't seem to work anymore either. I've got it on the list to change the gauge to something that reads oz instead of PSI...but I'm wondering if there's something else I'm missing?...

    The Hoffman Differential Loop is the key to the Hoffman Equipped system. It is probably also the key to your gurgles. If the pressure at the boiler in your system goes over about 8 ounces, the differential loop will trip. This puts full boiler pressure on the dry returns (it's supposed to do that). Among other things, this will prevent condensate (which may still form) from draining freely through the traps. When the system pressure reduces, the Loop will reset, the Gorton will open, the pressure in the dry returns will return to atmospheric -- and the trapped condensate will drain. Gurgle gurgle...

    Solution to the problem: the vapourstat. I'd get a good low pressure gauge to go with it, as the modern ones aren't always as accurate as they might be. Try setting it at a 7 ounce cutoff first. While you observe the system, the boiler should cut off before the Loop trips, which you can tell (it makes a noise, and the dry return and vent will get hot). If it doesn't, crank it down a bit and try again. If the boiler shuts off properly, you're done.

    Incidentally, the Loop also protects the whole system -- particularly the traps -- from excess pressure differential, and it is likely that the traps will last forever...
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • jumperjumper Posts: 1,339Member
    Getting pressure down to ounces is big thing for your set up.
  • acwagneracwagner Posts: 131Member
    edited December 2017
    I'd recommend getting the new gauge ASAP so you can see what pressure you're actually operating at. Pressuretrols are notorious for not being calibrated accurately, so it's not a good indication at this point.

    My guess is that the pressure is going over 2psi, which is causing water to back up from boiler into the dry returns--the "A" dimension as shown in Dan's book.

    I'm in the metro-Detroit area, too, so I know the challenge of getting good steam guys.

    Edit: a few people beat me to too it. Follow their advice.
    Burnham IN5PVNI Boiler, Single Pipe with 330 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • mikeg2015mikeg2015 Posts: 806Member
    Here's a gauge I picked up. there's also I think a 32" version that might work well too.

    https://www.amazon.com/gp/product/B0087V08VA/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1

    I'm curious why you are building pressure to start with. Wonder if the boiler is a little big.
  • JUGHNEJUGHNE Posts: 5,725Member
    Do you have an auto fill valve on the boiler? It may be adding water if the return is slow for whatever reason.
    You mentioned having to drain water out sometimes.

    If you are sure your LWCO is working as intended (fire off when low water), you could shut off the water feed to check the time off for water return etc.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    Fred said:

    You need to put a 0 - 3 PSI gauge on the system to really see what pressure you are running. Your system should run on very low pressure, less then 12 ounces. You probably ought to add a Vaporstat on the system. Keep the Pressuretrol on as well because it is required by code but a Vaporstat will let you dial the Pressure down to ounces.
    Make sure all of your radiators have a slight pitch towards the return end of the radiator and that all of your Mains are pitched towards the dry return and Radiator run-outs are pitched back towards the mains. If you have any hammer or gurgling that seems to come from under the floor, raise both ends of the radiator a half inch or so and then re-pitch the radiator. That will give you some pitch on any horizontal pipes under the floor. Also make sure none of the mains or run-outs have any sags in the pipe. If so, add supports and try to take the sag out of the pipes. Anywhere water/condensate can lay in a pipe is a potential source for hammer.
    How high is the water level in the boiler? 1/2 to 2/3's is all you want.
    How old is the boiler? If relatively new or any new piping, the boiler may need a good skim to remove any oils from the surface of the water. Does the water in the sight glass bounce more than about 3/4 inch or have water droplets in the upper portion of the glass? If so, that's a good indication that a skim is needed.

    Thanks so much for this. Fantastic information. To install both a vaporstate and keep my pressuretrol, can I just T off the pigtail? Or is there more I need to do?

    Excellent info re: the radiator pitches. I'll play with it a bit. I notice no sagging in the mains or returns...but I need to check pitches.

