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Balancing radiators

panick007 Member Posts: 24
edited February 2023 in Strictly Steam
I recently installed a new boiler, which I documented in an earlier thread. Thanks to everyone who offered knowledge, advice and support. Respect to all of you who routinely muscle those big wrenches and pipe fittings around!

My boiler has the factory supplied 30# gauge and I've also added a 2# gauge and a Dwyer Magnehelic -5-0-5.

The pressure when the system is warm is between 2 and 3 ounces. It occasionally hits 8-1/2 ounces if the system is cold.

I've been reading (and re-reading) "Balancing Steam Systems" by Gerry Gill and Steve Pajek, and also the chapter on Venting in Dan's 'The Lost Art". I've also been reading a lot of post's here and it sounds like what I want to do is vent the mains fast and vent the radiators completely but not necessarily fast.

My system has 2 mains, both mains are 2" pipe. Main1 travels 50' from the header til it drops into the dry return, Main2 runs 23'. Initially Main1 had a single Gorton #1 and Main2 was not vented. I bumped up Main1 by adding 2 Gorton #1's (3 total now, all new) and I installed 1 on Main2. There are 2 risers going up to the 3rd floor (1 off each main) and I added a Gorton D to the top of each of those. Main2 fills with steam a bit faster than Main1, 3+ minutes.

The majority of the existing radiator vents are either Dole-a-matic Super 1933 (adjustable and sadly not included in the testing noted in Balancing Steam Systems) or Dole VariVent 1A (adjustable) and they were already installed when I bought the house 20 years ago. I have replaced a couple of those with Gorton.

All my radiators are American Peerless Column type except for 1 small, new thin-tube type in the powder room and a radiant type in the kitchen.

I plan to replace all the adjustable vents with new and I’ve put together a drawing and chart listing each radiator, which I'll attach in case anyone is interested.

Am I approaching this the right way? According to my math the smallest vent will be a Gorton 5? Should I slow it all down and drop each vent by 1 size?


  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    Venting one pipe steam is one part math -- and about 10 parts magic. You've got a very good start with your mains. Now the trick is going to be to get the balance on the radiators, and that is simply going to take time. I'd probably slow all the radiators down myself, and then see which spaces are colder than I'd like and speed them up, but only one space at a time.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    Nice sketch. Where are the main vents located?
  • panick007
    panick007 Member Posts: 24
    I uploaded the wrong version of the sketch, here's the one with all the details.
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
    Nice, do the wet returns connect below the water line? If not, depending on the distance to the #1s the shorter main might be venting through the longer mains #1s. I had that exact problem with my system, but the main vents on the returns were about a foot apart.
  • gfrbrookline
    gfrbrookline Member Posts: 753
    Do yourself a favor and drop the Dole vents they are unreliable in their setting unless set up perfectly. Go with gortons set up to the gerry gill chart that can ge found on this site. Much more reliable.
  • panick007
    panick007 Member Posts: 24
    @SteamingatMohawk Yes the wet returns connect below the water line, just before the Hartford Loop. I tried to indicate that on my sketch but didn't make a note of it.

    @gfrbrookline My plan is to replace all the Dole's with Gorton's
  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,005
  • exqheat
    exqheat Member Posts: 185
    I prefer Maid o mist. You can change the vent opening if needed.
    John Cockerill Exquisite Heat www.exqheat.com Precisions boiler control from indoor reset.