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Swap out vents

TomH42 Member Posts: 43
Would like to update vents in house.

It looks like like the radiators have Hoffman #40 vents.

Bob C. indicated Maid of Mist O Mist vents may have thread problems.

So, if I were to get new vents, which type and size should I look at? Put a Groton on the main line two years ago and it works well.

I have 5 radiators in the lower level and would like to swap these out.

Here are photos of three of the radiators.

BTW, on a different topic, is it common to have one or two, two pipe radiators with a bunch of one pipe installations? The first photo looks like a two pipe unit (valve and pipe at end not seen) while the others in the house are one pipe.



  • Rod
    Rod Posts: 2,067

    Hi- What wrong with the vents you have now? The Hoffman 40 is a good vent.  They can be cleaned by soaking them in CRL or boiling them in white vinegar.  If you can't blow through the vents  when they're upside down, then the  vent is most probably working correctly. If you need new Hoffman 40 (s) you can get them from a local supplier or Pex Supply on the internet.     A lot of systems are a mix of one and two pipe radiator especially if they incorporate fin tube base board radiators.

    - Rod
  • TomH42
    TomH42 Member Posts: 43
    Good to know

    the Hoffman 40 is a solid vent. Thanks Rod. I will try and clean them. The reason I am concerned is due to constant hissing when the system is working. Each and every vent on the lower level gets in the act.

    Cleaning certainly is cost effective so we'll see how that works.
  • Rod
    Rod Posts: 2,067
    edited December 2012
    Hoffman 40

    Here's what a Hoffman 40 looks like internally.

    - Rod
  • hissing vents

    high pressure is usually the cause of noisy hissing vents, so have a look at your gauge, or get a better one, and dial down the pressure.

    the hoffman 40 is a perfect vent for your system.--nbc
  • TomH42
    TomH42 Member Posts: 43
    High pressure

    is also a problem in the system nbc. Adjusted settings recently so we'll see where it kicks in and out.

    I do know 2 radiators were removed from system during a renovation. The capped unions are visible in the basement. There were 8 radiators now only 6. Plan to calculate boiler size right after cleaning vents.
This discussion has been closed.