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beastcoast
Stranger
Registered: 03/29/15
Posts: 92
Last seen: 4 years, 7 months
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Exhaust vs intake fan
#21807897 - 06/14/15 08:02 PM (8 years, 7 months ago) |
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I'm ordering a hydro farm 6" inline fan and a variable speed controller so that I can run the fan at 50%, which will prolong motor life and provide the proper rate of air exchange. This fan will be mounted inside my basement window which sits at one end of the 15x7 fruiting chamber, which is enclosed by plastic sheeting. The fan will draw air from outside through a filter, and will be ducted to the other end of the room, where it will enter a tote to be humidified, and then released into the chamber.
But I'm still confused about exhaust. Bringing all of this fresh air into the room will create a positive pressure. Air will want to escape wherever there is an opening. So, do I need a fan to draw air from the room and put it outside? Or do I simply need an opening because of the positive pressure? If I do need the fan, does it need to have the same power as the intake?
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t3chnobily
Strangest


Registered: 02/04/12
Posts: 651
Loc: As Seen In VT
Last seen: 6 years, 9 months
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Re: Exhaust vs intake fan [Re: beastcoast]
#21808008 - 06/14/15 08:26 PM (8 years, 7 months ago) |
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With a two fan system you want to balance the flow so that your room is under neutral or slightly negative pressure. If this room is in the basment of a residential building you do not want to be blowing spores and high RH air into the building envelope. You wan to be sucking it out and blowing it outside. You can route a passive make up air from outside or use a smaller fan to increase the FAE.
6" is over kill for your room. Mine is twice the size and the 6 inch fan is too much unless I choke it down. I'd get the 4 and skip the controller
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Gr0wer
always improving


Registered: 09/16/03
Posts: 6,056
Loc: El Paso, TX
Last seen: 5 years, 10 months
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Re: Exhaust vs intake fan [Re: beastcoast]
#21808022 - 06/14/15 08:30 PM (8 years, 7 months ago) |
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Positive air would keep contamination down especially if your running any sort of filter on your intake. Down side would be any cracks will leak into your basement releasing spores into your basement and humidity.
Negative air keeps the moisture and spores out of your basement but you need a tight grow chamber with an easy flowing inlet into your humidifier tote to avoid sucking unhumidified and unfiltered air from your basement into your chamber.
One fan should be enough.
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beastcoast
Stranger
Registered: 03/29/15
Posts: 92
Last seen: 4 years, 7 months
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Re: Exhaust vs intake fan [Re: Gr0wer]
#21808161 - 06/14/15 09:04 PM (8 years, 7 months ago) |
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the room is virtually airtight. The poly sheeting is doubled layered at the seams, and it's all been lapped with typar tape. The air lock entry way will prevent positive pressure from blowing contains out when the door is opened, but there might be some build up in there over tjme
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Gr0wer
always improving


Registered: 09/16/03
Posts: 6,056
Loc: El Paso, TX
Last seen: 5 years, 10 months
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Re: Exhaust vs intake fan [Re: beastcoast]
#21808809 - 06/14/15 11:45 PM (8 years, 7 months ago) |
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If its that legit id say throw a fan on the exhaust and run negative pressure avoiding cost and tuning of a second fan.
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Toadstool5
A Registered Mycophile



Registered: 01/22/15
Posts: 1,359
Loc: The Golden State
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Re: Exhaust vs intake fan [Re: Gr0wer]
#21849440 - 06/24/15 08:47 AM (8 years, 7 months ago) |
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I say keep the positive pressure going. Every big spawn producer i have heard from uses it for spawn rooms. Its one of the most effective ways oof minimizing fungus gnats, if they get inside you are screwed. The gestation period is like 24hrs!
If you are conscerned with air quality simply "scrub" the air with an air filter that has a pre-filter, activated carbon filter, and most importantly a HEPA filter. Theres no need to have a vent.
If your basement is not moisture-proof then theres not much that can be done to protect it from damage other than proofing it with caulking, acrylic paints, and wood stains.
-------------------- If you do not know where the mushroom products you are consuming are grown, think twice before eating them. - Paul Stamets AMU Teks Stro's Write Ups
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