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    Flushing a Weil McLain Steam Heat Boiler (21 Posts)

  • Ritzy Ritzy @ 7:28 AM
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    Flushing a Weil McLain Steam Heat Boiler

              During the winter months, my steam heat boiler (Weil McClain) makes very loud banging noises.   I know next-to-nothing about boilers (except to take a bucket of water off of them once every few weeks during the heating season).
             Is it safe to have this boiler flushed during the summer...not during the heating season?
             Does "flushing" the boiler hurt the system in any way? 
             Will I expect after-effects of the flushing during the heating season? 
             I understand that flushing the system involves putting something into the radiators that travels through the system.  Does this cause smells in the evaporating steam from the boilers during the heating system?  I have asthmatics in the house.  Any responses are greatly appreciated!
  • nicholas bonham-carter nicholas bonham-carter @ 8:45 AM
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    "flushing" a steam boiler

    when you "flush" the boiler, what part are you taking the bucket of water from?
    on the boiler, there is the low-water cut-off [lwco], some models of which which have a float-chamber which must be drained out to clear any sediment which would interfere with the float. this device will detect a low-water condition and prevent the burner from firing, or can also turn the automatic water feeder.
    there is also a bottom boiler drain, which can be opened yearly to drain out loose particles of rust, and calcium.  this should be left to the experienced technician.
    as i do not believe in the addition of chemicals to the boiler water, i cannot comment on the possibility of smells resulting from this. my boiler works fine without anything other than water.
    how old is your boiler?
    there are some books for sale here which would bring you up to speed on steam heating, and teach you how to maintain your boiler, and enable you to understand the technician.
    http://www.heatinghelp.com/products/Steam-Heating-Books/25/129/A-Steamy-Deal
    some pictures of your boiler would show us where the "flushing" has been performed.--nbc
  • Rod Rod @ 11:19 AM
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    Need More Pictures

    Hi- As NBC mentioned you need to get the steam books. They're written so the homeowner can understand them and are easy, humorous reading. They are packed full of facts, pictures and explanations of how residential steam systems work and in an evening or two of reading will put you knowledge of your steam system light years ahead. I would start will "We Got Steam Heat!"  as it is a good introduction.
    http://www.heatinghelp.com/products/Steam-Heating-Books/25/61/We-Got-Steam-Heat-A-Homeowners-Guide-to-Peaceful-Coexistence
    This book is part of the package NBC mentioned in his post above. 

    Please post some more pictures of your boiler and the piping connected to it. The more we learn about you system the better we'll be able to help you. Take the pictures from all angles and "farther back" so we can trace  the  piping. The pictures don't have to be " up close" as we can blow them up if we need to see detail.  You might also include a picture of one of you radiators so we can determine what type of steam system you have.

    Do you have main vents?  Where are they located? Perhaps a picture of them may help us.

    While you may need a flushing, generally you want to do that with plain water with NO additives. I might also mention that it is very important to heat any "new" water to the boil after it has been added to the boiler as this drives off dissolved oxygen which can be very corrosive and shorten your boiler's life span.
    Steam systems shouldn't bang. When does the "banging" occur? When the boiler is first started or later during the heating cycle?
    Tell us more about your system and we'll be able to help you.
    - rod
  • Ritzy Ritzy @ 12:21 PM
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    Boiler Pipes

    First of all...thank you to NBC & Rod!   I am posting more pictures with this note (thread),  The first picture shows the glass pipe area from which I take a bucket of water regularly that is slightly rusty each time during the heating season.
    The other pictures show the pipes that rise up to the ceiling and go across... with 2 silver vents in them.
    Also, the downstairs in my house has 3 in-wall radiators (I know this is bad for getting heat).  The upstairs has 3 external radiators, as one is pictured.  I tried to elevate these upstairs radiators on one side in order to minimize the gas boiler's loud banging.  I should note that the loud banging sounds emanate from the boiler...not from the radiators.  I greatly appreciate whatever suggestions you can give me to minimize the gas boiler's banging and about possibly flushing the system, if necessary.  Thank you, again!
  • Rod Rod @ 1:22 PM
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    System Pictures

