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Negative Pressure Problem

totung

By totung
in The Grow Room

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totung Advanced Member

totung

Posted
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I have a 440 cfm fan exhausting the flower room.

 

Two of the walls that make up that room are foundation walls.

 

The other two are exposed.

 

I created the room by using one long piece of panda film and wrapping it to make 4 walls.

 

The ceiling was also done, but with a separate piece of panda film.

 

I am having very bad negative pressure problems.  The walls are sucking in A LOT!

 

I have three 6 inch inlet holes that I cut out of one of the walls and stuck 6 inch ducting through, but that didn't help at all.

 

Not sure what to do...

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Guest finallyfree09

Guest finallyfree09

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heres a few ideas...

 

get some cabinet furring strips or some 2 x 2's or something and make a frame around the inside of it.... just like you would frame in a wall but you won't have to be as precise.

 

you know that green clothes line wire? it has a green plastic coating around some wire or cable or something. if you could hook some to the cieling and floor every foot or so all the way around the room and stretch it nice and tight you could make your self a decent barrier.

 

1/2" cpvc would make a good frame work. cheap too. i have used it to make an ice shanty in the past. make the framework and wrapped it with tarp. it might work in your case.... just cut the lengths and stick them together on the inside of your room.

 

i could come up with a million things. i am sure more people will chime in. hope this helps!

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Guest finallyfree09

Guest finallyfree09

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i got it! get the length and width of each wall and put together a pvc frame that matches you dimensions (will be a square shape) and then run a piece of pvc from corner to corner to create an 'x' in the center of the square. stand it up inside your room and repeat for the other wall. bet it only costs maybe 20 bux.

 

you could also make a plus sign in the center of it but i think going corner to corner would keep the walls from sucking in as much.

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SublimeWind Advanced Member

SublimeWind

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the creation of a frame for the room is out of the picture at this point because there is no access to the rafters now that the panda film is up

 

i guess i will try an intake fan to see what that does

 

OSB... Make proper walls, it's not difficult...

 

No access to the rafters? Last I knew Panda was easy enough to cut and tape...

 

Which would you rather do? Spend 50-100$ on another fan? Or buy some OSB and 2x4's (for <50$) and just do it right???

 

I'll help you if you think it's that difficult.. hit me up..

 

And you WANT that negative pressure on the room, it keeps smells IN and going down the vent..

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DT61 Advanced Member

DT61

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Some negative pressure is not a bad thing - ensure you are drawing air into the room through a filter - help keep unwanted guests away and a speed control also helps - and intake would especially if they were both hooked to the speed control so they were balanced.

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totung Advanced Member

totung

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I know I want negative pressure.

 

I thought the openings I cut in the panda film would allow enough air to be brought into the room via the exhaust fan producing negative pressure.

 

Not the case obviously.

 

I was thinking about getting two 6 inch duct booster fans to see what that will do. They are only $23 each and can do 230 cfm each.

 

I figuring I would try that before I frame the room in.

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Guest finallyfree09

Guest finallyfree09

Posted
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i am glad you posted this. i have to put up some plastic with some zippers on it to make my veg chamber a little tighter. the opening is 4' x 5' which means the center of the plastic is gona get sucked WAY into my chamber. would never have even given it a thought had you not posted this.

 

thanks for getting my brain working a little better! :thumbsu:

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SublimeWind Advanced Member

SublimeWind

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I already have three 6 inch inlets and it didn't help at all.

 

Adding three more would probably do nothing also.

 

Just wish I would have framed the room before I hung the panda film.

 

Didn't know I would have this problem.

 

Intake is supposed to be twice the size of the exhaust.. If you are flowing 400cfm out, you need 800 in...

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