# Push or pull air through a Cool Sun?



## JohnAcres (Jul 16, 2006)

I have a 1000watt HPS, 1 98 cfm 120mm computer fan(exhaust), and a Cool Sun 6" reflector. Currently I have the fan in the door of the room ducted to the hood and is pulling air through the hood with is just open, would it cool the room more effectivly if I placed the fan at the other side of the hood and then duct it out? 

Also I've seen 6" metal fans without power at the hydro store, I was wondering if placed along a point in the duct with a fan attached would it increase the cfm or decrease the temperature at all? I'm hoping to get my digital camera situation worked out, when I do I'll post pictures to make it more clear. Thanks


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## astra007 (Jul 17, 2006)

i think ya are saying that you have a 1000w with a reflector that can be vented if you put in a glass sheild.  correct?  if so then put a 6" fan on it with 6" ducting and pull the heat off the light.  im running 4 in-line with a 8" vortec fan in glass tube sheilds.  works great.  i removed ballasts from room as well and heat is next to nothing.  with no sheild and a computer fan; your wasting yer time, it has to be done right to work, not halfassed.

ducting is cheap and pick up a hurricane fan.  vortec are expensive.  but it has to be commercial grade my friend.  glass is not expensive either.

tip horizonal mount will give ya 50% more light


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## JohnAcres (Jul 18, 2006)

I have the glass and everything set up just currently I have the fan after the light. Like for example,  (iopen 6" duct on hood)->(light)---->(duct)->(fan)(outside), what I'm asking is would it work more efficently to put the fan in the begining, so it would be (fan) -> (light) -> (duct) -> (outside). So that the air would be being pushed over the light instead of pulled.


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## DillaWilla (Jul 18, 2006)

You need to have complete flow thru ventilation, meaning; 1 fan bringing air in through ducting passing through light/reflector out thru ducting and another fan pulling air out.  This is a complete flow thru system.  you dont necessarily need any commercial grade fans.  2 turbo type fans would be fine as long as you attach the ducting the right way.  It takes a little rigging but you can do it without spending a lot of money.  Why dont you post a pic of your setup so we can help you better.  Peace Out and GG


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## astra007 (Jul 18, 2006)

yes i agree with last post.  if you are not using a commercial grade fan like a vortec or hurricane then you should have 2 fans - 1 pushing and 1 pulling.  still think something more powerful then what you are running for both ends.

the more straight yer ducting is the better the air flow and you should be able to mount 1 fan right in the reflector


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## JohnAcres (Jul 19, 2006)

Thanks for the advice, I've just hooked up another 120mm fan as intake into the setup and its maintaining much cooler temperatures than usual even though its unusually warm outside. I should be getting pictures soon and when I do I plan on starting a grow journal, I'll be sure to thank you.


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## astra007 (Jul 19, 2006)

good luck with yer endevor, any other questions, feel free to ask


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## JohnAcres (Jul 22, 2006)

I keep reading the OverGrow FAQ's on ventilation



> *What if I have more than one fan? Should I use one to blow air in and one to **** air out?*
> Not if the object is to provide as much ventilation and cooling as possible.
> 
> · If you have two 3-inch diameter fans, and you mount one in the intake, and one in the exhaust, you have a total intake area of one 3-inch hole and a total exhaust area of one 3-inch hole.
> ...


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## astra007 (Jul 22, 2006)

after messin around with fans and stuff, i found i was wasting to much time on this and not paying enough time on my grow.  i hooked up a hurricane fan and used 6" ducting clamped down on it and reflector.  no problem mon.


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## Mutt (Jul 22, 2006)

Astra your so right. Do the best you can and move on. 
but for discussion sakes.
Wouldn't a negative air pressure situation be the best for cooling.
A higher CFM fan exhaust and slightly smaller intake. As this would create a small vaccuum in the hood and stop any air from generating more heat?

Or would a balanced system be the ideal? Like for a grow room?

Reason I brought it up. was I've been messing with my CPU case and trying to cool it down more. and its sorta the exact physical situation as cooling a hood. its a case and gets hot.


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## astra007 (Jul 22, 2006)

a slightly bigger 1 would be nice but the air has to balance out from somewhere.  another source or over time you would have no air and no plants.   hehehe  seriously, with a bigger exhaust fan for hot air and bottom wall air space would pull cold air into the room.  so a bigger out-take makes sense.


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## astra007 (Jul 22, 2006)

my cpu sits up on my desk - tower.  it has an intake fan at back and vents out the top.  its a HP.  my previous 1 was a IBM and the same set up.  as long as you do not have a heat vent behind it, this works fine.  plus my HP has side jets.  bottom fan intake and upper heat release - no problem

my buddy has his tower sitting on the floor of his apartment and he had heat issues.  i went over and discovered that he lived on the 3rd floor - 2 apartments below made his floor nice and warm thus he was pulling warm air in and overheating.


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## JohnAcres (Jul 22, 2006)

Thanks for your quick responses, I've tried changing the duct but unfortunately right as I did change it the weather changed and became unusually hot so its too hard to tell the difference right now, but I'm planning on keeping it till it cools down. I have a feeling that the one intake and one outake works better though just from the feel of it. Also, my intake fan was 88CFM and my outtake was 98 so I guess  I had the ideal situation described above....

You're truely right about spending too much time on the fan and ducting and not enough on growing. I spent 3 hours today messing around with it trying to figure out the best configuration, only to decide the best configuration was to ditch my current one and just sprint for a real exhuast fan or inline. I'm planning on taking the local hydro store up on their pricematching for planthydrolight.com or something its $150 for a Vortex 6" 449 CFM fan. I figure I'll use it again so its a worthwhile investment =)


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## Mutt (Jul 22, 2006)

For some reason I thought it was an enclosed hood.
Sorry guys. disregard my idea.


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## astra007 (Jul 22, 2006)

i have an eight inch vortec to service 4 - 1000w reflectors and tubes.  if you are planning to go to 3 lights get a 6" ; if not only buy a 4" vortec.


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