    Hi- Thanks for posting the pictures. They are very helpful.  Could you take more of the boiler from farther away so we can trace out the piping?  As I mentioned we can blow them up if we need to look at detail.
    You mentioned that you are draining off water bucket of water regularly during the heating system, Why are you doing this?
    When the boiler is operating at what pressure does it shut off? 
    I've attached one of your pictures with labeling. Where does the pipe in the direction marked "A" go?   Direction marked "B" ?
    Are there any markings/numbers on your main vent that could help us identify it? I don't readily recognize this type of main vent but If I had to guess I would say this is a Dole #4.
    - Rod
    This post was edited by an admin on July 30, 2011 1:38 PM.
  • nicholas bonham-carter nicholas bonham-carter @ 1:28 PM
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    glass pipe area

    i am not sure that you have a float type low water cut-off,  and if that is the case, there is no need to drain off the water. more pictures would be useful.
    the water in the boiler may have never been properly cleaned of oily surface residue [skimming], and this may be the cause of the banging [water-hammer]. unfortunately, as the oil is on the surface, it can only be removed from the surface by skimming. which could be done by you with some instructions from us.
    your boiler should be capable of silence, and the original installer of the system long ago would have lost business once it became known that his systems could be heard at all!
    i do notice that your silver main vents, which do all the work of letting air out as steam is rising; are to small and inadequate. this forces your fuel supplier to squeeeeeze the air out of their constipated little openings, with detriment to system efficiency and your wallet.
    as rod has said, the pictures of the supply piping, and of the "honeywell pressuretrol" will enable us to diagnose the water-hammer problem. include the model number as well so we can see where the skimming port might be.--nbc
  • Ritzy Ritzy @ 6:38 AM
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    Flushing a Weil McLain Steam Heat Gas Boiler

    The model # of my Weil McClain gas boiler is EG45 and it was installed in 2001.  Also, I have posted more pictures of the Honeywell pressuretrol and rising steam pipes that cross the basement ceiling in different directions to go to the 1st floor of the house.  Thank you.
  • Rod Rod @ 4:06 PM
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    Boiler Piping

    Hi - I've been studying your pictures and have a few questions. In the attached picture could you take a couple of photos from different angles of the boiler piping in the drawn circle? Also need to know what the pipe labeled "G" comes from and goes to.
    - Rod
  • Ritzy Ritzy @ 6:09 PM
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    More Pictures of my boiler & heating pipes

    Hopefully, I took this pictures from appropriate angles.  Please let me know if I did not.  Thank you, again!
    This post was edited by an admin on July 30, 2011 6:11 PM.
  • Ritzy Ritzy @ 6:13 PM
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    More pictures are on the way

    My camera just broke....I'm getting another camera from my neighbor and will post more pictures this evening from more angles.
  • Ritzy Ritzy @ 7:29 PM
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    More Pictures of my boiler & heating pipes

    Here are some more pictures.
  • Ritzy Ritzy @ 6:26 AM
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    Pipe Labeled "G"

    This black pipe rises out of the boiler and goes towards the ceiling.  It then goes through a thin, wooden wall into an adjoining room (across the ceiling) as in the pictures.  This pipe, then, travels upwards towards one of the first floor radiators.
  • Rod Rod @ 5:09 PM
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    Pipe Sizes?

    Hi-
       Thanks for posting the latest pictures. It would appear that you have two steam mains going from your boiler.  In the first picture labeled “End of Main” is this at the end of Main #A” or Main “B” ? (See picture labeled “Boiler Piping”)
    The other steam main should have the same configuration with its own Main Vent and a Dry Return.  Can you give us a picture of the end of this steam main?

    Returns- The Dry Returns at the end of each steam main should drop down to floor level and lead back to the boiler and connect to the Wet Return (see “WR” in the Boiler Piping Picture) If you can take a picture of this connection it would be great!

    Boiler Piping Picture- As you can see from the table from the installation manual the Boiler Riser (“X”) and the Header (“Y”) should be the same size (2 ½ inch pipe). I can’t tell from the pictures if this is so . Can you measure the circumference of each pipe? (“X” and “Y” ) They should be the same.  2 ½ inch pipe has a circumference of just over 9 inches (9.0320) From the pictures, the Equalizer Pipe (“Z”) looks okay. It should be 1 ½ inch pipe with a circumference of just a touch shy of 6 inches (5.969)
    The whole purpose of the checking the pipe sizing is to make sure your installation matches the boiler manufacturer’s recommend pipe sizing. Missized /configured near boiler piping is one of the biggest sources of steam system problems.

