yankee7568
New Member
I tell you what, I have no idea what the heck to do.... I put a 100CFM fan to pull air up through the carbon and its still has high temps.....
Wood selection for enclosure
- Thread starter Lil Neutrino
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- #22
Lil Neutrino
New Member
Ok, excuse me if I am confused...been drinking for a while 
If I understood your explanation on the first page completely you are sucking in fresh air from the rear of the cabinet in the "middle" chamber, correct? I.E. through that little black spot that can barely be seen in the second pic.
Actually, let me step back a bit...are you using the 100CFM fan for an exhaust? I'm assuming you are but you never explicitly said so, or maybe you did and I'm too inebriated to see it (sorry). If so how large is the cutout for that 100CFM and how large are the intakes? What I'm trying to figure out is if you are restricting the air flow in to the cabinet or not...I'm gonna come back to this tomorrow when I'm sober. I don't mean to ask any repetitive questions but it happens
A 100CFM exhaust fan in a cabinet that size should be plenty large. One other question...what is the temperature difference between ambient and your intake? Also how much carbon do you have in your scrubber, it is possible that if you have "too much" that you can restrict airflow out of the exhaust and reduce the air flow rate.
I'll stop now before I babble on too much...catch you in the morning/early afternoon.
If I understood your explanation on the first page completely you are sucking in fresh air from the rear of the cabinet in the "middle" chamber, correct? I.E. through that little black spot that can barely be seen in the second pic.Actually, let me step back a bit...are you using the 100CFM fan for an exhaust? I'm assuming you are but you never explicitly said so, or maybe you did and I'm too inebriated to see it (sorry). If so how large is the cutout for that 100CFM and how large are the intakes? What I'm trying to figure out is if you are restricting the air flow in to the cabinet or not...I'm gonna come back to this tomorrow when I'm sober. I don't mean to ask any repetitive questions but it happens
A 100CFM exhaust fan in a cabinet that size should be plenty large. One other question...what is the temperature difference between ambient and your intake? Also how much carbon do you have in your scrubber, it is possible that if you have "too much" that you can restrict airflow out of the exhaust and reduce the air flow rate.
I'll stop now before I babble on too much...catch you in the morning/early afternoon.
yankee7568
New Member
Ok, excuse me if I am confused...been drinking for a while
Actually, let me step back a bit...are you using the 100CFM fan for an exhaust? I'm assuming you are but you never explicitly said so, or maybe you did and I'm too inebriated to see it (sorry). If so how large is the cutout for that 100CFM and how large are the intakes? What I'm trying to figure out is if you are restricting the air flow in to the cabinet or not...I'm gonna come back to this tomorrow when I'm sober. I don't mean to ask any repetitive questions but it happens
A 100CFM exhaust fan in a cabinet that size should be plenty large. One other question...what is the temperature difference between ambient and your intake? Also how much carbon do you have in your scrubber, it is possible that if you have "too much" that you can restrict airflow out of the exhaust and reduce the air flow rate.
I'll stop now before I babble on too much...catch you in the morning/early afternoon.
Ok, The middle chamber is no longer the tin tube its a square card board rectangle that I fabed up cause the 100CFM fan is over 4". So I had to make a bigger tube so to speak. There is not much carbon at all in the rectangle chamber I fab up. The middle chamber is the exhaust and it has the 100CFM fan in it. The cut out for the 100CFM fan is big enough to blow the air out. The intake is just a hole to the left of the lights, the black thing. There is no fan in it and its a 3.5" hole. The temps outside the box is 70-77 degrees. The temps inside the box is over 100 degrees.. I think my plants are now showing signs to heat stress... But they are growing.. I will get pics of the whole set up.
yankee7568
New Member
Ok here are the pics.
New carbon filter
here is the 100 CFM fan inside the filter
top veiw
with the carbon filter under it
intake cover
I put a 120mm fan in the intake port to see what it would do and it is still high!! I don't know the CFM of that fan though.
New carbon filter
here is the 100 CFM fan inside the filter
top veiw
with the carbon filter under it
intake cover
I put a 120mm fan in the intake port to see what it would do and it is still high!! I don't know the CFM of that fan though.
