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Vent suggestion? Replace VariValve

Hi everyone.

I have a question about finding a fast vent for one rad, so that I can replace a VariValve that is currently on the rad.

Here's the story:

-All other rads balanced... most have MoM #4, and all heat at the same time, quietly and evenly.
-Have wet steam... boiler installed by PO, 8 years ago. No skim port installed. Work in progress.

This one radiator, in the master bedroom of course, is always the last to heat... the line leading to this rad was rerouted during a previous remodel... so instead of going 10' straight up from the main in the basement, it goes over 8', up through an uninsulated exterior wall, and back 8' over to the rad. Much longer run than all the other radiators and the ONLY one in the house where the riser goes up through an exterior wall.

I've tried nice and slow venting, thinking that slow would help the steam heat the cold pipe as it went, preventing condensation and maybe actually being faster because of that. No dice.

I've tried various speeds of vents, most recently MoM #D.... still slower than all other rads.

A couple days ago, I put this old VariValve on... had it saved from when I started balancing what was left by house's PO, and with the valve 3/4 open, the rad FINALLY heats at the same time as the others... and with no water hammer.

What happens, though, as you can imagine, is there's a little bit of water spitting right before the vent closes.

After looking at the Venting Capacity Chart, I tried putting a MoM vent back on, with no orifice at all... just wide open, because it looked as though that might get me close to the same capacity. Again, no dice. Much slower than the others once again.

So, I guess, what I'm looking for is some way to vent as much as a VariValve 3/4 open, but with a float that will prevent spitting. (someday I'll get the wet steam fixed, but that's a larger project)

Attached is a picture of the state of the vent.

I welcome any thoughts/input/suggestions of how to get this puppy vented... keeping in mind I know that dry steam would be better.


P.S. Mains are extremely well vented... both legs fill in 1:45... so that's not a consideration here.


  • neilc
    neilc Member Posts: 2,196
    PO ?
    Police Officer?
    Post Office?
    Purchase Order?

    I wanna see a boiler picture floor to ceiling,
    what pressure are you at?
    known to beat dead horses
  • cnjamros
    cnjamros Member Posts: 75
    Hah! "Previous Owner"
    pics attached.
    Running on a Pressuretrol set to cutout at 2psi, back in at .5. Rarely do I see it cycle on pressure... so probably around 1psi as a rule. Would love a Vaporstat to keep the pressure lower, but that's down the road a bit.

  • jhrost
    jhrost Member Posts: 57
    It might help to use the old trick mentioned by the Deadmen of drilling and tapping a new vent hole above your present vent location. You could use two vents with floats.
  • gerry gill
    gerry gill Member Posts: 3,058
    How about venting the inlet side of the radiator as well as the outlet. This inlet side will close as soon as steam gets there, thereby leaving the regular position air vent to do its job. I have done this before with good results.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • cnjamros
    cnjamros Member Posts: 75
    @jhrost and @gerry gill those are great suggestions... proving that the simplest solution is usually the best. "one isn't enough? use two!"

    I think I will give this a shot.

  • Danny Scully
    Danny Scully Member Posts: 1,397
    edited February 2019
    Another trick and I know it sounds crazy, turn the varivent upside down.
  • cnjamros
    cnjamros Member Posts: 75
    @gerry gill I took your advice and tapped in another vent on the supply side of the radiator. It seemed to help a little bit, not a lot... but the basic idea of this got me thinking... since this runout is more that twice the length of any of the others in the house, maybe I needed to stop thinking of it as a runout, and more like a main run. So, using some vents that I had on hand, and a few fittings that I had to pick up, I created an antler meant to maximize the venting from this 1/8" hole (based on our favorite venting capacity chart)... Photos are attached here. 2 MoM Ds and 2 MoM Cs

    It seems to be working, in that the radiator is filling simultaneously with the others in the house. Still some hissing and gurgling, but that's my wet steam... different project entirely.

