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Drop headers

PatNH
PatNH Member Posts: 4
Will a drop head add any value to a single outlet boiler? Have low head room and need the drop to add piping above water line.
Mad Dog_2

Comments

  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    My opinion: yes, just as much value as it will add to a dual-outlet
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    PatNH
  • Tim McElwain
    Tim McElwain Member Posts: 4,612
    It will also help prevent wet steam and water hammer created because the new steam boilers produce steam much faster and at higher velocity leaving the boiler.
    PatNH
  • Jamie Hall
    Jamie Hall Member Posts: 23,161
    Drop headers are useful for two risers, yes, as they alost inevitably give you two swing joints to take the stress off the boiler. They are also handy in low headroom situations. But -- the real reason to use them is the one @Tim McElwain mentioned: much better quality steam.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    PatNH
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    Yes, we use them on just about every installation. They produce better steam and allow some wiggle room when hooking up the boiler. Even on a single riser installation they may reduce stress on the boiler since the whole piping system is moving as the system heats up and cools down.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    Neild5PatNH
  • PatNH
    PatNH Member Posts: 4
    Thanks guys,  I will be doing this job this morning,  I will send some pics. 
  • JohnNY
    JohnNY Member Posts: 3,226
    Just to play devil's advocate here....I'd like someone to show me the difference in the moisture content of a small residential boiler's main distribution pipes piped with a drop header versus a standard header.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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    Precaud
  • The devil probably knows a few things about heating, given the purpose of his domain. Population increases, along with a rise of bad behavior must make the expansion of his system a constant activity!
    I wonder how that could be measured—maybe with a viewing port of Pyrex glass set into a tee in the drop header, or a conventional header.
    The advantage of the drop header is in its capacity to give more mechanical isolation for differences of thermal expansion and contraction between the boiler block, and the header itself, (particularly in the case of welded headers). More wiggle room for fitting the pipes together would be another plus.—NBC
  • JohnNY
    JohnNY Member Posts: 3,226
    edited November 2020
    Thermal expansion on a single-riser boiler is a non issue. There’s no way to test for wet steam in the field that I know of and that kind of makes many of the performance benefits of a drop header theoretical.   
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    I disagree. Thermal expansion is still an issue on a single rider boiler for 2 reasons.... The header drip can still be fixed to the boiler ( Even Weil shows a minimum piping arrangement with threaded joints on the return) and the system piping also tends to move, causing stress on the boiler.
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    ethicalpaul
  • AMservices
    AMservices Member Posts: 610
    Water hammer is a clear sign of wet steam.
    Calculating steam exit velocity is another way we can find if there's carry over.
    We can't always see what's happening inside of pipes. So we have to rely on numbers and our senses.
    A drop header or a over sized header is doing the same thing a steam/liquid separator would do. It gives a larger area for steam to slow down before entering the mains, and if there's any carry over of water to collect then drain back into the boiler.
    Having more swing joints with a drop header makes it easier to work with when connecting big pipe.
  • Ironman
    Ironman Member Posts: 7,367
    You can see what's going on in the header. Remember W/M's demo boiler with the glass header?

    Someone should be able to post the video of it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,452
    @ethicalpaul
    Has glass tubing on his boiler
    I think the drop header thing can be over done. I have never had a problem piping to the MFG spec along with boiling out with TSP and skimming.

    If I am not mistaken @ethicalpaul piped his boiler with two risers and only 1 was required. With valves on the risers he shut 1 off and had no carryover.

    I am sure someone will correct me if I am wrong
    ethicalpaul
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    Eberatt. I largely concur....I use the drop header mainly for ease of piping and reduced stress on the castings, though I am sure it helps when boilers start getting fouled. Now If I am piping into a vacuum system, I would definitely go well beyond the manufacturer's piping. Using 2x 3 inch risers on a little 200,000 btu boiler is a bit much. I'd rather put that extra money into better venting and other system improvements ( water meter, etc). If its a side tapped utica/dunkirk I go a little more beyond the minimums.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    @ethicalpaul Has glass tubing on his boiler I think the drop header thing can be over done. I have never had a problem piping to the MFG spec along with boiling out with TSP and skimming. If I am not mistaken @ethicalpaul piped his boiler with two risers and only 1 was required. With valves on the risers he shut 1 off and had no carryover. I am sure someone will correct me if I am wrong
    You are right Ed. What I learned for my 63-03L was that the normal recommended piping was fine if the water quality is ok. Neither the drop header nor the second tapping is necessary for my boiler.