- Thread starter
- #25
Lil Neutrino
New Member
Ok, I think I have your enclosure figured out but to be sure I drew it up in paint...let me know if I have anything wrong.
What brand/model fan is that that you are using? 100CFM is not unheard of with PC fans but not too common either in my experience so I'm curious
Also, one thing I see that could be causing you some airflow problems is your intake. If I'm understanding how you have it rigged up correctly from the pictures your light trap may be causing you issues. You stated it is a 3.5" hole which is a hair on the small side since your exhaust is now a 4" hole...you want them at least equal or better yet have the intake a little larger to create that negative pressure inside your grow space. It will also allow your exhaust fan to work a little easier.
However, the design issue that I'm really noticing is the small area that you left for the air to get in to the enclosure from the light trap. I can't tell if it is open on the bottom and the left side or on just one side. It also looks like you have maybe 2" of clearance to the left and maybe about an inch on the bottom (assuming both sides allow air to flow in). Ideally when you are bringing air in or out of something you want to have the same distance of obstruction clearance as the size of the "port". Take your 4" exhaust for example, you would want to have 4" of unobstructed clearance above it to ensure proper air flow. You can get away with a little less but ideally it is equal. So, the way that intake light trap is designed it could be causing poor air flow...any chance you can take it off and see if your temps drop at all?
A 20F+ temperature rise is very very high and I can understand why your plants are starting to show heat stress. Also, is that a CO2 system you are running? If so that will help the plants "breath" with higher temps up to the mid-80's/90ish range (if I read correctly) but you still have to deal with the physical temperature that the leaves must contend with as you know. I may have missed it, how many/what size lights do you have in there and what are the dimensions of the grow chamber (what I'm calling the middle chamber)? Also, where are you measuring your temperature at?
What brand/model fan is that that you are using? 100CFM is not unheard of with PC fans but not too common either in my experience so I'm curious
Also, one thing I see that could be causing you some airflow problems is your intake. If I'm understanding how you have it rigged up correctly from the pictures your light trap may be causing you issues. You stated it is a 3.5" hole which is a hair on the small side since your exhaust is now a 4" hole...you want them at least equal or better yet have the intake a little larger to create that negative pressure inside your grow space. It will also allow your exhaust fan to work a little easier.
However, the design issue that I'm really noticing is the small area that you left for the air to get in to the enclosure from the light trap. I can't tell if it is open on the bottom and the left side or on just one side. It also looks like you have maybe 2" of clearance to the left and maybe about an inch on the bottom (assuming both sides allow air to flow in). Ideally when you are bringing air in or out of something you want to have the same distance of obstruction clearance as the size of the "port". Take your 4" exhaust for example, you would want to have 4" of unobstructed clearance above it to ensure proper air flow. You can get away with a little less but ideally it is equal. So, the way that intake light trap is designed it could be causing poor air flow...any chance you can take it off and see if your temps drop at all?
A 20F+ temperature rise is very very high and I can understand why your plants are starting to show heat stress. Also, is that a CO2 system you are running? If so that will help the plants "breath" with higher temps up to the mid-80's/90ish range (if I read correctly) but you still have to deal with the physical temperature that the leaves must contend with as you know. I may have missed it, how many/what size lights do you have in there and what are the dimensions of the grow chamber (what I'm calling the middle chamber)? Also, where are you measuring your temperature at?
yankee7568
New Member
Ok, I think I have your enclosure figured out but to be sure I drew it up in paint...let me know if I have anything wrong.
What brand/model fan is that that you are using? 100CFM is not unheard of with PC fans but not too common either in my experience so I'm curious
Also, one thing I see that could be causing you some airflow problems is your intake. If I'm understanding how you have it rigged up correctly from the pictures your light trap may be causing you issues. You stated it is a 3.5" hole which is a hair on the small side since your exhaust is now a 4" hole...you want them at least equal or better yet have the intake a little larger to create that negative pressure inside your grow space. It will also allow your exhaust fan to work a little easier.