    Boiler Picture- I’ve labeled the different components. You have a probe type Low Water Cut Off. This should be serviced/cleaned /inspected  once a year by a pro. This is a safety device which turns off the burner if the water in the boiler runs too low. The pipe mentioned earlier as “G” is the gas pipe which brings natural gas to your boiler’s burner.

    Let us know the pipe sizes of “X” and “Y” and how the returns are configured and we’ll go from there.
    Again I would suggest that you get "the steam books" as they explain all this and much more far better than I. To a homeowner with a steam system, the steam books are worth their weight in gold. They have saved me at least a hundred times their cost!
    - Rod
  • Ritzy Ritzy @ 8:39 PM
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    Flushing a Weil McLain Steam Heat Gas Boiler

    Thank you, Rod.  I will get these measurements that you mention and post them tomorrow (I need to borrow a camera still...mine has expired). I do seem to recall seeing a pipe coming up from the floor at the bottom of my basement steps; however, it is impossible to trace from where it comes under the cement...once it appears at the bottom of the steps, the pipe continues back to the boiler.  I will take a photo of this tomorrow, too.  Thank you so much for your time in helping me...I truly appreciate it.
  • Ritzy Ritzy @ 12:01 PM
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    Pictures of Pipes from Main A & Main B

    Thank you, again, Rod.

    In the first picture labeled, "End of Steam Main," this is the End
    of Main B.   Below, I am attaching a picture of the End of
    Steam Main A  that drops down to the floor and disappears under
    the floor's cement...as does the end of the down-pipe from the End of Steam
    Main B.

    I am attaching a picture, also, of the heading-back pipe to the boiler that
    connects to the Wet Return just before reaching the boiler.  There is also
    a photo of the heading-back pipe that heads towards the Wet Return as it comes
    up from the cement floor just under the basement's first step. It would appear
    that both down-pipes from the End of Mains A & B disappear under the cement
    floor...possibly meeting?...then, reappearing as the return, heading-back pipe
    to the Wet Return.

    Boiler Pipe X measured 2.75 inches across; Header Pipe Y measured 2.50 inches
    across...the circumference of both are definitely not equal...even
    visually.  Equalizer Pipe Z measured 1.75 inches across. 

    Your responses are very appreciated.  As you suggested, I will look for
    those steam books, too.  Thank you, again.
  • Ritzy Ritzy @ 12:03 PM
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    Pictures of Pipes from Main A & Main B

    Thank you, again, Rod.

    In the first picture labeled, "End of Steam Main," this is the End
    of Main B.   Below, I am attaching a picture of the End of
    Steam Main A  that drops down to the floor and disappears under
    the floor's cement...as does the end of the down-pipe from the End of Steam
    Main B.

    I am attaching a picture, also, of the heading-back pipe to the boiler that
    connects to the Wet Return just before reaching the boiler.  There is also
    a photo of the heading-back pipe that heads towards the Wet Return as it comes
    up from the cement floor just under the basement's first step. It would appear
    that both down-pipes from the End of Mains A & B disappear under the cement
    floor...possibly meeting?...then, reappearing as the return, heading-back pipe
    to the Wet Return.

    Boiler Pipe X measured 2.75 inches across; Header Pipe Y measured 2.50 inches
    across...the circumference of both are definitely not equal...even
    visually.  Equalizer Pipe Z measured 1.75 inches across. 

    Your responses are very appreciated.  As you suggested, I will look for
    those steam books, too.  Thank you, again.
  • Rod Rod @ 4:50 PM
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    Header Pipe

    Hi - Thanks for posting the pictures as we now have a better idea of how your system is laid out. It would appear that you have a standard 1 pipe parallel steam system.
    Header Pipe- I couldn’t tell for sure in the pictures but your checking of the measurements shows the header pipe is undersized. By the manufacturer’s recommendation, it should be at least equal to the riser pipe (2 ½ inch pipe) coming out of the boiler and most steam pros would suggest go a pipe size larger on the header pipe (3 inch pipe) as this makes for very dry steam.  The header pipe’s function is to help separate water droplets from the steam stream which “drys” out the steam. Going to a larger header pipe slows down the steam stream which helps the droplets precipitate out. In your system going from a large riser pipe to a smaller header pipe has the affect of like putting your thumb over the end of the garden hose. It speeds up the steam stream which doesn’t give much chance for water droplets to drop out. This results in what is known as “Wet Steam” which is very inefficient.  Wet Steam is much more likely to condense back to a liquid and this condensing (the steam “collapsing”) is what is most probably causing the “banging” .   Other contributors to steam collapse are lack of insulation on the piping and “dirty” (unskimmed ) boiler water.
    Since you have a lot of pipe unions in the near boiler piping correcting the pipe size should be a fairly easy job if you wish to have it done.  I’ve attached a header drawing which show what happens in a steam header. BTW - Did you get my email with the article on skimming attached?

