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Extractor fan ducting length?

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  • 25-05-2009 12:55pm
    #1
    jdpl28
    Banned (with Prison Access) Posts: 186 ✭✭


    Hi, I'm installing an extractor fan above the hob, and need to run quite a long length of ducting to vent it to the outside. Should I be thinking about installing a second fan somewhere in the duct? Would the long length provide too much back pressure on the fan & prevent it from working properly?

    thanks,
    J


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    #2
    lastbuilders
    Registered Users Posts: 302 ✭✭lastbuilders


    What length willl the duct be. I am not an expert but we have a duct of about 6 meters from our ectractor and have had no issues with it.

    Lastbuilders


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    #3
    ART6
    Registered Users Posts: 2,632 ✭✭✭ART6


    jdpl28 wrote: »
    Hi, I'm installing an extractor fan above the hob, and need to run quite a long length of ducting to vent it to the outside. Should I be thinking about installing a second fan somewhere in the duct? Would the long length provide too much back pressure on the fan & prevent it from working properly?

    thanks,
    J

    It's bends that reduce flow more so than straights, so avoid too many bends and you can have a pretty long duct without problems. As Lastbuilders says, 6 metres or more wouldn't have any issues, but if you have to wind the duct around too much then it might become another matter!


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    #4
    jdpl28
    Banned (with Prison Access) Posts: 186 ✭✭jdpl28


    will be about 4-5 metres anyway. with a few bends in it - about 6 bends. I'm running it through sewer pipe.


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    #5
    Carlow52
    Closed Accounts Posts: 2,389 ✭✭✭Carlow52


    jdpl28 wrote: »
    will be about 4-5 metres anyway. with a few bends in it - about 6 bends. I'm running it through sewer pipe.

    check what size is recommeneded by the makers, most now are 5" or 6".
    sewer will be much better than the spiral crap


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    #6
    GreeBo
    Registered Users Posts: 27,177 ✭✭✭✭GreeBo


    might be worthwhile insulating it if its a long run, if it cools down before the vent it will dump more grease in the pipe.

    +1 on not using spiral "crap catcher" pipe


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