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Read Dan's book, did the charts, have newbie questions

daveodaveo Member Posts: 6
Hi all. Thanks for being here! I'm a homeowner trying to "reset" a single pipe steam system (grew up on This Old House, so I'm very DIY). I've read Dan's "Greening Steam" book, "cranked it down" and now working on balancing. I'm hoping for a reality check before I buy a bunch of wrong spec vents because the flow numbers I have are a lot higher than some of the cheap vents that were on it.

I have 8 rads from .4 to 1.5 cu.ft. (sq.ft. EDR from 16 to 60 if I did it right) and I'm figuring on 3 minute venting. This brought me to .13 to .22 CFM vents as my calculated target and possibly Gorton 5 through a bit more than a Gorton D.

Do these numbers seem make sense so far for a modest 2 story house with a Utica PEC150 boiler?

I can post my calcs if somebody thinks it would be worth looking at.
I also looked at @Dave0176 's chart and it looks pretty close to what I did.


  • SteamingatMohawkSteamingatMohawk Member Posts: 350
    3 minute venting times .13 = .39 cuft and .22 = .66cuft. What about the 1.5 cuft, or am I missing something in your calculations

    You need to provide more info, like the size and length of the piping, both mains and supplies to individual radiators.

    Post what you have done, then the real experts can review.

    Also, can you point me to @Dave0176's chart?

    I have been working on my 90+ year old 2 family for several years and learned a lot about venting. Recently, I created a chart that compares the venting capability of several brands of vents. I haven't posted it yet, because I need to write the discussion that explains the chart.
  • Jamie HallJamie Hall Member Posts: 14,792
    Here's Gerry Gill's excellent commentary and chart of venting -- most of the vents you will see are in there somewhere. Might save you all some time...

    The basic principle of venting is actually pretty simple: vent the mains fast, and then adjust the radiators as needed to get even heat -- or the amount of heat needed in that space. There is no need to go really bananas about venting the mains -- although it's nearly impossible to over vent them, vents do cost money. Steam simply won't travel in a cold insulated main much over 10 feet per minute (it can be a lot faster in one which is already warm -- perhaps twice that).

    Balancing the system can get interesting -- and perverse -- and take some experimenting. The general rule, though, is to start somewhere (and your approach is as good as any) and then slow the radiators which are over-enthusiastic.
    Br. Jamie, osb
    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
  • SteamingatMohawkSteamingatMohawk Member Posts: 350
    Here's the chart I made using the data in the report @Jamie Hall just posted and some information from the MO'M website.

    The notes at the top are key to a full understanding of the range of capabilities for the adjustable vent valves. I plotted the brands most frequently mentioned on HH.

    Quick summary for those not interested in the chart.

    VentRite #1s can go from no venting to the equivalent of a #5.

    Heat Timer Varivalves do not completely shut off and go from a #5 to more than a #1.

    This should help you.

    Erin Holohan Haskell
  • daveodaveo Member Posts: 6
    @SteamingatMohawk, the spreadsheet I was referring to is here:

    I'll post my calcs shortly (sneaking a look during work hours)

    @Jamie Hall, I had looked at Gerry and Steve's sheet and wasn't sure if I should use 1, 2 or 3 oz, so I was looking at 2 oz since 1 oz vent ratings seemed a bit small to my untrained eyes.

    I only have about 30ft of main with a B&J monster at the end of the return (I don't see the model number, but the hole is about a half inch and seems very happy to do the job). A like minded friend of mine had that in a drawer and donated it to my cause along with several Vent-Rite #11s (which I haven't used yet) :smile:

    Over the weekend, I dropped the pressuretrol from 1psi cut-in and 1.5 diff to .5 cut-in and 1 diff and that seemed to do wonders. The B&J stopped spitting as much before closing and the rads seemed to relax a bit. That is when I started looking at the vents which seem a bit all over the place. I've seen some other corner cutting in the house, so off brand vents didn't surprise me that much.
  • daveodaveo Member Posts: 6
    Thank you, gentlemen (especially @DanHolohan ) for the help. Here is a screenshot of my worksheet. I hope it makes sense.
    I used many numbers from Dan's Greening book and lookups from Gerry & Steve's spreadsheet (above in @Jamie Halls comment) and cross checked with the table @SteamingatMohawk included above.

    I haven't seen anything that makes me the wiser if I should be looking at 1, 2, or 3 oz for vent volume, so I used 2 and 3 in the table for comparison.