    Overall your steam piping looks pretty good. The original installer obviously knew what he was doing.  Items you might want to upgrade:
    1. Main Vents- your present main vents are rather small venting capacity wise. Replacing them with larger capacity main vents would help the system.
    2. You didn’t mention at what pressure your system is now running. It shouldn’t be operating at more than 2 PSI and even lower than that is better. The 0-30 PSI gauge on the boiler is required by code though, from the stand point of telling you anything, is next to useless. More people add a 0-3 PSI gauge 
    http://www.gaugestore.com/prodinfo.asp?number=33020
    as this gives you a much better idea of how your system is running.
    3. Insulation on the steam pipes would also be a big help. Here’s a link to an article of Dan’s on insulation
    http://www.heatinghelp.com/article/325/Piping/300/Why-you-should-insulate-steam-pipes

    Returns-  It sounds as though your returns join up under the cement. While it is much more convenient to have the return piping where you won’t trip over it, there is the disadvantage that if a buried return starts to leak you won’t detect it easily. If you ever are having to suddenly add water regularly to your boiler this is a sign that the buried return is leaking.
    - Rod
    This post was edited by an admin on August 1, 2011 5:18 PM.
  • Ritzy Ritzy @ 7:53 PM
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    Thank you!

    All of your suggestions have been most helpful, Rod.   I will pursue all of your suggestions....and, get those books that you recommended.
  • Ritzy Ritzy @ 7:58 PM
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    Pressure?

    One more question, Rod: 
    You said that I didn’t mention at what pressure my system is now running.  How can I determine at what pressure my system is running?  Thanks so much!
  • Rod Rod @ 9:23 PM
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    Pressure and Pressuretrols

    Hi-
    To answer your question maybe first I need to give you a better idea of pressure and pressure control in a steam system.
    The Pressuretrol control is the gray box mounted above the pressure gauge. It controls the steam pressure in your boiler and does this by turning on and off the burner.  If you set the maximum high setting (cutoff)  at say 1 ½ PSI and the differential at 1 (PSI) that would mean the  Pressuretrol would turn off the boiler’s burner when the pressure reached 1 ½ PSI and after the pressure dropped 1 PSI (the set differential) to ½ PSI,  the Pressuretrol would turn (cut in) the burner back on the burn and the on and off cycle would repeat until the setting on your wall thermostat was reached.

     When I was asking what pressure your system was now running I was asking what the pressure reading was on the pressure gauge when Pressuretrol shuts off the burner. I used 1 ½ PSI in the example above but initially all we are interested in is that your maximum (high setting) pressure is 2 PSI or under.  (On the 0-30 PSI gauge provided this can be hard to determine accurately which is why a lot of people favor adding the 0 -3 PSI gauge). Running the system at a higher pressure than 2 PSI wastes fuel and can contribute to  problems like “banging”.

    Don’t be surprised if the pressure doesn’t rise on the gauge. When the boiler (burner) is first turned on and the radiators are cold, the steam is condensing in the radiators as fast as it is being produced by the boiler.  It is only when there is more steam available than that being condensed, does the pressure finally build up.  Also in the spring and fall, in mild temperatures, the radiators don’t even get filled with steam before enough heat has been put out to satisfy the temperature setting on the room thermostat which then shuts off the burner before steam pressure gets a chance to build.   I didn’t mention this before but both the Pressuretrol and the thermostat have the ability to shut off the burner (as does the On /Off switch mounted on the boiler  to the right of the Pressure gauge)
     Dan's steam books explain all this much better than I so they will be a big help to you.
    - Rod
  • Ritzy Ritzy @ 9:48 PM
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    Pressure

    Thanks so much, again, Rod!  Your explanations have been very clear.  I am most appreciative of the time that you have taken to examine my boiler's situation.  
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