170 cfm okay for Air/Cooled 400 wtt HPS?

WeSmkDro

Well-Known Member
Carbon filter > Duct > A/C 400 watt > Duct > 170 CFM Fan > Duct into attic.

is this okay?

i just got the fan ... even if its not okay im going to have to make due ... im just hoping it is ... holla. :o
 

WeSmkDro

Well-Known Member
I'd like to know too, where'd you get the fan from? I got mine from home depot.

damn nobody will answer us : x! i got mine from HTG , i looked at lowes and couldnt find any inline fans ... im in shock that they even have the things! lol. lets hope someone answers.
 

Juan Valdez

Active Member
it should be fine as long as your ambient temps aren't too high. keep your house around 70 degrees and your good, if your house gets up to 75-80 + degrees then you have a problem. general rule of thumb is, your light (even air-cooled) will add about 10 degrees in the grow room onto the temp of your house.
 

g00sEgg

Well-Known Member
lol...well i'm gonna make it work either way...but i'm not pulling mine through a scrubber...so i should be fine i think.
 

WeSmkDro

Well-Known Member
lol...well i'm gonna make it work either way...but i'm not pulling mine through a scrubber...so i should be fine i think.
eek , yeah. i wonder how much cfm that scrubber knocks off : / . calculations for the room say i only need 66 cfm to clear the room every 3 minutes... so i have 100 more than i really need ... but the ducts scrubber and air cooled hood ... i wonder if i still come out positive ... i guess thats what this thread is for.
 

MyGTO2007

Well-Known Member
Carbon filter > Duct > A/C 400 watt > Duct > 170 CFM Fan > Duct into attic

if everything is in a straight perfect line
otherwise no!!!!
first of all after you go threw the filter then ducting the light more ducting that fan will be less than half its cfm's (@170)

plus you want to blow threw the lights, so fan isnt sucking hot air threw fan and making it hot!
it all depends on how much duct work and how many bends
i would start with atleast 400cfm
how big is yer room
 

WeSmkDro

Well-Known Member
Carbon filter > Duct > A/C 400 watt > Duct > 170 CFM Fan > Duct into attic

if everything is in a straight perfect line
otherwise no!!!!
first of all after you go threw the filter then ducting the light more ducting that fan will be less than half its cfm's (@170)

plus you want to blow threw the lights, so fan isnt sucking hot air threw fan and making it hot!
it all depends on how much duct work and how many bends
i would start with atleast 400cfm
how big is yer room
wow damnit to hell ... even less than half the cfm is still more than sufficient to vent the room in 3 minutes. but wow ... now i need to figure out how to keep these ducts in a straight line , thanks for giving me some mind candy. if ANYONE else has any opinions on this subject, i would really like to hear what you have to say, sometimes people have seperate ideas about these kinds of things : / .
 

mochadog70

Active Member
Carbon filter > Duct > A/C 400 watt > Duct > 170 CFM Fan > Duct into attic

if everything is in a straight perfect line
otherwise no!!!!
first of all after you go threw the filter then ducting the light more ducting that fan will be less than half its cfm's (@170)

plus you want to blow threw the lights, so fan isnt sucking hot air threw fan and making it hot!
it all depends on how much duct work and how many bends
i would start with atleast 400cfm
how big is yer room
Yes what he said you need a bigger fan like I said before and a lot of company's like to lie about their ratings so that POS could maybe do 17- cfm if the wind was blowing at 50 mph with no ducting. Save some $$ because it'll pay you back so quick.
 

TheBoozer

Member
Yes what he said you need a bigger fan like I said before and a lot of company's like to lie about their ratings so that POS could maybe do 17- cfm if the wind was blowing at 50 mph with no ducting. Save some $$ because it'll pay you back so quick.
I am currently doing a closet grow with a 400w mh in an econo wing reflector. Even with the closet doors closed the temps don't get over 80. I leave the doors open now just to keep it safe and I have a 4" 140 cfm fan pulling air from the closet to the attic. The vent is sitting about 2 feet over the reflector and everything seems to be just fine. I think you'll be alright.

I would not run a carbon filter on the current fan and hope it would cool things down as well. If you want to run a scrubber and vent the room you should get a seperate fan for venting and one for scrubbing.