    Any of these is what I found can push water past the header into my main riser:

    - too high water level, like above the top of sight glass
    - too much water treatment / too high ph (this one is very easy to experience)
    - Oil, etc

    Other boilers with more steam flow may benefit from extra capacity, refer to those excellent PDFs that show the steam rates for every model

    here’s one of my videos showing it in action: https://youtu.be/4IymyZB4wlI

    here’s carryover from bad water: 

    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    kcoppStuckWithSteam
  • JohnNY
    JohnNY Member Posts: 3,226

    Water hammer is a clear sign of wet steam.
    Calculating steam exit velocity is another way we can find if there's carry over.
    We can't always see what's happening inside of pipes. So we have to rely on numbers and our senses.
    A drop header or a over sized header is doing the same thing a steam/liquid separator would do. It gives a larger area for steam to slow down before entering the mains, and if there's any carry over of water to collect then drain back into the boiler.
    Having more swing joints with a drop header makes it easier to work with when connecting big pipe.

    I agree that having more swing joints kind of helps a little, but the rest is, again, theoretical. And by your logic, the absence of water hammer is what? A clear sign of dry steam? @ethicalpaul 's video is pretty clear evidence to me that second boiler take-offs and drop headers are a frivolous expense on many smaller residential boilers.

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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    ethicalpaul
  • AMservices
    AMservices Member Posts: 610
    @JohnNY is steam velocity theoretical?
    Im not saying a drop header is always necessary but for some boilers im sure it helps.
  • JohnNY
    JohnNY Member Posts: 3,226

    @JohnNY is steam velocity theoretical?
    Im not saying a drop header is always necessary but for some boilers im sure it helps.

    I'm sure you're right too. I'm just saying I'd like some evidence showing that at some point steam velocity is guaranteed to carry water out of a standard header and into the system.

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • AMservices
    AMservices Member Posts: 610
    Ideally the steam velocity should be under 15 feet per second before entering the mains.
    Maximum velocity for 1 pipe riser (the point that condensate can't flow backwards)
    2"-23 fps
    2.5"-26 fps
    3"-29 fps
    4"-32 fps

    If the velocity through the riser or risers out of the boiler is greater then those values, then using a drop header is necessary.

    Page 73. LAOSHR
    "The risers out of the boiler should be from 30 to 50% greater in area then the mains, which they feed"
  • JohnNY
    JohnNY Member Posts: 3,226
    @AMservices Isn't that great info? Thanks for posting.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,951
    Maybe glass/see through piping should be mandatory. 
  • JohnNY
    JohnNY Member Posts: 3,226

    Maybe glass/see through piping should be mandatory. 

    Well, it's really an eye opener at least. Again, I'm just not convinced of the necessity of overdoing a header. At some point, the cost to consumer isn't justified by the performance.

    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    I don't know about mandatory...I'd rather see the manufacturer's minimum be mandatory per code first :lol:

    But if I were an installer, I'd definitely sell a premium option of a sight glass on the riser. As I've said before, it's not even much of an extra expense. The ones in my video are $80 and you get a free union thanks to the tri-clamp.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    AMservicesJohnNYPrecaud
  • Jamie Hall
    Jamie Hall Member Posts: 23,161
    I don't think the question should be "are drop headers beneficial". There are two very different considerations here, and for any given application it is going to be a cost/benefit question.

    Drop headers can be useful in two ways.

    First, they make it much easier to create means -- usually swing joints -- to reduce stress on the boiler -- either from the differential expansion of the boiler itself, or from shifting between the boiler and the rest of the system piping. Are they required for this? No. Is some means of reducing stress required? Yes. Are a lot of systems out there piped without such obvious means? Yes -- but one will find looking around the system that the expansion is being allowed somewhere.

    Second, they help in reducing carryover into the system (which is not the only, nor even the most common, cause of water hammer out in the system, by the way). Here again, they aren't really necessary, but they help. In the header, a lot of the effect on water carryover comes from two factors: sheer size, and the way the risers and takeoffs are connected. If the risers and takeoffs are connected on the top, even a small header will work well. Risers on the side, not so well. A single riser at one end on the bottom is fine; two connected on the bottom -- not good, unless the header is very large. Size also matters -- a really big header, approaching the size of the old steam drums, is not likely to be a problem (there's a reason for steam drums on power boilers, especially for turbines!).

