ProBudster

Hi I have a small cabinet 2,5 x 2,5 feet and 250w hps with a good extraction fan which goes on and off every 15minutes but no intake fan, just holes and another fan circulating air inside constantly and when the cabinet is closed the temps rise to 100 degrees farenheit during the fan off time of 15min then when the fan is on 90-95 degrees. I have the fan off time just to let it cool down cause it is a refrigerator fan and Im not sure how long you can leave them on without blowing, What is the best solution to keeping the temps low inside the cabinet? I also want to make a carbon scrubber to control odor on the extraction but if I leave the door open to keep temps low the carbon scrubber might not work effectively

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Futuregrower

put 250 W inside a DIY cool tube, hooked up to your extraction fan. Leave the extraction on at least for lights on.

If you are turning the fan off to let the fan cool down, why? does your fan overheat? if so, something is badly wrong.

If you do it just so the fan doesn't add to the heat via the motor, it should be fine. If not, put the fan outside or get a different one.

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Jgreenleaf

from the sounds of it yo hav a passive intake... waht size holes do you have for that?... for sure use a cool tube on that hps

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ProBudster

There are four holes 2"x2" for the intake but now Im trying leaving the fan on during the lights on time, and on and off every 30min during lights out. The temps have dropped to 93 fahrenheit during lights on.

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ceyx

add some more passive intakes to the cab. i can't say for sure what size you need without knowing a few other factors, but generally 16" sq is probably going to be a bottleneck, esp. when it's four 2x2 holes.

recommended reading:
https://www.gardenscure.com/420/cons...d-madness.html
(good info on CFM requirements, make sure your fan is up to the job)

there's another thread around, can't find it, but if i recall correctly the general idea was that you need at least 3-4 times the area in intake vs. exhaust.

this doesn't mean 12 to 16 in^2 for a 4" exhaust; a 4" exhaust is 12.56 inches of area... just a thought.

hope that helps!