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Main venting and balancing

amakro15 Member Posts: 39
edited November 2019 in Strictly Steam
So my heating in my 2 story home is not well balanced and trying to figure out how to go about this. I have 3 2inch mains, single pipe system. Shortest main is 20’ long and has 2 Gorton #1’s, next main is 52’ long and has 1 big mouth, last main is 62’ long and has 2 big mouths on it.

The shortest main heats up and vents close fast (approx 10-12mins) and the rads get hot very quickly. The mid length main takes approx 15mins longer to heat up, and the longest main vent takes another 10-15 or so mins on top of that. The last rad on longest main is in master bedroom on 2nd floor and it has a Gorton D on the rad to try and get it hot faster up there before thermostat is satisfied and shuts off. I have to turn the thermostat temp up to give enough time to get heat in my room and it shouldn’t have to take that long. By that time it is sweltering hot on main floor.

Any suggestions on adding more main venting to longer mains and/or using just 1 Gorton #1 on short main instead of 2 since it heats way faster than longer mains?

Also what kind of vents do you recommend or like for radiators? I have a mix between gortons, vari vents, and some really old bottle looking vents.

Any suggestions and help is much appreciated.


  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    You can certainly try taking one of the Gortons off the short main. However, it troubles me that the mains -- all of them -- take that long. Are they fully insulated? That can make a huge difference.

    Also, try slower radiator vents on the radiators served by the short main. Paradoxically, it is often much more useful to slow radiators down which are too fast rather than trying to speed radiators up which are too slow.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • gfrbrookline
    gfrbrookline Member Posts: 753
    I have similar length long mains and I have 3 Big Mouths on each.

    What vents do you have on your radiators other than the Gorton D? That D vents faster than your current main vents. I attempted to use Gorton radiator vents to balance my system and was able to do so but my system lost to much water so I switched back to Vent-Rite #1 adjustable vents. My fastest vent is set to 6 and everything is balanced. You want to vent the mains quickly and the radiators slowly.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    Correction, the D vents at the same rate as your Gorton #1.

    Looks like @Jamie Hall and I were essentially typing the same thing at the same time.
  • acwagner
    acwagner Member Posts: 505
    There is some trial and error to balancing.

    Check out this PDF for balancing system using vents (if you haven't already).


    At the end is a table that covers the venting rates for basically every main and radiator vent made. This will help because you'll be able to compare the relative venting rates of the different radiator vents you have.

    I'd recommend starting by backing off the venting on the short main and the rads on that main, as @Jamie Hall mentioned.

    I see from your older posts that you got a new boiler recently. Have you insulated the lines?

    Also, how was the new boiler sized?
    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

  • amakro15
    amakro15 Member Posts: 39
    Pipes are insulated and I just skimmed the boiler 2x less than a month ago. I do hear the big mouths make light poof/puff sounds right before they close. Is that normal?

    Would it be wise to maybe throw on 1 or 2 more big mouths on both longer mains or am I wasting money?

    I will take off 1 of the gorton #1 on the shorter main and see how that works.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    Yes add the big mouths on the long mains, at least 1 each.

    Don't remove the Gorton from the short main until you figure out your radiator vents and see the impact of the Big Mouths.

    What are you using for vents on all of your radiators?
  • gfrbrookline
    gfrbrookline Member Posts: 753
    The big mouths do let out a little poof of steam before they close, this is perfectly normal, if anything it lets you know it closed when it stops. If it last for more than 10-15 seconds there is a likely problem.
  • amakro15
    amakro15 Member Posts: 39
    @gfrbrookline thanks for the tips. I have a mix of different brand vents on rads.