    Boiler is quite old...probably from the 60's? Water usually bounces about half an inch, nothing crazy...and there's no water droplets in the upper portion. Only problem is the sight glass turns brown fast.

    The boiler is happiest with the water level just over 2/3. Between 1/2 and 2/3 is where it spends most of it's time, but if it drops below 1/2, it'll be more likely to hammer for some reason.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    acwagner said:

    I'd recommend getting the new gauge ASAP so you can see what pressure you're actually operating at. Pressuretrols are notorious for not being calibrated accurately, so it's not a good indication at this point.

    My guess is that the pressure is going over 2psi, which is causing water to back up from boiler into the dry returns--the "A" dimension as shown in Dan's book.

    I'm in the metro-Detroit area, too, so I know the challenge of getting good steam guys.

    Edit: a few people beat me to too it. Follow their advice.

    I'm surprised with how many old homes that have steam heat around here, there's no good steam guys I can find. I've been through 3...and I know more than they do at this point. If I ever lose my job, I'm getting certified in HVAC and getting into steam heat repair. I'd make a killing.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    JUGHNE said:

    Do you have an auto fill valve on the boiler? It may be adding water if the return is slow for whatever reason.
    You mentioned having to drain water out sometimes.

    If you are sure your LWCO is working as intended (fire off when low water), you could shut off the water feed to check the time off for water return etc.

    The auto fill is a problem child. It'll just randomly add water and over-fill the boiler. I replaced the low water cut off last year and disconnected the water fill. I check the water level daily.

    The reason I let out water is that when I do, it'll eliminate water hammer. I learned this last year when I was dealing with bad hammer. I went downstairs and noticed the boiler over-filled...so I shut it off and waited a bit for it to cool and I let water out to bring the level to 2/3. The water hammer was gone. 24 to 36 hours later, the hammer returned...I repeated the process (thought the boiler wasn't over-filled), and again the water hammer left for 24 to 36 hours. Letting just a bit of water out alleviates the hammer. Which is why I suspected something like pressure build-up or more than likely there's something wrong with the near-boiler piping that's letting the return back up into the mains?

    Before I start replacing pipes...I want to get all the other boxes checked. Rebuilt traps, proper size vent, and now a vaporstat.
  • Jamie HallJamie Hall Posts: 10,548Member
    Whatever else you do, look up Hoffman Differential Loop in The Lost Art and figure out how it works and why, and then keep it. The near boiler piping related to it is very important, as is the necessity to have one, and only one, main vent location, and that on the dry returns where they tie together above the Loop. Do not put main or other types of vents anywhere else on the system. Make sure all the dry returns come back to that point and tie there.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • DetroitSteamerDetroitSteamer Posts: 19Member

    Whatever else you do, look up Hoffman Differential Loop in The Lost Art and figure out how it works and why, and then keep it. The near boiler piping related to it is very important, as is the necessity to have one, and only one, main vent location, and that on the dry returns where they tie together above the Loop. Do not put main or other types of vents anywhere else on the system. Make sure all the dry returns come back to that point and tie there.

    I actually discovered what the loop was when I was reading the book (I had no clue what it was before that)! After reading the book and doing research, I've really come to appreciate that cluster of pipes. Everything is still setup the way it should be (only one main vent, it's actually on the loop right where the dry return connects to it I just replaced it with a Gorton #2).

    I just don't know if the rest of the near boiler piping is original. I doubt it, but hopefully it's correct for the loop.
  • acwagneracwagner Posts: 131Member
    I don't understand it, either. Detroit and suburbs were booming during the same time steam heat was king, so there are a lot of steam systems around. Many systems are being torn out because no one can find qualified people to work on them, and homeowners are getting poor advice regarding the efficiency and reliability of steam. It's a shame.

