 Can You Get Away With Pc Fans As Intake???, cos im cheap innit! |
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 Feb 20 2008, 01:34 PM
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#1
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Vegging Nicely  Group: Full Member Posts: 288 Joined: 24-August 06 Member No.: 15,550 Style of Grow:Organic  |
hey dudes
Question's as above gents! Money is tight for me - very tight. I dont really fancy forking out another £70 on another 4" rvk, for intake purposes. If my grow-space is only going to be 2 x 2 x 5 (all measurements are in feet), can I get away with using maybe 2 PC fans for intake? Specs are 250w HPS, 4" RVK extraction. e-karma for the first person to answer 
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Feb 20 2008, 01:35 PM
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#2
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 Feathered up and living on... Group: Senior Member Posts: 10,851 Joined: 17-October 06 From: ...the dub side Member No.: 17,181 Style of Grow:Not Yet |
Nope.
 
-------------------- "If people only did everything they wanted, everyone would just spend all day sitting on the carpet, watching the poker channel, wanking and eating those expensive German biscuits.......probably." Jez - Peep Show "Build a man a fire and he'll be warm for a day - set a man on fire and he'll be warm for the rest of his life" - Anon. "ĦMake Poverty History - Cheaper Drugs Now!" Frank Gallagher - Shameless |
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Feb 20 2008, 01:36 PM
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#3
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 Custom Member Group: Senior Member Posts: 3,934 Joined: 17-October 06 From: Just behind my nose. Member No.: 17,190 Style of Grow:Hydroponic |
Not sure you'll need one......
But no, you can't use 'em. -------------------- Volcano bags make amazing No-Smell baggies to hold weed in.
Grown here, not flown here. Volcano User |
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Feb 20 2008, 01:51 PM
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#4
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Vegging Nicely Group: Full Member Posts: 288 Joined: 24-August 06 Member No.: 15,550 Style of Grow:Organic |
ooooo okay fair enough, cheers lads. was just thinking it would be atleast a step up from just having passive intakes.
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Feb 20 2008, 02:03 PM
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#5
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Custom Member Group: Senior Member Posts: 3,934 Joined: 17-October 06 From: Just behind my nose. Member No.: 17,190 Style of Grow:Hydroponic |
Depending on your flow through-put, they may actually hinder air flow.
I wouldn't bother even trying. -------------------- Volcano bags make amazing No-Smell baggies to hold weed in.
Grown here, not flown here. Volcano User |
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Feb 20 2008, 02:19 PM
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#6
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 Bud Central Group: Senior Member Posts: 1,565 Joined: 24-February 07 From: From the back of beyond! Member No.: 20,809 Style of Grow:Compost Special Achievements: 
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Use the computer fans to circulate the air inside the room and just run a passive intake, your area is only just bigger than my veg area and I run passive on that with no problems at all!!
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Feb 20 2008, 02:41 PM
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#7
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 Stoned Immaculate Group: Senior Member Posts: 3,663 Joined: 9-October 06 From: The big city Member No.: 16,932 Style of Grow:Compost |
I beg to differ. As long as you have decent extraction, a PC fan makes a useful booster to an intake IME. In a smallish drobe.
It's not ideal to use the same size fan for intake as extract, because the CF slows the extract down, so you need a controller on the intake fan or you'll get positive pressure. This post has been edited by squirrel: Feb 20 2008, 02:43 PM -------------------- |
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Feb 20 2008, 02:46 PM
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#8
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 In Bud Group: Full Member Posts: 636 Joined: 25-May 07 From: down the road. Member No.: 23,140 Style of Grow:Compost |
That area is about the same width and depth as my mom/clone box but I only have a 125 enviro. Maybe try 2 pc fans with a big passive intake in the middle?
-------------------- The Ball's Rolling on my FD 'The Pure' Skunk #1 Diary
My ""True wisdom comes to each of us when we realize how little we understand about life, ourselves, and the world around us." - Socrates |
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Feb 21 2008, 02:59 PM
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#9
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Vegging Nicely Group: Full Member Posts: 288 Joined: 24-August 06 Member No.: 15,550 Style of Grow:Organic |
yar cheers for replies dudes. What size passive intake? If my extract is 100mm RVK.
errrr why has this thread been moved to Growroom Photo's???  Maybe I shouldn't be too suprised at erratic moderator action on a canna-forum 
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Feb 21 2008, 03:16 PM
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#10
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 Resin Coated Group: Senior Member Posts: 2,021 Joined: 27-April 07 Member No.: 22,481 Style of Grow:Compost |
I have a 250w hps in my drobe and I only run my 4" at under 1/2 speed and it keeps my environment spot on.
Passive intakes need to be 5X bigger than extraction. Thats 25cm x 25cm This post has been edited by Jim_jim: Feb 21 2008, 03:17 PM |
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Feb 23 2008, 09:07 PM
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#11
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 Vegging Nicely Group: Full Member Posts: 365 Joined: 25-November 06 From: U.K Somewhere ??? Member No.: 18,237 Style of Grow:Not Yet |
QUOTE(squirrel @ Feb 20 2008, 02:41 PM)  I beg to differ. As long as you have decent extraction, a PC fan makes a useful booster to an intake IME. In a smallish drobe. It's not ideal to use the same size fan for intake as extract, because the CF slows the extract down, so you need a controller on the intake fan or you'll get positive pressure. I agree with Squirrel on this one. I would use the PC fan but also have an extra light proofed hole so that the PC fan is pushing the fresh air in...and the extra hole is acting as a passive just to ensure that the RVK is'nt getting hindered due to the lower air flow coming from the PC fan. |
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Feb 23 2008, 10:57 PM
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#12
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Full Flower Group: Senior Member Posts: 1,012 Joined: 25-October 07 Member No.: 27,012 |
Depends on other factors. Where is the intake air coming from? Do you propose having a CF in the extract?
Passsive intake at 5 times extract size is bollocks. |
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Feb 24 2008, 12:05 PM
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#13
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Vegging Nicely Group: Full Member Posts: 288 Joined: 24-August 06 Member No.: 15,550 Style of Grow:Organic |
thanks for all the interest shown dudes, tis appreciated.
Id have a 100mm CF attached sometime later on, maybe the 2nd week of bloom. so maybe one 100mm PC Fan, plus how big a passive intake? see when you say make it 5 x bigger than your extraction, u mean cutting a great big bloody rectangle out my grobox??? intake air would just be from the surrounding enviroment.... ie my flat
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Feb 24 2008, 01:00 PM
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#14
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 *Cupboard lover* Group: Lifetime Subscriber Posts: 10,635 Joined: 22-November 03 From: Me mum Member No.: 3,681 Style of Grow:Compost Special Achievements:
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-------------------- FDM: C99
FDM: Generals Daughter Cheese vs BB Cheese My WaterFarm Babes PFNC Award winning Growroom 12/12/05 "Dumping the dealer isn't a choice in my eyes, it's the only way for cannabis users to take control." - SR "I plant therefore I activate" - Sleeve |
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Feb 24 2008, 11:15 PM
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#15
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Full Flower Group: Senior Member Posts: 1,012 Joined: 25-October 07 Member No.: 27,012 |
100 Rvk will not deal with the flow rate your need, when you fit a CF. That fan produces less pressure than the resistance of the CF. You will need a 125 RVK L (not the A model.) That will take care of your heat gains from lighting and be in excess of oxygen requirements for your grow. Passive intake is OK with this fan. Something like 200 long by 75 (mm). Passive intake has to be light baffled. RVK 135 is about 55 60 quid.
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