    I’ve been under the impression Rads closer to boiler should vent slowly and rads further from boiler should vent faster. I will add that with the last rad, the top of it gets hot and bottom is cold. I takes a really long time before entire rad gets hot top and bottom all the way through. I have removed the gorton D vent to check and I’ll get a few droplets of water come out when I turn it over.
  • coelcanth
    coelcanth Member Posts: 89
    amakro15 said:

    I will add that with the last rad, the top of it gets hot and bottom is cold. I takes a really long time before entire rad gets hot top and bottom all the way through.

    that might be an important clue..
    i have not experienced it, but i've read that can be a symptom of overventing a radiator..
    in effect, the steam races across the top of the radiator and closes the vent before it can come close to pushing all the air out of each section and heat evenly.
    try slowing this vent way down to see if it improves things.

    you wrote that it takes about 35-45 minutes to get all three mains hot.. is your boiler going full steam the whole time or is it cycling on and off before it finally shuts down ?

    it'd be worth getting an accurate low pressure gauge to see what your boiler is running at during a call for heat.. it seems counterintuitive, but i've read here that running higher pressures can actually slow the steam in your system down.

    before you go wild spending money on main vents, it might be worth seeing how fast your mains vent with all the vents removed. if running the lines wide open shows little improvement, it might not actually be a venting issue...

    also would be useful to learn how to clock your gas meter, so you can calculate the amount of btu's your boiler is actually using and make sure it matches the specs on your boiler info plate.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    That is the advice Gorton provides, long story sort it's wrong. Radiators need to be vented based on size and proximity to the boiler, as slowly as possible. It's always a bit of trial and error which is why the Vent-rire #1 is such good option. The Gorton D is a problem but the real problem is all of the the radiator vents in line before it are stealing the steam so it never reaches that radiator. I fell into that trap ten years ago and wasted a lot of money before I found this site.

    Fix your main vents then add vent-rite #1's to balance the radiators. Vent them slowly and make sure they heat from top to bottom all the way across. If they don't slow them down a notch until they do, simple as that.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    edited November 2019
    I used Maid-o-Mist vents on all my radiators. They come in the same sizes as the Gorton radiator vents ( 4, 5, 6, C and D), but they're cheaper, and the orifices are interchangeable, so you can swap orifices instead of changing vents. You can even buy a vent that comes with an assortment of all five orifice sizes for less than you'd pay for a single Gorton.

    One word of caution: if you buy them at Home Depot, if the box looks like it's been opened, take the vent out and make sure it really is what it says it is and that it hasn't been used. They have a pretty liberal return policy, and they often return items to stock without inspecting them.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Don’t follow the Gorton advice on venting. Vent the mains fast, and the radiators slowly, at first.
    Later on you can increase the radiator venting for Any slow pokes.—NBC
  • mikeg2015
    mikeg2015 Member Posts: 1,194
    I have a huge pile of Gorton 5,6,C And Ds. I use all 4’s and vent rites now. Most vent rites are set to 4-6, only big radiator a 7. Some radiators close get a little too much and further need a slightly higher setting. But my system is also unusual in the boiler is undersized and I cannot fully heat all radiators anyway. So it’s a little touchy with balancing, especially since it has 1/3 of the EDR on TRVs.

    Get the main vented fast then vent radiators as slow as possible. If you vent too fast the steam races across and never heats the radiator fully. It’s almost like it mixes with the air.
  • amakro15
    amakro15 Member Posts: 39
    Just a little update:

    I decided to time my heat to get more accurate times.

    I took the main vents off my mains and timed how long till steam came out. ***This is from a cold start, heat was not on all day, and it was somewhat mild day today.

    20’ main took 13.5 mins, 52’ main took 18 mins, 62’ main took 20.5 mins. The valve on last radiator on longest main got hot to the touch at 26 mins. I had air valve off that radiator to see how fast it could heat up. At around 42 mins the whole radiator was hot.

    So, with these times I recorded, how can I even these times out a bit? I took off one Gorton #1 on the shortest main after conducting my timings. Would adding another big mouth to each of longer mains help vent them faster? I feel like it does take a long time for that last radiator to heat up once I feel the valve get hot.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    I would put a Gorton #2 on the short main, a Big Mouth on the 50' main and a Big Mouth plus two of your Gorton #1's on the 60'. You may need more but I think that is a good starting place.
    Then slow the radiator venting way down. All of those large vents before the last radiator are stealing it's steam
  • Mike Cascio
    Mike Cascio Member Posts: 143
    Can we see some pictures of the near boiler piping. I have seen bad near boiler piping cause very slow steam production i.e. wet steam.