# do you push or pull (air in cooltubes)



## astrobud (Nov 4, 2009)

so what do you , push or pull the air from the fan in the cooltube. i had a 240cfm that seemed to pull better than push but it quit working, im getting a better one that has 448 cfm(vortex style) and was just wondering how my friends here do it:hubba:


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## greenthoughts (Nov 4, 2009)

Hi Astrobud,
     When I ran air cooled lights, I also found that it pulled much better than it pushed air imo.  I tried it the other way around first and quickly decided it had to be better the other way. A 448 cfm fan should be sweet.  I had good results with a 265.  Hope that's what you were looking for.

Later.


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## smokingjoe (Nov 5, 2009)

Pushing it through is better for the fan, unless it's very heat tolerant.


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## MarihuanatrÃ¤umt (Nov 5, 2009)

I run 2 600's and have a 435cfm fan that in the middle of the lights.  Meaning light fan light and it works for me


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## dman1234 (Nov 5, 2009)

pull is best imo
fan runs more effiecently


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## GroHi (Nov 5, 2009)

Just a thought air pressures & leaks throughout the line...  When you tie a fan into a duct line, everything before the fan is under negative air pressure.  The fan is sucking the air in which causes a lower air pressure within the ducting.  On the other side of the fan, air is being forced out & creates a greater air pressure within that portion of the ducting.    The effect is that all the connections/leaks/tears/rips in the ducting before the fan will be sucking air into the line.  On the back end of the fan, the air within the line will try to escape out of the leaks.  I've found this to be an issue w trying to scrub your exhaust air fully... if venting out to the attic, or whatnot, & you use a fan on the back-end of the line, it will be sucking in unscrubbed air then venting out for all to smell.  Here's a pic that will hopefully help in what I'm concerned about...    Granted the fan works harder, but easily dealt w by just going bigger on the front side.  peace everyone.


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## Budders Keeper (Nov 5, 2009)

I think I do it similar to GroHi but for different reasons.  I have fan pulling everything from room and pushing through filter(filter outside room-fan inside). This is not the most efficient but I went a little overkill on the fan to make up for it. 

The reason I did it this way is the filter muffles the noise making it virtually silent...which was a concern for me considering you used to hear fan blowing when standing in my driveway near garage.


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## captain1 (Nov 5, 2009)

For me pulling is the most efficient drops my room temp by 6 degress. I have tried it both ways.  Mine goes carbon scrubber to light to fan and out my attic vents.


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## smokingjoe (Nov 5, 2009)

Pulling through a carbon filter is ideal, but unless your fans are high temperature rated with quality Japanese bearings; push cool air through the cool tube and exhaust.  It will extend the life of the fan and reduce fire risk.


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## astrobud (Nov 6, 2009)

thanks friends i see were about half and half on this.


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## monkeybusiness (Nov 6, 2009)

The reason i decided against pushing air was that it pressurizes the tube (as stated before) and if there are any leaks, it can push hot air back into the grow room. Kind of defeats the purpose.
 Good luck with whatever u decide and lets us know how it goes!


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## GroHi (Nov 6, 2009)

Check out those stretch wrap rolls you can get at WMart, or most packaging places...  It rolls real nice to make a solid, air-tight wrap.  Packaging tape to close off the ends.  Great stuff, no matter how you're running the fans...  Peace!


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