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Bigger vent for radiator

Hi everyone, could someone tell me what vent would let out more air than a hoffman 1A. I have a large radiator on 3rd floor that doesnt get the air out fast enough with a hoffmn 1a. I have 2 gorton #2 on my mains. It just this big radiator on third floor i have problems with and i know if i could put a bigger vent in it would fix. Just not sure what to use? Thanks for any help.


  • BobC
    BobC Member Posts: 5,473
    C's or D's - but

    The hoffman 1A maximum is 0.145cfm. The gorton C and maid O Mist C are both rated for 0.275 or so. The Gorton D and Maid O Mist D are both rated at 0.330 CFM.

    Those are very aggressive vents that might cause other problems. You might have luck dialing some of the other radiators down so the steam finds it's way to the 3rd floor faster.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Rod
    Rod Posts: 2,067
    Larger Capacity Vent

    Hi- You could try a Gorton "C" which is twice the venting capacity of Hoffman 1A on setting 6.  Gorton vents are available at Pex Supply on the internet.  Unlike main vents, if you vent your radiators too fast it can lead to problems like water hammer.  You might also want to check the slope of your radiator to see if it is slightly sloped towards the inlet pipe.

    If you have an extra Hoffman 1A vent and want to see what doubling the venting would do, put a short 1/8 inch pipe nipple on the radiator vent hole, add an 1/8 inch pipe tee and attach 2 Hoffman 1A vents to the tee.

    - Rod.
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2012
    As Rod and Bob said

     it might cause more problems than you all ready have but I suppose you could always plug the hole.  I improved my 3rd floor rad by adding a Gorton D, just before the radiator.  At the same time, I added a bit of insulation to the runout-where it connects to the main.  Installed a second Gorton D on the other end of the radiator.  And resloped the rad and runout to riser.  The runout is still a little flat, but it drains ok.

    By the way, the TRV didn't help my situation.
  • kcopp
    kcopp Member Posts: 4,393
    and/or you...

    could add another vent. Drill and tap out one either next to or above the other vent....
  • Bigger vent

    What sort of main vents do you have? I am sure your problems come from inadequate main venting.

    Can you hear the radiator vents squeeeeezing the air out?

    The main vents do all the work in partnership with the fuel company, but the difference is that the main vents work for free. The gas company, on the other hand will charge plenty to remove the air. The more main venting you have, the less work for the fuel supplier.

    The result of inadequate main venting is an unbalanced system, such as you describe.--NBC
  • Thanks

    Thanks for all the help. I have 2 gorton #2's on my main. This is a 3 unit apartment building. Lately my 3 rd floor radiators dont get hot at all when temps are warmer. Around 40. If i pull out the vent completely it starts getting hot instantly. Maybe my hoffman is clogged? How can i tell if my hoffman is working? Could my gortons not be working? Should i add more to my main vents. Thanks
  • Having a problem tonight!

    Just talked to tenant and she says radiator not getting hot at all. 1st and 2nd foor is. I had them pull the vents out completely but they still say no heat. Valve is open and last time i check radiator was pitched correctly. This is a one pipe system. Can the inlet pipe get clogged?
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2012
    Just for tonight

     to save your sanity, turn the thermostat up.  This will make the boiler run longer and give the farther rads more time to get some steam.

    Another quick (but temporary) fix is to remove the radiator vent, and vacuum the hole.  The vacuum cleaner will remove the air from the pipes and the steam will follow.  If you can't be there yourself, you could tell the tenant to just vacuum the hole of the radiator vent, it's slower but safer.  The vent will close when the steam gets there.
  • venting the top

    i have hoffman 1a's, and 40's on my lower levels; but some on the third floors have gorton d's. if you vent the top quickly, make sure the lower ones are slow.

    you may still need more gorton 2's [i have 4 or 5 on each of 6 dry returns [55 rads]. the back-pressure of venting needs to be a couple of ounces or less for the air to make a speedy exit when the steam is coming up.

    when you check tomorrow, set the thermostat way up, and see if steam finally gets to the top floor. that would indicate that it is a speed of steam arrival issue.--nbc
  • Gorton 2 with water

    Maybebi add gorton to my main. This is a one pipe system. No dry returns. Recently checked the gortons on my main and was able to blow through them but they did have a little water in them. Is that ok? I will look into the gorton 4. Thanks
  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2012
    Blow test

    You need to blow test "right side up" and "upside down"  Upside down should be impossible to blow anything through.  Right side up, you should be able to blow for a bit, then the plug locks into place and you cant blow through.

    Maybe the vents are stuck open.

    If your new vents are full of water, are they up on an antler?  How is the insulation on the main?
  • Thermostat Location Location Location

    Where is the thermostat in the building?--NBC
This discussion has been closed.