Too much negative pressure

georgyboy

Active Member
I have a 5x2x6.5 foot closet that I cool with a 6" inline fan rated at 400cfm. There is some short ducting, a tight turn, and a 6" carbon filter. I have a sheet of mylar with a zipper in it as a door. I have an 8" intake at the bottom. When the fan is on it sucks the tarp in very hard. It wouldn't be a problem but the strength of the pull keeps unsticking the zipper from the mylar. What is a more appropriate intake size for this setup. Would adding a 4" intake, or 2, above the 8" one be effective?
 

Unlimited One

Active Member
250 cf_.. 10" max fan by can fans= 1019 cfm 815 filtered. I wanted to put that as an exhaust in a 4x8 tent. Tornado, shit. Should I just use the max fan to cool both 600w xxxl hoods. Will that be overkill for the hoods? New newbie. All comments/opinions/ appreciated.
 

Adamrl018

New Member
250 cf_.. 10" max fan by can fans= 1019 cfm 815 filtered. I wanted to put that as an exhaust in a 4x8 tent. Tornado, shit. Should I just use the max fan to cool both 600w xxxl hoods. Will that be overkill for the hoods? New newbie. All comments/opinions/ appreciated.
get your own thread?
 

georgyboy

Active Member
Yeah guys I have a fan speed controller. I forgot to mention I am trying to get my temps down. They sit at 95F with a 250w and some CFLs in there.

Unlimited One, you came on to my thread, did not even acknowledge my original question, and asked a question of your own that had nothing to do with the OP. You posted in the wrong place man. You start your own thread for your own question. It's the "manners" of forums.
 

georgyboy

Active Member
also superstoner1 an 8" hole would have surface area that is A=4^2xpie=16x3.14=50.24". A fair comparison of an 8" intake is an 8" square intake which would have a surface area of 64". Square shapes still offer significantly better surface area than round ones but it is not as drastic as you implied. A round hole with a surface area of 25" would be a little less than 6". I'm talking diameter of course, not circumference.
 

ghb

Well-Known Member
put a passive vent on that thing, problem solved, no need for expensive speed controllers that damage the motor in your fan.
 

Unlimited One

Active Member
Yeah guys I have a fan speed controller. I forgot to mention I am trying to get my temps down. They sit at 95F with a 250w and some CFLs in there.

Unlimited One, you came on to my thread, did not even acknowledge my original question, and asked a question of your own that had nothing to do with the OP. You posted in the wrong place man. You start your own thread for your own question. It's the "manners" of forums.
Yea I realized that after I posted the question. I was new, and still am to this site and forums, and didn't know what I was doing, and being that it is your thread, I agree with the "manners" of forums and apologize for intruding on your thread. I also believe that part of the "manners" of forums is to inform someone in a respectful manner if they fuck up and not in the smart ass "get your own thread" way. But you are right I did act like a child, and now that I know a bit more how this forum stuff work, and a "manner" of such forum, I will be sure not to make the same mistake. My sincere apologize to you georgyboy, adamrl018, and thebugslaaaa. Godspeed on your grows.
 

georgyboy

Active Member
Yea I realized that after I posted the question. I was new, and still am to this site and forums, and didn't know what I was doing, and being that it is your thread, I agree with the "manners" of forums and apologize for intruding on your thread. I also believe that part of the "manners" of forums is to inform someone in a respectful manner if they fuck up and not in the smart ass "get your own thread" way. But you are right I did act like a child, and now that I know a bit more how this forum stuff work, and a "manner" of such forum, I will be sure not to make the same mistake. My sincere apologize to you georgyboy, adamrl018, and thebugslaaaa. Godspeed on your grows.
Apology accepted bro. Don't sweat it.
 

georgyboy

Active Member
Can you rig a small light maze or something and try opening the bottom of the zippered door?
I have tried leaving the zipper door open and oddly enough temps rise directly below the light. I assume it has something to do with the way the air moves around inside the closet. I took a 6" duct fan that I had lying around and attached it to an elbow and just set it inside the 8" intake. It's not sealed or anything just sitting there blowing in, and it has dropped the temps to 88F which i'm much happier with and it has relieved some of the negative pressure. I am thinking about getting an 8" duct fan and elbow and fitting it to the intake to see how that goes. If I can get the temps down to 85F, with ambient temps at 75-79F, then I am satisfied. It's the hottest time of the year so I figure if they are 85F now then I shouldn't ever have a heat problem through the rest of the year.
 
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