Cab Grow fan cycle problems

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munch box

Well-Known Member
Here are my temps as follows:
these temps. are directly below the light (hottest point)
Hour 1 /Start light cycle/68f
5 min in/ exhaust fan off/ 75f
10 min in/ehaust fan off/ 82f
25 min in/ still off/87f
40 min in/still off/92f
50 min in/ exhaust fan kicks on/94.5F
Also- when the fan kicks on the temp. above the light is 87f
5 min in/exhaust fan on/87f
10 min in/ exhaust fan shuts off/80f
Also- when the exhaust fan shuts off the temp. above the light is 82f
These are the test results i've come up with (when leaving my intake fan on 12/12 with the lights). When I don't keep the intake fan on and only use it with my exhaust fan cycle, then my cycles become much, much closer together, with fast temp. swings. The exhaust fan would run 5 times as often, thus eliminating co2 possabilities
 
daddychrisg

daddychrisg

Well-Known Member
Great break down of temps.
5 min in/ exhaust fan off/ 75f
I think this is where I loose you....When you say Exhaust fan.. Are you not talking about your reflectors air supply..You are speaking of a separate exhaust, correct...
 
daddychrisg

daddychrisg

Well-Known Member
I just wanted to make that totaly clear..and get on the same page with you..
Ok, man, like I said before, you have three choices in my mind...Actually 4, you can use dry ice to provide co2 and help keep the temps down...Other then all that I have said, I don't know what else to suggest to you...I really just wanted, and hope I help you figure out some idea's with your problem..I don't have any more idea's at the moment...
 
M

munch box

Well-Known Member
I think these temps will do fine in optimum co2 levels. When people think of co2, the first thing that comes to mind is bigger, faster buds. Often times overlooking other benefits that co2 brings to the table. such as pest control, and able to cope with other stresses such as, high temps., temp swings, low nutrition, and stale air.
 
daddychrisg

daddychrisg

Well-Known Member
I think these temps will do fine in optimum co2 levels. When people think of co2, the first thing that comes to mind is bigger, faster buds. Often times overlooking other benefits that co2 brings to the table. such as pest control, and able to cope with other stresses such as, high temps., temp swings, low nutrition, and stale air.
Yeah, but I would not go over 90deg myself...if anything changes and you get a temp swing....100deg is not to far off...ya know? I liked your idea with the ac, I was going to mention that you should look into picking one up, but I know how it is buying more and more for your grow op..GL
 
M

munch box

Well-Known Member
I own that a/c and i run it in the summer time to cool my cab and my bedroom. Its in my garage right now cuz its december. the reason i shy away from using it is cuz it runs on max 9.2 amp 960 watts electricity! 95F i think will be fine and my controller will not allow it to get any hotter, thats its job. If 95 turns out to be too hot, and you may be right, At the first sign of heat stress i will dial my controls down a smidge and see what happens. I still don't have my clones should have been here by now.:cry:
 
M

munch box

Well-Known Member
Thanks man, the clones on the way are called Urkle. supposed to be a really good purple but I can't find it. Tried looking it up to find out more and nothing
 
M

munch box

Well-Known Member
F

fdd2blk

Well-Known Member
i just skimmed this thread. not sure where your at now but if your still ballooning your room with your intake you should fix that. i don't think you really need an intake. i only use an exhaust. it's hooked to my hood. air is sucked out of the room, past the light and out the exhaust. it's big enough that is draws negative pressure when the door is closed. i'm pretty sure you want suction. you want the exhaust to pull air in. then have your CO2 and your exhaust timed. when the CO2 comes on the exhaust goes off. vent it into your room. leave your window cracked and you will be fine. i assume. don't suffercate. i have a kerosene heater that burns for 12 hours in my room and it hasn't killed me yet.
 
M

munch box

Well-Known Member
That scenario there sounds like a dream come true fdd2blk, unfortunately I can't leave my fan off for any longer than 12 mins. max without the temp going out of control. UNLESS I leave my intake fan on during the light cycle. I know this sounds wierd but just listen and tell me if it makes sense 2 you or not. When I leave my intake fan on during the light cyle the door expands like a baloon letting co2 seep out through the zipper cracks and any other small hole air can find. Doing that will allow me to keep co2 in my grow cab for 50 mins instead of 10-12 mins. Or at least most of it. Then after 50 mins. the controller turns on my exhaust fan, then thats when the reverse suction that you are talking about begins to happen. and everything cools down for another 50 mins.
 
daddychrisg

daddychrisg

Well-Known Member
The only way that that makes sense to me is, that the air that is coming through your intake is colder then the air you drawing from your exhaust, and there is enough gaps in your box to let the intake air escape.
 