    I'd appreciate an idea if it looks like I'm doing anything wrong here or if I'm on the right track.
  • KC_JonesKC_Jones Member Posts: 4,557
    For vent volume, I always look at 1 ounce and assume it’s lower than that.  Remember to get those pressures you, to an extent need to under vent to restrict things.

    If you can vent a 60 EDR in 3 minutes, I’ll eat my hat.  I have a D vent on a first floor rad with 50 EDR and it typically only fills on the coldest days, which would be ~20 minutes of run time per cycle.  I’ve had a #6 on this rad which seems to make minimal if any difference.

    I would also suggest that putting those big vent on all the rads is going to cause some control issues.  I’d start much smaller and work up as necessary.  Might end up with a spare vent or 2, but will be easier to get balance.  There are also the adjustable orifice Maid O Mist vents, which are liked by several on this site, I’ll let them comment.  @ethicalpaul
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Jamie HallJamie Hall Member Posts: 14,792
    Agree with @KC_Jones . Start small on the radiators. If you're main venting is adequate, that will work. If you need more heat from a radiator, and you have started small, you can increase that one -- but be aware that will affect others as well, so take small steps -- and only do one at a time.

    As to pressure the same. Use the 1 ounce table, and don't fuss about timings.
    Br. Jamie, osb
    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
  • ethicalpaulethicalpaul Member Posts: 2,528
    I do like the MoM. I don’t call them “adjustable” but I call them “easily swappable”. To me they are a much less expensive and easier to swap Gorton. 

    If I were to advise a friend I’d always say buy enough #4 for the first floor rads, then buy 1/2 #5 and 1/2 #6 for the second floor then see how those do. 

    If a room is too cold, then bump up the size by swapping the MoM orifice on top of the vent

    If a room is too hot and has a #4 on it, cover some or all of its radiator rather than try to do something like making all the other vents faster

    I don’t value the math very much. Too many variables 
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • acwagneracwagner Member Posts: 507
    edited January 6
    Actually calculating the time it takes is far more complicated than just the volume of air in the pipe. The air has to over come the frictional resistance of the pipe walls, which varies with pipe size, number and type of fittings, roughness of the interior pipe surface, and pressure. So each pipe run will vary depending on those factors.

    Also, the pipes have to come up to temperature first. So, depending on the starting temperature of the distribution piping, venting might not be the limiting factor.

    I see those calcs as a good rough guess to start with for initial sizing, but ultimately trial and error is the only way to truly balance it, in my opinion. So, put some vents on and see how it works and adjust from there.

    I also recommend doing the balancing during a "typical" winter day for you in terms of outside air temperature. This will be the most common condition for piping temperature (based on how often the boiler cycles) and how full your rads need to be to keep each room comfortable.

    Since the venting strategy is fixed (as in you're not changing it throughout the seasons) when the outside temp is warmer or colder the system will respond differently. So trying to balance in the fall, for example, might not get you what you want when winter hits.
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • SteamingatMohawkSteamingatMohawk Member Posts: 350
    I called MOM and was able to get a set of orifices, free, if I remember. The rep was very accommodating. Now, I have an abundance of orifices to make any needed adjustments if I make changes in the system.

    Agreed, there are lots of variables as stated above, but it's a good starting point and for comparison between vent valves of what may be needed, especially in the lower CFM range, where an adjustable valve, like the VentRite #1 may be a better choice.

    This stuff is not landing a man on the moon next to the American flag, it's more like sticking your elbow in a bucket of water to see how hot/cold it is.
  • SteamingatMohawkSteamingatMohawk Member Posts: 350
    In my house, I found there is a significant effect of the location of the lone thermostat on how that room warms up compared to the rest of the house. Fortunately, I have a wireless thermostat that I can put anywhere I want without having to mess around with wires.

    Since there is only one thermostat in the converted 2 family (now 4 units), I put the thermostat in the coldest room (second floor, north side), then tweaked the vent valves. It is working well.
  • AdmiralYodaAdmiralYoda Member Posts: 234
    I recently performed the same calculations you did.  I increased the venting dramatically to MoM a #5, some #6's, a C and a D.  Also upgraded the main vents to big mouths.  I was previously using Ventrites #1's.

    No problems whatsoever.  I get heat quicker and everything is balanced.  No gurgling, spitting or anything from the radiators.

