Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Main Vents Maximised

crash2009 Member Posts: 1,484
Gerry Gill was right about everything else.  So, Why not?  According to Steve and Gerrys Venting Handbook, (at least the way I read it) a 3/4" pipe will vent about the same as four and a half Gorton #2's (G2's).  The antler on the right is pretty much done, just need one more G2 for that side.  The antler on the left, is not quite finished.  I ran out of nipples.  Need to add one more T.  I am not sure why I installed the pigtail and gauge.  Guess I was just curious what the pressure might be up there.  Five T's and the vents weighs a lot.  The first time I put them up there I lost my pitch.  The tail end filled up with water, and the last vent stopped working.  Went down to the hardware store and got a couple Street 45's, no more pitch problem.

Anybody ever thought about the effects of having two different kinds of main vents on the same antler?  I do have a few G1's laying around.  Although I would prefer to keep the Hoffmans on there.  I like that re-asurring CLINK when the steam hits them.

Some of the old vents were soaked overnight in CLR.  They were washed out real good the following day.  The CLR made the Hoffmans look like brand new again.  I have my fingers crossed that the Gortons like the same treatment.


  • Rod
    Rod Posts: 2,067
    edited November 2011
    Mixed Main Vents.

    Hi Crash- I've often wondered whether it would be a good idea to use Gortons along with a Hoffman. I remember reading somewhere (most probably something by Gerry Gill) that the Gortons, being bi - metal, closed at around 145 degrees F. The Hoffmans operate on the principle of a boiling alcohol /water mix so I would expect they would close much closer to 212 degrees F.  Solely using Gortons, (145 degree),  does this mean that there might still be air left in the mains and if so, does it have any affect of the system and would it be a benefit to include a Hoffman on the antler?  Just a thought .

    Any conclusions on the Max venting yet?

    - Rod          
  • Steamhead
    Steamhead Member Posts: 15,751
    Mixing main vents

    shouldn't be a problem. None of them close until they get warm, so the steam would be right there or pretty close. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • gerry gill
    gerry gill Member Posts: 3,047
    thats a fine looking job!

    Steam ought to move fast now..it won't hurt at all to mix vents.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • Looks great!

    Wow, that is some serious venting, it looks great! Just out of curiosity, do you have a projected ROI for that project? Those Gs are not exactly cheap.

    What kind of elbows did you use to get the desired pitch of the antlers, are those pairs of 45 degrees ones?
  • crash2009
    crash2009 Member Posts: 1,484
    When do main vents open?

    I don't know if this is a benefit or not but it seems like the Hoffmans start floating on a cushion of air/steam/mixed, at about a half ounce, the float, kinda gently, rattles (clinkity clink) around inside the case, and maybe just gets lifted into position.  Then when the boiler pressure gets up to about one and a half ounces, you can hear it get pinned to the top of the case (CLINK).  About 13 minutes after the burner has shut off, you can hear a loud (CLINK) again,  which I think is the alcohol cooling, and the float falling.  

    This is the part of the venting cycle that the Hoffmans allow the atmosphere back in to the system.  Wouldn't it make sense to keep the atmosphere out of the system as long as we can?  When do the Gortons open and allow the atmosphere back in?    
  • crash2009
    crash2009 Member Posts: 1,484
    No, I havn't done an ROI projection

     Just acting on a theory that I agree with.  Last season I ran six vents, did a lot of work the summer before, reduced the gas bill around $750.  Another four Gortons $200, might get it back this season.  The theory is, if your boiler runs for 20 minutes, and it takes 10 minutes just to get the steam to the end of the main, how much does that cost you?  Now, same boiler, steam to the end in 3 minutes, knock 7 minutes off your run time, now multiply those 7 minutes by the 20 times per day your boiler comes on.  I am just looking to save 10-15 minutes per day.  Maybe I won't get it back this year, but it will be for sure next year.

    Maximizing is not a new thing, just new to me.  http://www.gwgillplumbingandheating.com/webapp/GetPage?pid=415   here are some more facts  http://www.heatinghelp.com/products/Steam-Heating-Books/25/146/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-by-Gerry-Gill-and-Steve-Pajek  Yes, thats a pair of 45's.  These venting stations are heavy, they sag when you hang them on 3/4" nipples.   I am going to bolt them to the floor joist eventually.  and insulate.
  • Thank you

    Great info, thank you Crash. Cutting the "time to full steam" by seven minutes is indeed a significant money saver.

    I was wondering if one could use brass pipes to build complex vents, it might be a little lighter and "less space taking" solution.
  • ChrisJ
    ChrisJ Member Posts: 13,859

    Nice vents Crash.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Dave in QCA
    Dave in QCA Member Posts: 1,776
    WOW! Vents Galore!

    Crash, I suspect if you get anough vents connected, you might be able to make steam without using any gas at all!