    When I redid my boiler I had to settle for finding a company that had good workmanship and had passing steam knowledge, and gave them very specific instructions on piping. In retrospect I should have just done a time and materials contract with them and taken the entire time off from work to supervise. Better for both parties. They ended up doing a bunch of rework because they didn't follow my instructions and I couldn't be there 100% of the time to supervise them due to my day job.
    Burnham IN5PVNI Boiler, Single Pipe with 330 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • FredFred Posts: 7,874Member
    @DetroitSteamer , When you add the Vaporstat, it needs to be wired in series with the Pressuretrol, not pigtailed into it.
  • Jamie HallJamie Hall Posts: 10,548Member

    Whatever else you do, look up Hoffman Differential Loop in The Lost Art and figure out how it works and why, and then keep it. The near boiler piping related to it is very important, as is the necessity to have one, and only one, main vent location, and that on the dry returns where they tie together above the Loop. Do not put main or other types of vents anywhere else on the system. Make sure all the dry returns come back to that point and tie there.

    I actually discovered what the loop was when I was reading the book (I had no clue what it was before that)! After reading the book and doing research, I've really come to appreciate that cluster of pipes. Everything is still setup the way it should be (only one main vent, it's actually on the loop right where the dry return connects to it I just replaced it with a Gorton #2).

    I just don't know if the rest of the near boiler piping is original. I doubt it, but hopefully it's correct for the loop.
    Bravo! A lot of folks -- even some good steam guys -- just panic when they see one. The more you used to it and see how it operates, the better you will like it. That Gorton #2 should be just fine -- it's all there is on Cedric in the main place I care for, and it does exactly what it's supposed to do. The vapourstat and low pressure gauge and you'll be fine.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • MilanDMilanD Posts: 1,107Member
    I read all the post quickly - re your water level rising. Not sure if you said you shut off the auto feed. That's probably a good thing in this case, as long as you check the water level daily to make sure you are not losing water without make-up being introduced.

    From what you said, the fact you have more water in the boiler after a few days points to a bad auto-feeder. It's either seeping water into the boiler (went bad), or somehow water is returning slowly and triggers the auto-fill function which could be the case with high op pressure and the differential look opening and letting the steam go into the dry returns to balance out the pressure but at the same time keeping the traps closed and water in the rads.

    As Jamie said, get vaporstat and a low pressure gauge on asap and your problems will be solved.

    Last note: I too cannot believe there are so few good steam people around the country. It's a shame, really.
  • FredFred Posts: 7,874Member
    edited December 2017
    @DetroitSteamer said: The boiler is happiest with the water level just over 2/3. Between 1/2 and 2/3 is where it spends most of it's time, but if it drops below 1/2, it'll be more likely to hammer for some reason.
    Do you happen to have a wet return or is your Hartford loop above the water line when the boiler is only 1/2 full?
    Also, as it relates to the over-filling issue, does it still do that with the Auto-fill turned off/removed? Do you happen to have a hot water coil installed in the boiler to supply the house with hot water? If so, that coil may have a pinhole leak in it, allowing water into the boiler.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    edited December 2017
    Fred said:

    @DetroitSteamer said: The boiler is happiest with the water level just over 2/3. Between 1/2 and 2/3 is where it spends most of it's time, but if it drops below 1/2, it'll be more likely to hammer for some reason.
    Do you happen to have a wet return or is your Hartford loop above the water line when the boiler is only 1/2 full?
    Also, as it relates to the over-filling issue, does it still do that with the Auto-fill turned off/removed? Do you happen to have a hot water coil installed in the boiler to supply the house with hot water? If so, that coil may have a pinhole leak in it, allowing water into the boiler.

    The over-fill was 100% the fault of the auto fill. For some reason, it'll just randomly add water in short bursts. You can hear it cycle on...maybe 5 seconds or so randomly. I've had no water level issues with the auto fill off. In fact, the water level barely changes...it goes through next to none.

    The thing I'm working to figure out now (I was just poking around downstairs) is the dry vs wet return. I do have a sizable wet return that runs around 60% of the basement...there's a main junction opposite of the boiler where the dry return drops into the wet, and that's the only time anything goes into it other than at the boiler. I was checking the pitch of the dry return and realized it could either be pitched toward the boiler or toward the wet return. No idea which is correct. Maybe I just want to make sure none of the pipes are sagging and that the dry is at least pitched in one direction or another.