However, the design issue that I'm really noticing is the small area that you left for the air to get in to the enclosure from the light trap. I can't tell if it is open on the bottom and the left side or on just one side. It also looks like you have maybe 2" of clearance to the left and maybe about an inch on the bottom (assuming both sides allow air to flow in). Ideally when you are bringing air in or out of something you want to have the same distance of obstruction clearance as the size of the "port". Take your 4" exhaust for example, you would want to have 4" of unobstructed clearance above it to ensure proper air flow. You can get away with a little less but ideally it is equal. So, the way that intake light trap is designed it could be causing poor air flow...any chance you can take it off and see if your temps drop at all?
A 20F+ temperature rise is very very high and I can understand why your plants are starting to show heat stress. Also, is that a CO2 system you are running? If so that will help the plants "breath" with higher temps up to the mid-80's/90ish range (if I read correctly) but you still have to deal with the physical temperature that the leaves must contend with as you know. I may have missed it, how many/what size lights do you have in there and what are the dimensions of the grow chamber (what I'm calling the middle chamber)? Also, where are you measuring your temperature at?
Seems you have my box drew up fine. This is the fan I am using 4" Flat Whisper Fan - 100CFM Growbox Cooling Fan - eBay (item 260419308773 end time Jun-25-09 07:56:41 PDT)
As, for the light trap, its about an inch front the bottom. So I will take it off and see what it will do, once the lights are on. Last night I added another intake fan that is 3.5" and it dropped the temps down to 95f.... So, we are getting there. Thats with the light trap on the other fan also.. Yes, that is CO2 I am running. Its the yeast, sugar and water method. As for lights I am using 3 CFL 42w (150w) 2900 lumens (there hot to the touch when on) soft white and one 26w (100w) 1600 lumens bright white (thats not hot to the touch when on). I am measuring my temperature from a wireless temp gauge from Homedepot. It has the base part that goes inside the house and a wireless box for out side to get that temp. I have the the wireless box inside my grow chamber and the base outside in my room. The wireless box is at the top of the chamber. You can see it in some of my pics
Its to the left and at the top, white in color. As for the dimensions 28 3/8 wide 19 3/4 deep 23 even tall.
Thanks a lot for your help.
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- #27
Lil Neutrino
New Member
I can hold my 26W CFL's too...haven't messed with the 42W ones yet but I can imagine they would be a bit hot.
I tried to find a technical spec page for that fan but have had no luck. It's made in China and seems to be easily found at wholesale importers. I would be a bit skeptical of the 100CFM rating but it should still be enough to turn over the air in your chamber at a decent rate as your grow chamber is just shy of 8ft^3.
If adding another intake fan lowered your temps a noticeable amount then I think you'll see even better results when you give the intake more room to allow air to flow in to the grow chamber Keep me posted!
I tried to find a technical spec page for that fan but have had no luck. It's made in China and seems to be easily found at wholesale importers. I would be a bit skeptical of the 100CFM rating but it should still be enough to turn over the air in your chamber at a decent rate as your grow chamber is just shy of 8ft^3.
If adding another intake fan lowered your temps a noticeable amount then I think you'll see even better results when you give the intake more room to allow air to flow in to the grow chamber
Keep me posted!yankee7568
New Member
Ok man I will try it out. I might put another intake fan in also, t have a total of 3 fans. Thanks for your help
yankee7568
New Member
ok I removed the light trap and it didn't do anything. So, I added another intake fan (total of 3) and it dropped the temps down to 91f..... So, from 110f, I would say thats pretty good. I am thinking of just buying 8 26w CFL and use those instead cuase they wont produce this much heat... What you think?
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- #30
Lil Neutrino
New Member
Try it and see, you can always return them if you don't mess up the packaging. From 110 to 91 is a pretty good drop. The 26W CFL's can produce some heat in small spaces especially when you get quite a few of them. With 10 of them in my cabinet I was seeing temps of over 90F a few times, even 99.5 one morning!
yankee7568
New Member
Turns out it wasn't heat stress it was bugs, but Idid get the temps down by removing one of the 150w bulbs... Thanks for your help..
- Thread starter
- #32
Lil Neutrino
New Member
You're welcome...keep us updated
yankee7568
New Member
Check out my journal.
