Push or pull air?

[Farmer Stealth]

I'm currently using a 600w mh/hps light in my grow room (currently only using a 4'x5' area), and my set up is currently, filter > light > 6"exh fan > out to attic.
I'm looking at adding a second 600w light, (making my grow area 4'x9'), and I'm worrying about my exh fan. I've heard that you can damage or burn up an exhaust fan and that you should push the air through the lights.
If I do add the second light I'm gonna put my filter on a seperate 4" exh fan and I'd draw fresh air for the lights from a seperate room.
So should I go with this,
vent > light > light > exh fan > out to attic,
or,
vent > exh fan > light > light > out to attic.

Any thoughts or guidance would be greatly appreciated.

 

[djstiks]

thats what she said....

 

[slave4sail]

Either will work fine as long the fan is a decent quality manufactured inline fan. They are built to work in higher heat environments for long periods of time. Unless I misread your posting, it appears you are only going to run a carbon filter on the newly ducted 4" exhaust run? I assume only exhausting the room with this? I urge a carbon filter on intake or at the end of the run in the attic also, the 6" run that is exhausting your lamps.

Unless you can be 110% certain the duct run is airtight, and the larger 6" fan does not interrupt the flow pattern of the new 4" fan; please consider carbon filters for both duct runs.

Even though the intake is from a different area, a 6" fan is much more powerful than a 4" fan. Not saying that this will be the case all of the time, but the 6" intake side that is not filtered may end up borrowing some stinky air that the 4" fan just can not keep up with.

It will depend on other variables, but do some sort of smell test beforehand if at all possible. Carbon filters are not extremely costly, and can even be DIY if you are handy.

But again to confirm your worries, the fan will not burn up if you put it after the lamps versus before them. Either situation will work, and have advantages over the other. You mention the access to an attic for exhaust, you can even put the fan inside the attic. It all depends on what you prefer at that point, and would be splitting hairs. Bottom line, so long as the fan is a reputable manufacturer it is built for exposure hot and abusive environments for long periods of time.

1.2kw of lamp heat should be a piece of cake for any 6" worth their salt. hope you find help in my comment. look into another carbon filter, or at least consider it.

 

[Farmer Stealth]

Thanks Slave.
Both fans, the 6" and the 4", are Grow Bright exh fans bought from HTG. Haven't had any problems yet. And the filter is a carbon filter.
My grow room is a walk in 5'x9' closet off my master bathroom, I was gonna cut a hole in the wall between the two rooms, I found a nice lookin' vent cover that I was gonna put on the bathroom side then use a ducting sleeve to the attach to the system. I've got the whole room sealed, all joints, (hehe), are caulked up so there ain't any leaks.
Got another question for "the experts".
Is there a controler for a filter fan that will, one, run a fan at a preset time, say like 15min every hour, AND, turn fan on if temps reach a certen temp, say like 90deg plus. Just wonderin' cuz I'm thinkin' bout mabey adding Co2 to my garden in another grow or two.
Agian, thanks y'all.

 

[overbudjet]

If you want to add co2 later i will say grip a growtronix system
it will control everything co2 included for around 1100 box it is a complet growroom control.You can control fan/co2/light/dehu,everything you want with your computer.you can even set alarm(email to your cell phone) if certain condition are reached