    I'm a fan of venting as fast as you can without running into problems or getting unbalanced.
  • daveodaveo Member Posts: 6
    I appreciate all of the help here! I'm going to put in an order shortly. I'm pretty comfortable with the main, partly because the B&J monster doesn't seem to spit anymore and I haven't had to add any water in quite a while! Also, the rads still need balancing, but the temperature through the house is noticeably more even.

    I'll get a few Gortons for the big rads, but, as mentioned above, I'd like to see if there are recommendations on where to buy a couple of vent-rite #1s for the not so big rads. I had an order in for some Gortons (the supplier will let me trade for other Gorton models) based on the old vents, but I have come to find that previous owners didn't put in quite the same time for research and I've gotten very valuable information here!

    Vent-Rite vs Emerson Swan vs Hoffman

    I think I saw another discussion in the forum on Vent-Rite vs Emerson-Swan and not sure what the thoughts are. Is a Vent-Rite #1 the same as an Emerson-Swan #1 ($45 on Amazon)? And are they the same as a Hoffman 1A ($33 from my supplier)? And is there a better source for small quantity purchase?


    On a related note, should I open a new discussion to ask about sandblasting and powder coating in the Northern NJ area? My wife is looking to improve the look as we are tossing some old, really ugly, enclosures and what is underneath hasn't had any decent attention for too many years.
  • daveodaveo Member Posts: 6
    edited January 8
    So, I take back part of my question. I still would like to know the Vent-Rite vs Emerson Swan part, but I see from Steve and Gerry's chart that the Hoffman 1A has a very different (wider) range of settings and looks like it could be better for my situation since I'm in early stages of balancing.

    Does that make sense?
  • SteamingatMohawkSteamingatMohawk Member Posts: 350
    If you look at the chart I posted above, a "simple" solution is to use VentRite#1s for the lower required capacities and Heat Timers for the larger needs. I have no experience with Hoffman's, so I didn't even consider plotting them.
  • acwagneracwagner Member Posts: 507
    I used Hoffman 1A's initially when I balanced my system. They are good vents, and are adjustable for a decent range so it's easier for a novice to balance the system without spending a lot buying multiple fixed vents to swap around. The only drawback, in my opinion, is they make a "click" noise when they operate. Some people are bothered by that.
    Burnham IN5PVNI Boiler, Single Pipe with 290 EDR
    18 Ounce per Square Inch Gauge
    Time Delay Relay in Series with Thermostat
    Operating Pressure 0.3-0.5 Ounce per Square Inch

  • Dan_NJDan_NJ Member Posts: 160
    I started with a mix of Hoffman 1a and and VentRite, I've retired a few of the Hoffmans, just retired one last week that was waterlogged and leaking steam - put MoM in its place. I know I have wet steam right now so maybe that's part of the problem, and on that specific Rad there's a leveling issue (1/8" tapping is a few degrees south of level, mitigated for now).

    I like the Hoffman click but i find the adjustment is sloppy and undesirable. I'll keep the three remaining unless/until they fail.

    The chart at least gives me a heads up when something is amiss - I've been keeping track weekly for three seasons.

  • daveodaveo Member Posts: 6
    @SteamingatMohawk, Thanks for the reminder, I had forgotten some of the details of your chart (I didn't actually realize that the Varivalve was a unit and not just a comparative scale, for some reason).

    I've swapped the Hoffmans for Varivalves in my order. They don't have VentRites at that supplier and the new mix will just about match the cost of my original (poorly conceived) order that I am returning.

    @Dan_NJ, what are you using to monitor adding water? I'm doing it manually (and can't meter it) right now because the installed feeder gave up the ghost and I didn't replace it (yet) because I'm not comfortable with just letting water just be added quietly and not letting me know if something is wrong.

    I built a monitor for my sump pump (I do electronics projects, too) so I know waterflow there, but not sure how I can automate this for the boiler. Suggestions welcome!

    I didn't need to add water for almost a week (near max value when cold), and then today the level was down to Low Water Cut-Off (cold) early afternoon. If some of my air vents don't close properly, could moderating temperatures today have influenced that? (This is about a 2.3 gallon diff from Max to LWCO)
  • Dan_NJDan_NJ Member Posts: 160
    @daveo I added graduations on the sight glass rod using a sharpie a few years back. I note how much is added (manually only - no feeder in my case) weekly. To do this I filled the boiler to exactly the normal water line level, drew off exactly one gallon and marked that, then added 1/4 gal divisions between the lines. i think I can get to about 1/12 gal accuracy.

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