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new radiator vents are puffing

Just had the vents on 2 radiators replaced by vari vent type vents. Now radiators huff and puff like the big bad wolf. Puffing is so bad it sounds like my dog is puffing in my ear at night. Also these 2 radiators seem to be last to heat but are closest to boiler line. Was told to regulate their heating by adjusting the number on the vent. Is this correct? Any suggestions about the huffing and puffing issue? Is this normal? They're not hissing or spitting.Appreciate any help. Thanks.


  • Boiler Talk
    Boiler Talk Member Posts: 136
    What was the reason for replacing them?

    What you hear might be some other symptom.  I think the first question to answer for us is the reason you had the vents replaced.  I used VariVents and I had similar breathing sounds.  I had a new system put in, so I needed to clean out the oil in the system.  Did you have other work done on your system? 
  • Fred
    Fred Member Posts: 8,542
    edited April 2014
    Check a few things

    If my memory serves me right, you recently had a new boiler and near boiler piping installed. Did they finally get it right? Did they clean the boiler and skim it properly?

    As to these vents, it may simply be that they used a very small orifice/closed them too much because they are closest to the boiler. Open them a bit and see if that eliminates the puffing. You will need to adjust them in small increments so as to not allow those radiators to over heat those rooms before the rest of the house gets to temp. The other things to check is the Main vents. Did you have those replaced when the new boiler was installed? If so, did they put enough venting on those mains to push the bulk of the air out of the system ? Also, what kind of pressure are you running on that boiler? Cut-in should be around .5psi and Diff around 1psi for a cut-out of around 1.5psi. I think we had the pressure conversation when the boiler was being installed so I suspect that is properly set.
  • plumbergirl1
    plumbergirl1 Member Posts: 14
    radiator vents

    I am the person that has been having one problem after another since having a new boiler installed in November. I continue to have banging, boiler has been skimmed by original contractor , finally bullhead tee removed and a gate valve was finally installed at bottom of mud leg??( per manual) but this bottom mudleg was never flushed out. They changed the vents because these 2 radiators were not heating up  Second time they changed them ( first time was 2 days after install). When they put these new ones on they said they were clogged with stuff, but they didn't skim the boiler again??? I asked why this would happen.. no answer. The vents are opened all the way per their instructions. I recently had a Burnham boiler rep visit and he tells me there is dip in the main for these 2 radiators and it needs to be pitched better. It seems when they repiped one of the 3 times they changed the pitch somewhere in the line. Could this be part of the problem or is it that the boiler is still dirty? How many times does a boiler need to be skimmed . They tell me it's skimmed enough! I've read on the wall that you should have to regulate the heat from the vents on the radiator is that true? They have checked the pressure and said it's correctly set. What is the issue with the main vents? What should I ask about? One main vent blew off in January and was replaced and they were relocated  but one is higher than the other on the side where the pitch is wrong. Should the main vents be even and is there a particular one that is better for venting all the air out. Besides the puffing... when the heat is coming on I hear water sloshing in some of the radiators. I didn't think I should hear water sounds. Am I right?
  • Jamie Hall
    Jamie Hall Member Posts: 22,924
    Huffing and puffing

    and the big bad wolf... and sloshing... and banging... to me points to water being trapped in a main somewhere, most likely on the way to these two radiators (but not necessarily; steam can be strange that way!).

    Check the pitch on every single more or less horizontal piece of pipe -- not just end to end, but all along the pipe.  Sags are bad news... but usually fixable without too much hassle.  Just plain bad pitch may be a bit more of a hassle, but also is usually fixable.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 15,462
    Gauge glass

    In regards to skimming, would it be possible for you to either post a short video of how the gauge glass acts after the boiler has been steaming for a while.

    If not, can you post a picture of what the water in it looks like right now?

    I don't know about others, but I don't trust "It's been skimmed enough!".  Not saying you don't have other problems like sags in the piping and those awful vari-vents, but I figured I'd start at the boiler.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment