Ventilation

[emptypackofcigs]

okay i wanted to know if i was to build a cab... 3' x 2' x 6'... what would be a good size fan for ventilation.... 140cfm? 200cfm? 500cfm? anyone know please clue me in... peace

 

[bombbudpuffa]

Depends on what size light you have, what kind of light it is but i'd say 140 cfm would do it but go with the 500 if you can. The more the better. I have a 265 cfm fan in a room thats 2x3 1/2x8.

 

[Dada]

Had to remove.

 

[emptypackofcigs]

okay i'll show you what i was thinking give me a few min to draw it up

 

[emptypackofcigs]

so this is what i have planned to build... its pretty much self explanitary... if you have any suggestions or questions i'll be more than happy to answer.... oh and btw ... its a 400 w HPS light and i wanted to get a squirell cage fan for the bottom fan... but i wanted to know about the fan for the ventilation to go through the carbon scrubber... i would mount it right on the outside of the box and have the dryer hose attached to it and the carbon scrubber... good idea?

 

[Bubby]

You'll have to be careful about how air leak-proof your box is. Because you'll be pushing air in the cab, the air will go for the path of least resistance, which means you might end up with stinky-drafts coming from the seams of your box.

I think a better way to do it would be to move the fan next to your carbon scrubber. This way it'll be pulling air in, giving your box negative air pressure (no smells), and most of the intake should still pass through your cooling system. You could also position the dryer piping so that's it's pulling air in right next to the hot bulb.

edit: Oh dear, I'm too profane.

 

[emptypackofcigs]

YA thanks... but what size should i use... since it will be pulling now... about 256cfm? or should i go as far as 500 if i can?

 

[Firepower]

more air = more circulation = cooler temps

 

[Bubby]

Your box size is 32.5 cubic feet, and I've read that *'optimal' air exchange is around 10 to 15 times the size of your room per hour. So assuming perfect airflow, you'll want 325 - 487.5 cfh, or 6 - 9 cfm. A small fan indeed!

Not only are you cooling a 400watt hps, but will be pulling through a cooling system, and pushing through a carbon scrubber, which'll reduce airflow (though we don't know how much). I think the smallest squirrel cage fan you can find will do more than enough.

*Air exchange is referred from here: http://www.growdiary.com/marijuanacultivation/marijuanahydroponics.html

 

[emptypackofcigs]

thanks very much buddy... thats all i needed to know... i actually think i'm going with a 80cfm inline ducting fan or maybe a 250cfm ... i think the 250 its in my price range and size range... so thanks very much