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  1. #1
    Join Date
    Sep 2004
    Posts
    389
    Hi,
    I've included a pic of 2 diffusers , one on top of the other. The one on top(older one) had flat vanes, so air rises unrestricted........
    The lower one which is a Hart and Cooley 411 has "U" channels on the vanes when looked at from underneath.....I know I am being so darn nit picky, but do you think there is a measureable difference in airflow between the two?
    Thanks
    George


  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,399
    The 4x10 411 has face area of 29 sq inches, the 421 only 27 sq inches. At 600 fpm velocity, both are rated the same at 100 CFM. The 411 is definitely the better register but more $$ of course.

  3. #3
    Join Date
    Sep 2004
    Posts
    389

    reply

    I'm sorry I mixed up my numbers, the one on the bottom is the regular 421 floor diffuser. The one on top "looks like" the deluxe Hart and Cooley(411) model.
    Wondering if it's worth it to repaint my older diffusers for more air flow?
    GeorgeI guess I could ask to upgrade and pay the diff., if worth it.

  4. #4
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    I am sure that you could not repaint this difuser type & get increased air flow!
    just buy new ones!, esp if in floor --
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  5. #5
    Join Date
    Sep 2004
    Posts
    389

    reply

    I do have new ones(the bottom pic), but I'm wondering if I'll have better air flow with the top pictured ones(because they do not have the U channels that you can see in the vanes.
    Thanks
    George

  6. #6
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,403
    I would bet the scooped vanes would increase air flow.

    My theory is the same as turning vanes... it would direct the air for better throw rather than cause turbulence like the straight vanes would.

    Just my guessing out loud though...
    "If you call that hard work, a koala’s life would look heroic."

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    Testo... you guys rule!

  7. #7
    Join Date
    Sep 2004
    Posts
    389

    reply

    That's interesting.....I actually have put the 2 in back and forth and tried to judge the amount of air hitting me, but it's hard that way, because of diff. angles and the direction that they throw the air.
    George

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