    I am concerned that the wet return is all crudded up and ready for replacement. It might not be draining at full capacity, causing some backup into the dry return...and at worst into the traps to the main. Replacing the wet returns would not be fun.
  • Jamie HallJamie Hall Posts: 10,548Member
    The dry return can pitch either way -- so long as it pitches so that condensate can drain to the wet return or the boiler. But it should pitch continuously -- no sags! My bet is that it was at least meant to pitch away from the Loop connection.

    The wet return may well have sludge in it. Older ones usually do. However, if your water level is holding steady from firing to firing, as you say, it probably isn't leaking. To the current point, if the water level doesn't drop that far -- and recovers fairly quickly -- it probably isn't clogged enough to be backing up much water. Does it have, by any remote chance, Ts with plugs you can open? Or even perhaps a union somewhere along it? If so, you may be able to flush it out without too much trouble.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • DetroitSteamerDetroitSteamer Posts: 19Member
    edited December 2017

    The dry return can pitch either way -- so long as it pitches so that condensate can drain to the wet return or the boiler. But it should pitch continuously -- no sags! My bet is that it was at least meant to pitch away from the Loop connection.

    The wet return may well have sludge in it. Older ones usually do. However, if your water level is holding steady from firing to firing, as you say, it probably isn't leaking. To the current point, if the water level doesn't drop that far -- and recovers fairly quickly -- it probably isn't clogged enough to be backing up much water. Does it have, by any remote chance, Ts with plugs you can open? Or even perhaps a union somewhere along it? If so, you may be able to flush it out without too much trouble.

    The water level does seem to hold steady...doesn't loose much while it's running and returns rather quickly.

    I haven't checked for any Ts or plugs. Might worth doing.

    One tactic I've taken is draining the boiler of "mud" almost daily in hopes of cleaning it and the returns out a bit. When I first drained the boiler last summer, I was amazed at how much muddy water came out. I filled this fall, and I found that after the boiler had cycled off for 30 minutes or so, if I cracked open the drain, a bunch of muddy water would come out. Over time, the amount of muddy water that comes out is less and less. I did it today and it was all just clear water. Might be a waste of time and water, but it makes me feel a bit better in my mind. Seems like getting rid of that junk has got to be helping something.

    And that is the only thing causing the water level to drop at all.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    edited December 2017
    I did just find that the dry return was sagging at a 90-degree turn under the radiator making the gurgling sound. There happened to be a hanger right there...so I propped it up to see if that might help a bit. Here's hoping.
  • FredFred Posts: 7,874Member

    I did just find that the dry return was sagging at a 90-degree turn under the radiator making the gurgling sound. There happened to be a hanger right there...so I propped it up to see if that might help a bit. Here's hoping.

    Let's hope! Every correction is a future problem already resolved.
  • DetroitSteamerDetroitSteamer Posts: 19Member
    Fred said:

    I did just find that the dry return was sagging at a 90-degree turn under the radiator making the gurgling sound. There happened to be a hanger right there...so I propped it up to see if that might help a bit. Here's hoping.

    Let's hope! Every correction is a future problem already resolved.
    Didn't fix it. But agreed...one less thing to fix in the future!
  • FredFred Posts: 7,874Member
    Probably won't resolve the gurgling sound until you get the Vaporstat on the boiler and lower the pressure down to ounces. Just can't get low enough with a Pressuretrol. Here is the Model Vaporstat you want: https://www.supplyhouse.com/Honeywell-L408J1009-Vaporstat-Controller-Steam-0-to-16-oz-in2
  • jumperjumper Posts: 1,339Member


    I'm surprised with how many old homes that have steam heat around here, there's no good steam guys I can find. I've been through 3...and I know more than they do at this point. If I ever lose my job, I'm getting certified in HVAC and getting into steam heat repair. I'd make a killing.

    I am not surprised. So many steam heat houses do well for years without any service. And what service is required requires only a boiler guy.

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