    Don't I recall that your original conditions included a reduced firing rate because of a undersized gas line?     :)
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • crash2009
    crash2009 Member Posts: 1,484

    would look nice wouldn't it.  But then you'd have to polish it. The accountants would have a canary when they figured out the ROI :-) 
  • crash2009
    crash2009 Member Posts: 1,484
    It's about time

    that I practice what I preach huh?
  • crash2009
    crash2009 Member Posts: 1,484
    I won't forget that trick

    How to downfire a natural gas steam boiler.  I'm glad that "No Pressure" thread is dead and burried. 

    I got up to one and a half ounces this morning, after burning for 35 minutes.  Thermostat shut me down shortly after.  Have been playing with the anticipator again.  Seems like you just get it set right and bam summers here. 
  • Danny Scully
    Danny Scully Member Posts: 1,396

    You got something againts 3/4 x 1/2 blk tees? Haha, just kidding it looks great.
  • crash2009
    crash2009 Member Posts: 1,484

    All my spares are G1's.  Our plumber said I needed the practice:-)
  • AlexR
    AlexR Member Posts: 61
    venting vs condensation

    At some point, your venting rate exceeds the rate at which your boiler can heat the pipes.

    For example, my two mains contain about 87 lbs of iron which takes about 1450 btu to heat from 60 to 212.  If my boiler's output is 1400 btu/min, then it doesn't make sense to install vents that would give a venting time of less than a minute, because the steam just won't move that fast.  So there's a fun calculation you can go do for you system.  Bonus points if you post a graph of actual vs predicted venting times for us. :)

    Those are awesome pictures!  I'm jealous!

  • crash2009
    crash2009 Member Posts: 1,484
    I can't disagree

     with what you say Alex.  There must be a point where too much of a good thing becomes a bad thing.  It's too early to tell if I have reached that point.
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2011

    This is what the data logger recorded for the last two days.  NOV22A was with seven Gorton 2's and two Hoffman 75's.  NOV23A was with seven Gorton 2's and three Hoffman 75's.  I disabled six of the vents this morning (just turned them upside down) in anticipation of the weather staying the same for awhile, but a warm front blew in and the experiment is now cancelled. 

    Do you think this data logger will show a difference in fuel use if I all of a sudden cut the venting in half, while all other factors remain the same?
  • AlexR
    AlexR Member Posts: 61
    what's it measuring?

    What are you measuring?  That looks like temperature somewhere near your boiler?  How often does it sample? 

    I'd guess you could see a difference with less venting in that the boiler will be hot for longer (longer burn to transfer same amount of heat to house), but it may be hard to see unless you zoom in a lot so you can see each peak getting a few minutes wider.
  • crash2009
    crash2009 Member Posts: 1,484
    Probe location

    I jammed the probe into the space between the boiler vent stack and the chimney mortar.  The Lascar is sampling every 2 seconds.
  • Not sure

    A devil's advocate in me says that it may be hard for your to spot a repeatable, consistent difference. "while other factors remain the same" is the core of the problem if you cannot control the weather.

    Also, I am quite convinced that the varying venting capacity will result mostly in a varying comfort levels as long as you do not suffocate the vents way too much - i.e. with fastest venting, all your rads will get steam at the same time, with slow one, the closest will start heating fastest and you will get uneven heat; or you will be experiencing bigger temperature swings in your heated rooms. The energy spent in extra burning time cannot get lost but it will work as a hard to control momentum of the system.

    My 2c bottom line - there will be differences, but figuring out real $$$ savings may be difficult just from that one chart.
  • crash2009
    crash2009 Member Posts: 1,484
    Any other suggestions?

    Here is what I was planning to do.   First of all wait for some stable weather.  I'll record 24 hours with all ten vents, then cut em down to four, continue recording for another 24.  The Lascar will have a continious 48 hour chart.  As long as the weather remains stable, the results should be accurate.
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2011
    Gerry! Your'e a Genius

    I decided to skip the experiments and just let it run.  I don't care what it cost or how long it takes to ROI.  Maximised Main Vents are fantastic.  I mistakenly had thought that maxing the venting was going to magicly remove the air in my mains in an instant, and that that would be measureable in $$$.  Not only was I wrong about that, I wasn't even thinking about the risers and runouts. 

    These Venting Stations not only cleanout the mains, they cleanout the risers.  I am sure that they even reach into the radiators and take a little cold air out of there too. 

    I was manually recording the run cycle, like I always do, using the Hoffmans clink as my signal to write something down.  Did it over and over again, about 20 times.  Then I was reviewing my notes a couple days ago and noticed a pressure rise from .04 to .11 with no notes beside it.  So next cycle I started writing down the time of .04 psi, .05 psi, .06 psi, etc.  Then it hit me like a slap in the face.  Thats the radiators filling up, all of them at the same time.

    This place has a lot of distribution pipes (I estimate) about 75' of 2" main, 75' of 1.5" main, 150 feet of 1.25" risers. 

    Thanks again Gerry
This discussion has been closed.