    My question for anyone here is, because I'm venting 1.2 CFM, using the 1oz column of the venting guide as a baseline, is there any reason that I can't replace this gorgeous antler of MoMs with a single Gorton 2? It vents 1.1, which gets me close enough, I think, to max capacity to maintain the performance that I've ended up with here.

    Also open to other suggestions. This is in the Master bedroom, so also looking for the QUIETEST solution. :-)

    Thanks everyone!

  • ethicalpaul
    ethicalpaul Member Posts: 4,648
    edited March 2019
    That is pretty glorious, but I think a better way would be to put a relatively large vent on the pipe or maybe off of that top plugged port on the radiator. This is shot from the hip, but I would think a Gorton #1 would be your pal.

    The hissing and gurgling might be because your cold antler is condensing quite a bit before those vents close, and it's tight quarters in that 1/8 pipe (do they call it pipe when it's 1/8?)
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • Fred
    Fred Member Posts: 8,541
    edited March 2019
    When you vent a radiator that fast, steam will race across the top or bottom of the radiator and close the vents before fully heating the radiator. Next heating cycle, feel the radiator top, middle and bottom. Some part of that radiator is likely to not be heated and won't heat because air is trapped in it from premature closing of the vents.

    How long is that radiator run-out and what diameter? If necessary, a vent before the radiator may be appropriate. Leave a slow/moderate vent on the radiator.

    Now that I'm re-looking at your pictures, all those vents are on the same side as your supply valve. Is there a vent on the opposite side of the radiator as well? If not, you are not venting the radiator but you are venting the run-out.
  • ethicalpaul
    ethicalpaul Member Posts: 4,648

    How about venting the inlet side of the radiator as well as the outlet. This inlet side will close as soon as steam gets there, thereby leaving the regular position air vent to do its job. I have done this before with good results.

    @Fred, he was implementing the above suggestion to add venting to the supply side to vent the supply line as you mentioned
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
    EBEBRATT-Ed Member Posts: 13,423
    @Fred read above he was advised to add vents on the inlet in addition to the radiator vent.


    Check the pitch of all the piping on that run out and the radiator. Check the pipe size versus the radiator capacity.

    You boiler piping looks pretty good.

    Maybe you just need to skim
  • cnjamros
    cnjamros Member Posts: 75
    @EBEBRATT-Ed yes, definitely need to skim... however, no skim port on this boiler... looking at getting that fixed perhaps this summer. Until then, just trying to get as close to balanced as I can, knowing the noise/water issues will probably improve once I can skim.

    I will definitely check the pitch on this runout, where it is visible (only about 1/3, unfortunately)

  • Fred
    Fred Member Posts: 8,541
    My bad!
    EBEBRATT-Ed Member Posts: 13,423
    @fred, not bad Fred, good Fred LOL

    easy to miss stuff
  • gfrbrookline
    gfrbrookline Member Posts: 727
    I am a huge fan of Vent-Rites but in your case I am not sure they would help. The don't vent any slower than a MoM #4 unless they are turned essentially off. As an experiment I would turn one or two of the MoM's on the first floor upside down and see what that does to your heat. If that works buy one ore two Vent-Rites for the first floor. That way you can turn them off if you are warm and turn them up on cold days.

    Also to back track a bit, you asked if you could replace the antler on the inlet side of your radiator with a G2, absolutely and it might work better since you have fewer moving parts and a better quality vent.
  • Fred
    Fred Member Posts: 8,541
    edited March 2019
    The answer to putting a Gorton #2 vent on that radiator to replace the answer is actually "no". That 1/8" tapping in the radiator simply isn't large enough to let steam in and water out of the G2. If steam can't hold the vent closed due to water or water can't drain out the vent will likely open and push both water and steam out of the orifice. You can add a Gorton #2 to the supply pipe, if there is room to install a 1/2" tapping. 1/4" tapping may or may not work.