Extractor fan ducting length?

jdpl28

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

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

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!

jdpl28

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

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

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