Please Help! (Heat Issue)

Discussion in 'First Time Marijuana Growers' started by CorpAmerica, Jan 22, 2010.

  1. Hey Everyone,

    Im hoping you can take a look at my setup and provide me with some tips as to what I can do to lower the temperature in my box. Right now the temp is sitting at 88-91 degrees and dosnt seem to want to budge.

    Ive attached some pictures so you can see what im working with. In the pictures the left ducting off the fan is pulling air from outside, its now been cut and the flange sealed to pull the air from inside the box. The intake pulls air from the top of the room, runs it through the light and then pushes it out the other side of the box. I do not have intake holes in the box yet, but there are gaps around the door that I can feel the air pulling in through.

    I have a fan circulating the air on the inside but im not sure that its strong enough (about 135 CFM). and I also had about a half pound of dry ice in a insulating container near the circulating fan.

    As you can see in the first picture my therm/hygro is mounted at about the level of the hood. I almost feel skeptical that the therm is lying to be because it dosnt feel 90 inside the box... but I figure it knows better than I do.

    I dont currently have my hydroton in the pots, I was hoping to get the temp issue figured out before it becomes a bitch to move the pots. Will putting the hydroton in the box and starting to run the hyrdo system bring the temp down?

    Id really need some help with this, the ladies are supposed to be arriving in the next day or two and I dont want to have to delay sprouting because I cant get the heat under control.


    Attached Files:

  2. Needs more intake holes. Simple as that. You could have a pinhole and of course you would feel air getting sucked in, obviously it's not enough though. The exhaust will only be able to pump as much out as it can get in.
  3. ^Yup. You have no cooling air flow. Like sucking through a straw with your finger over the end. You need more/bigger intake ports.
  4. ur plants sit on top of the fan right?

    im with them, u just need to let in more air. sick a wedge in your door to leave it slightly cracked open. if ur temp drops to where u want it, u know u need to cut an intake port.
  5. Thanks guys for your advice, ill try leaving the door open a bit and see what that does to my temps. Ive been really hesitant to just start drilling holes because im trying to use the dry ice as supplementary CO2 and dont want it just escaping... but I guess less CO2 is better than dead plants...

    alvinhydro/needa - where you see the fan positioned is actually a sub level from where the plants will be grown, in this way Im using all of the floor space I can for grow room.

    Do you guys really think ill see a 10-15 degree by increasing the air intake?

    Would there be a noticeable difference if I increased the size of the circulation fan?

    I attached an image so you can see the full set up... please excuse the tangled cords, still working on it.

    Attached Files:

  6. Alvinhyrdo - Yah ive read that before, but thats not foil its actually 1 Mil mylar, which I dont think creates the same hot spots that a true metallic foil would.

    Luckily I have white paint under the mylar... Although with how difficult it was to get the mylar up Id rather not have to pull it down in the experimentation process.

    Anyone else have thoughts on keeping this baby cool?
  7. You will easily get a 10-15 deg drop with proper air flow. As mentioned above, leave the door open and watch the temps drop. Ideally, your intake should be twice the size of your exhaust. You have a 6" exhaust duct, right? That's 28 sq. inches of cross-sectional area. Your intake should be at least 56 sq. inches.
  8. Thanks Johnk - Thats a great statistic to know.

    Did you find that in a guide or in some literature? Im curious if there is a must-read guide ive missed somewhere because I dont remember seeing that figure in any of the intro guides.

  9. Quick update on the heat issue. I left the door about 3 inches open with the full system running for about 3 hours. Temp seems to have leveled off at 82! I think with better circulating fan positioning so that its drawing in the cool outside air I should be down where I need to be.

    Thanks for you help guys... Ill post another update once I get a circle cutter and get the final ventilation holes drilled and fan/dryice rigged.


    Attached Files:

  10. It looks to me that the fan on the floor would be more effective if it was pulling the air from the top of your closet rather then the ground. It will expel the hottest air from the room rather then the coolest!
    Good Luck!
  11. The fan on the bottom is pulling air from the top of the box. The ducting that you see on the outside of the box runs up the side and connects to the light, where the air is taken in. I just mounted the fan in the bottom of the box because its a nice, clean configuration and with the fan inside the box the noise is muffled to some extent.

    Just as an update here... Ive had a couple of threads going on this problem but as of now Im picking up a 14,000 BTU A/C unit that will serve to cool the entire closet that the box resides in. This should eliminate all heat issues and allow better control over the temperature.

    Thanks for all the insight guys.

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