F

fdd2blk

Well-Known Member
munch box said:
That scenario there sounds like a dream come true fdd2blk, unfortunately I can't leave my fan off for any longer than 12 mins. max without the temp going out of control. UNLESS I leave my intake fan on during the light cycle. I know this sounds wierd but just listen and tell me if it makes sense 2 you or not. When I leave my intake fan on during the light cyle the door expands like a baloon letting co2 seep out through the zipper cracks and any other small hole air can find. Doing that will allow me to keep co2 in my grow cab for 50 mins instead of 10-12 mins. Or at least most of it. Then after 50 mins. the controller turns on my exhaust fan, then thats when the reverse suction that you are talking about begins to happen. and everything cools down for another 50 mins.
Click to expand...
i've heard the temps can be higher during CO2 use. up into the low 90's. i could be way wrong. i'm having a hard time keeping mine in the mid 70's even with the 600w light and heater running.

as long as things are green and healthy.......:peace:
 
M

munch box

Well-Known Member
The air coming in through the intake is cold and fresh.Much colder than the air going out the exhaust of course. I got done running some tests and it seems as though when i place my ciculation fan directly at my light( instead of oscillating at plant height) seems to be the only way to keep the temp down for 50 mins. When the cirulation fan is set to oscillate the cab only stays cool for just over 30 mins. before it hits the 95f temp mark. I think what is happening by pointing a fan at the glass lens of my hood disapates some of that radiation kinetic heat that you were talking about earlier daddychrisg
 
M

munch box

Well-Known Member
fdd2blk said:
i've heard the temps can be higher during CO2 use. up into the low 90's. i could be way wrong. i'm having a hard time keeping mine in the mid 70's even with the 600w light and heater running.

as long as things are green and healthy.......:peace:
Click to expand...
Yes temps. can get higher in a a co2 concentrated environment. co2 will make plants become very forgiving. Or at least that has been the case in the past for me. But also I've noticed that in high heat, some strains may become lanky with the nodes spread far apart. But then, some sativa plants thrive in temps over 100 degrees!. Ok so here is something else that i just realized, With the intake fan on it will bring fresh air in with the co2, while at the same time removing old stale air from the confined 24 ft cubed grow space.
 
daddychrisg

daddychrisg

Well-Known Member
Ok so here is something else that i just realized, With the intake fan on it will bring fresh air in with the co2, while at the same time removing old stale air from the confined 24 ft cubed grow space.
Are you ok with the MIXED air?
 
M

munch box

Well-Known Member
odors are not going to be a problem. i've already got that base covered. But if your asking about how the mixed air could pressurize and balloon my walls into some type of unstable equilibrium with air moving in scattered directions like a tornado then the answer is - I don't know. That is one of the questions i have been trying to figure out since i first started this thread. The new ULTIMATE QUESTION is - Will an increase of cabin pressure create unsafe grow space for the plant to grow or will it Rock On?:blsmoke:
 
F

fdd2blk

Well-Known Member
munch box said:
odors are not going to be a problem. i've already got that base covered. But if your asking about how the mixed air could pressurize and balloon my walls into some type of unstable equilibrium with air moving in scattered directions like a tornado then the answer is - I don't know. That is one of the questions i have been trying to figure out since i first started this thread. The new ULTIMATE QUESTION is - Will an increase of cabin pressure create unsafe grow space for the plant to grow or will it Rock On?:blsmoke:
Click to expand...

very good question. like i mentioned, i've always heard you want negative pressure. what exactly does positive pressure do/cause. :neutral::confused: hurts my ears.
 
M

munch box

Well-Known Member
I have looked somewhat into this issue before and sticky had only mentioned that running an intake without the exhaust will push pleasant odors through the cracks instead of out the exhaust. The post never mentioned how air-tight of a cab he is refering to though, or any other REAL issues somebody could expect to have. I will need to look into this more. If anybody has some literature. please post me a link -thankyou
 
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