Exhaust fan on 24/7??

shenagen

Well-Known Member
I was just wondering if my exhaust fan should run all night, and my
ocilating(?) one too. Would there be a difference between the veg room and flower room, or is the advice the same?

Also...how long should my exhaust fan be off during a co2 cycle?
:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
 

email468

Well-Known Member
i leave all my fans on 24x7 (except the one that air-cools my light - that is a "lights-on" fan) - but i am not using supplemental CO2.
 

shenagen

Well-Known Member
Thats what I thought...leave em on. So then, the other part...how long should I leave off my exhaust fan during co2 cycles?
 

McLovin420

Well-Known Member
Dude I use co2 so I don't vent out my air, maybe I'm wrong here but it hasn't affected them yet. If your going to vent it out I've heard every 3 hours or run it just before your co2 cycle.
 

shenagen

Well-Known Member
My rooms are completely sealed though...the doors, the sides, floors..everything. Before I put my intake vents I did a test to make sure everything worked. You could turn on the exhaust fans and they would suck the floors up into a bubble there was so much negative pressure. it almost sucked the walls off too, but I turned the fans off as soon as I noticed.
 

girlyhits

Well-Known Member
If your using co2 during your lights off period I wouldn't run the exhaust fan because it would simply be drawing the co2 out of the room. I would however run an regular fan to help circulate the co2 within the room.
 

shenagen

Well-Known Member
I'm talking about when the lights are on...how long should I turn the exhaust fan off during a co2 cycle
 

McLovin420

Well-Known Member
is it on a time schedule or is on a ppm meter? if it's on a time schedule have your exhaust fan come on, run long enough to clear out the old air, then shut off just before your co2 cycle starts. if it's on a ppm meter I have no idea.

i don't think you have to vent if it's completely sealed thats what the co2 is for. if you don't have co2 you need to bring in fresh air so the plants can get co2. again i could be wrong but if i remember correctly on a urban grow video thats what he says & it makes sense to me
 

shenagen

Well-Known Member
is it on a time schedule or is on a ppm meter? if it's on a time schedule have your exhaust fan come on, run long enough to clear out the old air, then shut off just before your co2 cycle starts. if it's on a ppm meter I have no idea.

i don't think you have to vent if it's completely sealed thats what the co2 is for. if you don't have co2 you need to bring in fresh air so the plants can get co2. again i could be wrong but if i remember correctly on a urban grow video thats what he says & it makes sense to me

No I'll have to vent to keep the temp and humidity down. The room is sealed except for the exhaust output and an intake in each of the rooms. This is a homebuilt super closet type of thing...so the rooms weren't big enough to completely seal and run an AC/heat and such. I wanted them to be sealed so there would be negative pressure when the exhaust fans came on and air gets sucked in through the intake vents.

And yeah the co2 will be timer controled...not to keen on buying a 100 dollar meter to read the ppm. Since it takes 9 min. for the room to fill up with co2 the fan will obviously be off that long, but I need to know how long until I should have the exhaust come on. I may have to make another thread since the title of this one is misleading.
 

ste147

Well-Known Member
how do i keep my room heated to over 70 degrees during the lights off period? im running my exhaust fan 24/7, as temps outside at night can be really low and the plants are going yellow being in cool air spots and drafts, i have a convection heater in the room but its only keeping the plants warm directly infront of it, having a nightmare!!!!
 

hunter22375

Well-Known Member
I'm talking about when the lights are on...how long should I turn the exhaust fan off during a co2 cycle
I just re-read the thread. I think it depends on how long it takes the room to get too hot during the lights on cycle. You could set it based on that.
 

k3nz1387

Well-Known Member
run both fans during light off with no co2...
at lights on turn off extractor then run co2 for approx 10 mins or to desired co2 levels..
use co2 every 3 hours but run extractor 15-30 minutes before..

just keep looking at temps at canopy level and humidity..the plantscan handle temps a lil higher while using co2..up to around 90f but no higher
ideal temp is 85f when using co2.
 
I was just wondering if my exhaust fan should run all night, and my
ocilating(?) one too. Would there be a difference between the veg room and flower room, or is the advice the same?

Also...how long should my exhaust fan be off during a co2 cycle?
:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
Ideally you want to keep your night time temps the same as your day time, maybe even a little warmer. Having your exhaust on 24/7 during night hours will help maintain that 50% humidity level. During day hours your your exhaust should NOT be on 24/7, especially if you are using co2. The exhaust is just going to be sucking the co2 right out of the room, wasting co2 and in turn defeating the purpose of even having co2 in the first place, and possibly making it too hot in there because your burner is constantly on.
 
Also, don't bother running co2 at night time. They don't consume anything, through roots or leaves while they are asleep. Pick yourself up a cyclestat http://jonsplantfactory.com/products/day-night-periodic-cycle-timer/ and dial it down to the minute when you want your exhasust to turn on, and then off.

ste147, get yourself a better heater and set it on a timer to turn on when your lights turn off, to maintain day time heat at night time hours.

shenagen, buy a burner and plug it into a co2 computer. the computer tells the burner when to kick on if the co2 ppm's drop below your desired amount. Set your exhaust to come on every 20 minutes or half hour but only run it for 1 or 2 minutes (depending on your fan size) so that the room is getting a new load of fresh air twice or three times every hour, but keeping co2 waste to a minimum
 

ste147

Well-Known Member
I just re-read the thread. I think it depends on how long it takes the room to get too hot during the lights on cycle. You could set it based on that.
run both fans during light off with no co2...
at lights on turn off extractor then run co2 for approx 10 mins or to desired co2 levels..
use co2 every 3 hours but run extractor 15-30 minutes before..

just keep looking at temps at canopy level and humidity..the plantscan handle temps a lil higher while using co2..up to around 90f but no higher
ideal temp is 85f when using co2.
Ideally you want to keep your night time temps the same as your day time, maybe even a little warmer. Having your exhaust on 24/7 during night hours will help maintain that 50% humidity level. During day hours your your exhaust should NOT be on 24/7, especially if you are using co2. The exhaust is just going to be sucking the co2 right out of the room, wasting co2 and in turn defeating the purpose of even having co2 in the first place, and possibly making it too hot in there because your burner is constantly on.
Also, don't bother running co2 at night time. They don't consume anything, through roots or leaves while they are asleep. Pick yourself up a cyclestat http://jonsplantfactory.com/products/day-night-periodic-cycle-timer/ and dial it down to the minute when you want your exhasust to turn on, and then off.

ste147, get yourself a better heater and set it on a timer to turn on when your lights turn off, to maintain day time heat at night time hours.

shenagen, buy a burner and plug it into a co2 computer. the computer tells the burner when to kick on if the co2 ppm's drop below your desired amount. Set your exhaust to come on every 20 minutes or half hour but only run it for 1 or 2 minutes (depending on your fan size) so that the room is getting a new load of fresh air twice or three times every hour, but keeping co2 waste to a minimum
THIS POST IS OVER 4 YEARS OLD, I WAS DOING A BIT OF SEARCHING ON GOOGLE, ITS ONLY MY QUESTION THAT NEEDS ANSWERING!!!!!! LOL.....

Sooooooooooo Anythin????? :-)
 
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