    So is a drop header required for all installations? No. The installer needs to weigh the advantages and disadvantages and select the best solution -- on a cost/benefit scale -- for the job.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    AMservicesNoelCanucker
  • hvacfreak2
    hvacfreak2 Member Posts: 500
    For modern boilers a drop header is probably essential ( but the only sight glass that would matter is the riser (s) to the system imo ). Insulation of the header ( straight or drop ) is a better bang for the buck in my travels.
    hvacfreak

    Mechanical Enthusiast

    Burnham MST 396 , 60 oz gauge , Tigerloop , Firomatic Check Valve , Mcdonnell Miller 67 lwco , Danfoss RA2k TRV's

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  • Neild5
    Neild5 Member Posts: 166
    Maybe glass/see through piping should be mandatory. 
    I am not sure I would want to know what glass pipe would cost on the 5" riser on my system.
  • STEAM DOCTOR
    STEAM DOCTOR Member Posts: 1,951
    5" pipe and related work is quite expensive. Probably would not notice the difference. But I could be wrong. 
    ethicalpaul
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,452
    It boils down to riser velocity but that isn't all. Two different boilers with the same capacity will act differently.

    But generally keeping the velocity down keeps water in the boiler
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    Neild5 said:
    Maybe glass/see through piping should be mandatory. 
    I am not sure I would want to know what glass pipe would cost on the 5" riser on my system.
    The largest I could find was 4”, suitable for a 3-1/2” npt pipe.

    How many sq ft of steam is your system?!
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Neild5
    Neild5 Member Posts: 166
    Neild5 said:
    Maybe glass/see through piping should be mandatory. 
    I am not sure I would want to know what glass pipe would cost on the 5" riser on my system.
    The largest I could find was 4”, suitable for a 3-1/2” npt pipe.

    How many sq ft of steam is your system?!
    There is 2565 sqft of EDR. It's a 20 unit apartment building from 1927 that went condo in the 90's.   
    ethicalpaul
  • JohnNY
    JohnNY Member Posts: 3,226
    Neild5 said:




    Neild5 said:



    Maybe glass/see through piping should be mandatory. 

    I am not sure I would want to know what glass pipe would cost on the 5" riser on my system.

    The largest I could find was 4”, suitable for a 3-1/2” npt pipe.

    How many sq ft of steam is your system?!

    There is 2565 sqft of EDR. It's a 20 unit apartment building from 1927 that went condo in the 90's.   

    A single 5" outlet supplying 2,565 sq. ft. EDR? Is this a Scotch-Marine-type boiler or maybe an atmospheric boiler like a Weil-McLain LGB-9 or similar?
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • Neild5
    Neild5 Member Posts: 166
    It is a Peerless TC-II 4 section boiler.  It was just installed by Dave @The Steam Whisperer.
    heathead
  • JohnNY
    JohnNY Member Posts: 3,226
    Beautiful job. Wow.
    Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
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  • JUGHNE
    JUGHNE Member Posts: 11,042
    Great looking job....some serious piping there.
    Is that a pressure transducer installed? Hi/low fire?
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,215
    It's a full mod burner. We installed it in anticipation that
    TRV's may be installed on the one pipe system.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    JUGHNENeild5
  • Neild5
    Neild5 Member Posts: 166
    Once it gets up to pressure, the pressure gauge needle looks like it is stuck, it does not move but the burner controller will drop to 40 to 60% fire and varies every second until the thermostat is satisfied. 
  • Onepipe
    Onepipe Member Posts: 47
    Quick question for drop header design. I have installed a few but I have always had headroom on this particular boiler that I am working on I have low headroom for the main tie in. Is it OK to drop the header below the 24" above the water line? I always like to say at min 24" above the top of the boiler but I would need to drop down to about 12-16" above the boiler before I tie into the supply line. Is that OK to do or am I asking for hammer? Its a two pipe header and im a huge fan of swing joints. Also I always try to have some pitch on my headers towards the equalizer leg but I am seeing a lot of drop headers that have no pitch. Is it OK to run the header level?
  • Jamie Hall
    Jamie Hall Member Posts: 23,161
    Yes it is Ok. You still need to go up the 24 inches or so for the initial rise, but then you can ben over and drop as low as you like so long as you stay above the top of the boiler. I'd still run the header with pitch, though.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,452
    @Onepipe as @Jamie Hall said yes you can drop the header. The bottom of the header must be above the water line under any condition the boiler runs at. I would keep the bottom of the header at least at the height of the top of the boiler. Higher is better.