Just out of curiosity how much did the fan run you.
 

MyGTO2007

Well-Known Member
I got a 300cfm running a 600w cooltube but about 4 ft of duct check it out!:bigjoint:
[youtube]X13ukaOIH-o[/youtube]
 

MyGTO2007

Well-Known Member
I am currently doing a closet grow with a 400w mh in an econo wing reflector. Even with the closet doors closed the temps don't get over 80. I leave the doors open now just to keep it safe and I have a 4" 140 cfm fan pulling air from the closet to the attic. The vent is sitting about 2 feet over the reflector and everything seems to be just fine. I think you'll be alright.

I would not run a carbon filter on the current fan and hope it would cool things down as well. If you want to run a scrubber and vent the room you should get a seperate fan for venting and one for scrubbing.

Just out of curiosity how much did the fan run you.
But yeah Thats Your Room...everyones setup is different :bigjoint:
 

WeSmkDro

Well-Known Member
wow ... damn you for having your shit together ... lol. : ( . looks really good , i like how you have all those strains growin ... your where i want to be ... a place where my budget cant take me. im now stuck with this 170 cfm ... and i have to make the best of it ... damnit ... damnit to hell.
 

Juan Valdez

Active Member
you should be fine, a 400w in a 5x5 ft closet isn't gonna create crazy rediculous amount of heat. as long as the place you live in doesn't get too much over 70 you shouldn't have too hard a time keeping it reasonably cool with the equipment you have, especially since your venting to your attic were the heat will escape.

run the lights at night too when its cooler outside, like 7 pm lights on - 7am lights off, it will help!

and put an ocsillating fan in there to move air around, that'll help keep things cool also
 

Punk

Well-Known Member
Did you buy the tin inline fan with the plastic blades or did you buy an actual centrefuge fan? Because if you bought the $30 fan, it's not a true 170 cfm. Those fans will not lower temps even 1 degree and they jam up.
 

WeSmkDro

Well-Known Member
Did you buy the tin inline fan with the plastic blades or did you buy an actual centrefuge fan? Because if you bought the $30 fan, it's not a true 170 cfm. Those fans will not lower temps even 1 degree and they jam up.
okay i bought a REAL inline fan ... shit isnt going to break. it was a combo deal from HTG SUPPLY , i dont go too cheap ... just didnt know i needed a bigger size.
 

stinkbudd1

Well-Known Member
Hey all, i hate to rain on everyones parade but i just learned a very valuable lesson.. For the last year ive been fighting high temps in my grow box, 5x3x2 w/250 hps, 12" & 6" circulating fans 12" blowing on light,(3) 4" inline fans yes the cheap shit from home depot 80 cfm's maybe, passive and forced air intake w/ (1) 80 cfm fan and one 4 1/2 " hole my temps were at 86 constantly and reached 90 often... now i know you hydro shop guru's are out there soliving cant wait to tell me to run out and get some high priced vortex fan or a.c unit etc etc.Well i didnt, i instead did more reading on negative pressures and exaust as well as some thing called air volume in refference to space and exausting that air.. What i found is that i was, simply put, putting to much air into my grow cab. But, not by way of intakes passive or force, yet by running both of those circulating fans on medium to high trying to cool the light, i really was only moving the hot air around the cab (circulating) with to much air..Ok so here is what i did first i made sure to even out the intake and exaust with my intake only slightly less cfm's as my exaust, 160 exaust... 80 cfm forced and 3 1/2 "passive intake to get a good negative on my return of fresh air..but the main thing that i did was get rid of the extra air i was pushing by removing the 12" oscilating fan completely from my room,leaving only the 6" to circulate under the plants, i also only use two of the 4"fans for exaust and cooling now i removed the one from the hps my temps now are at a constant 76 degrees and i feel good ...so to make a long story short two things to do get the right ratio intake to exaust but mainly dont create more air in your grow room by way of oscilating fans then your exaust can handle..peace
 

purplecream

Active Member
^^ why even use an intake fan? doesnt the exhaust fan create enough negative pressure to just leave a little hole in the bottom or in a tent leave a flap open. then you can add your oscillating fan between your light and plants to get them a little bit closer. or am i wrong?
 
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