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Thread: HPS heat issues...

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    New Member mohawk's Avatar
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    Question HPS heat issues...

    My partner in crime has run into an issue as of late. His grow box is roughly 3x4x6 and has a 70cfm vent fan running 24/7 and all was fine with cfl bulbs. Crappy yield, but no heat issues. Now with a 400 watt hps in there with no cooling tube or glass shield, its reaches 110 degrees easily, and i hate to say it, but things have really gone to pot in there. Im guessing that the major problem is the vent fan since the ballast is outside the box and therefore not a factor in the heat source. So im figuring that a 265cfm vent fan would be the best answer for his solution. Nothing like a little over-kill, but hey, better more than less right? Also, the box is painted flat white inside and has breather holes on the side for passive fresh air inlets. I was just asking/looking for conformation and or any other ideas as how to handle this problem. Thanks yet again in advance.

    Mohawk

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    Re: HPS heat issues...

    I think I would try a ventilated hood with a good 6" fan. Without co2 you need to keep the temps below 80 or they are going to terrible.

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    New Member Cruzer101's Avatar
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    Re: HPS heat issues...

    I would look into a cool tube or a DIY deal where you make it yourself. I did it with a 400watt in a 36" by 18" by 72" tall cabinet. The light can be up to 8 inches away. I used a 4" duct fan to suck the air through. I think it is rated at 110 cfm.

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    420 Member Smokeyjoe's Avatar
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    Re: HPS heat issues...

    You are on the right track but I think the answer is a combination of both a bigger exhaust fan and somehow making an A/C hood of some kind for the 400w.

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    New Member mohawk's Avatar
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    Re: HPS heat issues...

    Thanks for the tips guys. We are still waiting on the exhaust fan to come in, but i will surely keep this updated, win, lose, or draw. Worse comes to worse, we are gonna air cool the hps by making a home made rig. Good thing about smoking is it makes things seem really complex but attainable to do. Never a dull moment around here

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    Re: HPS heat issues...

    That's why I use LEDs, my cabinet is plastic and would melt if I had HPS and the fan wasn't on for some reason. Not to mention what that would do to the plants.

    I just switched to Haight Solid State LED lights.

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    Re: HPS heat issues...

    hello my freind,going to\ pass on some info i got from southern weed(i have tried,and it works),cheap co2 cannister is 3/4 a bottle of water,in this tip a cup of pure cane sugar,and powdered yeast,shake vigorously,the chemical reaction creates co2,suspend this above your plants,i was run ning close to 42 degrees,went down for some reason dramatically to 30 degrees,fitted a 4" exhaust,now down to 26 degrees,im using a 600 watt as well,might not work,but for the sake of a bottle of water.............whats to loose,keep the faith my freind!!!!!!!!!

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    New Member mohawk's Avatar
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    Re: HPS heat issues...

    Bad news sports fans. That 265 cfm didnt really help all that much. But im figuring that due to the ambient air temp outside the box being a bit high right now... Yep, yep, we have now moved onto the idea of air cooling the reflector with that 265 cfm fan. Im figuring that if we cut a hole into the side of the reflector, hookup the 265 to it, it should suck the hot air right outta there? Now if there is a flaw to our logic, by all means let me know. Cause once we cut that hole in the reflector, its gonna be there forever ya know. Thanks for the help guys

    Mohawk

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    New Member mohawk's Avatar
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    Re: HPS heat issues...

    Despite our hard work and cleverness, the temps have not really changed all that much. Even after making a vent for the 400 cut directly into the reflector using the 265cfm to pull the heat out and a 70cfm drawing air into the box from ground level along with the passive inlets. On a side note, even though the environment isnt exactly optimal, not by a long shot. We have decided to see what happens when you try to grow in a well ventilated area with temps in the 90's. So basically, more work needs to be done, but in the mean time, lets just see what happens all the same

    Mohawk

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    420 Member Retired One's Avatar
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    Re: HPS heat issues...

    Quote Originally Posted by albertgrow123 View Post
    hello my freind,going to\ pass on some info i got from southern weed(i have tried,and it works),cheap co2 cannister is 3/4 a bottle of water,in this tip a cup of pure cane sugar,and powdered yeast,shake vigorously,the chemical reaction creates co2,suspend this above your plants,i was run ning close to 42 degrees,went down for some reason dramatically to 30 degrees,fitted a 4" exhaust,now down to 26 degrees,im using a 600 watt as well,might not work,but for the sake of a bottle of water.............whats to loose,keep the faith my freind!!!!!!!!!
    Try this...it wasn't passed on as a way to keep temps down, although it can happen, but as a way of helping plants tolerate higher temps, with the added benefit of providing the plants with something they need anyhow.

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    Re: HPS heat issues...

    mmmmmmm............exactly what he said lol

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    Re: HPS heat issues...

    Quote Originally Posted by SouthernWeed View Post
    Try this...it wasn't passed on as a way to keep temps down, although it can happen, but as a way of helping plants tolerate higher temps, with the added benefit of providing the plants with something they need anyhow.
    I don't get it. Sorry, i just maybe to stoned right now to understand but what is the way that your are talking about that the plants will tolerate the higher temps. I am having heat issues as well. Your help is much appreciated.


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    New Member mohawk's Avatar
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    Re: HPS heat issues...

    Well, all the help and info from you guys. The temps never came down enough for suitable growing conditions, but these things happen. All the same, we decided that its best to go with a larger grow area. So now its off to sort that issue out now. By the way...
    Its been said that co2 will help plants grow in a higher temp area, help them manage the heat better and all.

    Mohawk

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    420 Member of the Month October 2010 & September 2017 TorturedSoul's Avatar
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    Re: HPS heat issues...

    Seal the light fixture (other than the exhaust and a suitable intake) with a good glass lens. Make sure there are no air leaks in the exhaust duct that exits the cabinet (and hopefully carries the air from the fixture a long way so that the heat it contains does not get transferred back into the cabinet). Add duct from outside the cabinet to the intake on the fixture and make sure it has no air leaks.

    As the "stinky air" in the cabinet is now completely separate from the air used to cool the light fixture, you have more options when figuring out where to dump the hot air. Take advantage of the fact that while hot, this air has no smell - get it completely out of the loop so to speak.

    Don't have the ballast in the room that you draw air from to cool the cabinet if you can avoid it.

    Use big fan to move air through the light. Use the smaller fan to move air through the cabinet (exhaust as high as possible, intake as low as possible). Make sure you have intake holes properly-sized for the exhaust you intend to flow.

    A 400-watt HPS in a 12 square foot cabinet seems a little low to me; are you supplementing it with CFLs?

    CO2 supplementation may be of some help in helping the plants tolerate the heat. It would be much more helpful if the humidity was generally high in the cabinet - and if you increased the light by 22,000-50,000 lumens.

    Making sure that the plants have adequate water to transpire. This is their internal "climate control." Keep an oscillating fan moving air across the tops of the plant to aid in the process.
    Respectfully,
    Tortured Soul

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    Re: HPS heat issues...

    What I did was look at craigslist. I picked up a 5200 BTU a/c unit for $50 that keeps my grow space very cool (down to 68 if i wanted) but I keep it at about 75.