Temperature Issues in new cab..

[gnaut]

So, some people have been following my cab build, everythings fairly swell.. but one thing. Temperatures are 90* running 600w, and 87 degrees running at a dialed down 300w in a 2'x4'x'4 space... my cab in detail is in my sig, and I assume that this is an intake problem? I have a 334 CFM can max fan exhausting air over a sealed cooltube (the tube is cool to the touch after running for four hours. and the air exhausted by that is not hot at all.

I have a 454 CFM fan exhausting air out of the room pushing through a phresh filter carbon scrubber.

Now, it doesnt feel too hot, but, i doubt the brand-new thermometer is off by too much.

So question, before i go assuming and drilling more holes, is this an intake problem? The only thing I can think of is that it is not moving the hot air out of the cab fast enough.

 

[GP73LPC]

your intake should be twice the size (volume) to your exhaust, or so they say...

plus your fans are way overpowered, but that should help... with 32 cubic feet that fan should be changing the air inside ever 4 mins... shouldn't have time to build up... increase your intake hole...

 

[gnaut]

i have two 6" holes cut in the bottom and 1 6" exhaust... should i double up?

 

[GP73LPC]

well i just looked at your plans and the positioning of the intakes looks ok. at first i thought maybe they were too close...

i guess it could be back pressure from the scrubber.

can you detach it and see it your temps drop?

 

[GrowBox420]

is the intake all passive?

 

[gnaut]

all of my intake is passive, yes. i'll take some things apart and see if its the scrubber tonight... but even with the scrubber my fan CFM is still running on overkill.

 

[GrowBox420]

What about adding a PC fan on the existing intake (instead of cutting a bunch of holes), and adding a fan that blows parrallel to the hood or a fan in general to oscillate air?

 

[oneshot]

I have a 454 CFM fan exhausting air out of the room pushing through a phresh filter carbon scrubber.

This could be a big problem. I believe you want to PULL air through the scrubber. It greatly effects things.

edit:

Looking at this picture:

I am assuming the cooltube exhaust is going right out the top of the right hand section? Hard to see with the green lines.

What could be happening is, the Can is exhausting the air out the top and the vortex is immediately just sucking in that warm air being exhausted right up through from the bottom? You said it's not hot but who knows. Could also just be a simple intake problem as discussed already

It's hard to tell from your thread. Not enough detail of the fan/filter placements.

 

[gnaut]

the cooltube is being exhausted through the top of the cab, out of the back.

Under that shelf, is the scrubber which is pulling air from both cabinets. And, I wouldn't even go to as far as saying that the air is even warm that is being exhausted from the can fan.

I'm going to go do a bit of moving around and checking a few things before i make any larger changes. But as i see it, i feel like its an intake problem from an engineering stand point.. but who knows..

 

[GrowBox420]

What about adding a PC fan on the existing intake (instead of cutting a bunch of holes), and adding a fan that blows parrallel to the hood or a fan in general to oscillate air?

... sounds reasonable

 

[Newd]

gnaut,

Where is the thermometer located?

Are you picking up radiated energy?

Best regards,

Newd

 

[gnaut]

I've been placing it in corners of the cab, i've currently reworked some of the ductwork and letting the lights run to see the temps... the first time i set it dead center in the middle of the cab,

 

[MrStonerMan]

Do you have fans running under the hps lamp where the tops of the plants would be? that might help out a bit. Also it might be where you're measuring with your thermometer. To me it seems like you need to direct your air a little better. Maybe try sucking in air from outside through your cooltube?

 

[gnaut]

the air coming over the cooltube is only coming from fresh air from outside of the box. it is sealed and has the canfan dedicated to cooling it. and it is quite cool.

 

[marrdogg]

Can I make a suggestion, If you look on ebay under heat exchangers you will see where there are actual icebox type of chillers for computers. If you have a chiller you could use these to cool your grow box cause I do. If you do not have a chiller just get an old window mount ac unit and convert it to one very easy, you would only need a 5000-6000btu unit for your space. You could also use it to cool the incoming air to your lights. Also on ebay are actual icebox chillers that I see for $45 for the 8in. From experience I would get the 8in and reduce it it gives greater surface area for the fan to blow across. I too had heat issues growing with a lot of light in a small space. I tried all kinds of things but could never get temps where I wanted them. And believe you will need to damn near run a tornado thru there to keep temps where you want them. Can say if you get that chiller you can maintain your temps around 75 with no probs just got to keep humidity in check, hope that helps. PEACE!

 

[Dr 4 four]

This is just my two cents, but it could be your placement of the intake to the scrubber isn't high enough to pull the hot air from the top of the cab. How are the temps from the veg side of the cab? I wouldn't think there would be a problem there since the scrubber is pulling from the top and your running t5's.

 

[GP73LPC]

i keep wondering about the power of the fans... it's really too much for such a small area.

i'm wondering if the pull from exhaust is so strong it's pulling directly from the intake without affecting the rest of the inside of the grow chamber. sort of like a jet stream...

 

[gnaut]

actually, theres a slight adjustment to the veg cab, the lights in both cabs actually hang at the same height, holes at the same level. Temps in Veg cab are stable at 78, warmer than i'd like, but more than acceptable.

The difference is.. there are two 6" holes for intake in a 2x4x2 area, as opposed to flower where there are only two for a 2x4x4 area. I'm going to pick up an oscillating fan, and open up some more intakes and see what happens tomorrow.

 

[gnaut]

Can I make a suggestion, If you look on ebay under heat exchangers you will see where there are actual icebox type of chillers for computers. If you have a chiller you could use these to cool your grow box cause I do. If you do not have a chiller just get an old window mount ac unit and convert it to one very easy, you would only need a 5000-6000btu unit for your space. You could also use it to cool the incoming air to your lights. Also on ebay are actual icebox chillers that I see for $45 for the 8in. From experience I would get the 8in and reduce it it gives greater surface area for the fan to blow across. I too had heat issues growing with a lot of light in a small space. I tried all kinds of things but could never get temps where I wanted them. And believe you will need to damn near run a tornado thru there to keep temps where you want them. Can say if you get that chiller you can maintain your temps around 75 with no probs just got to keep humidity in check, hope that helps. PEACE!

mind tossing me a link on that chiller? thanks man!

 

[HandsomeVulture]

The difference is.. there are two 6" holes for intake in a 2x4x2 area, as opposed to flower where there are only two for a 2x4x4 area. I'm going to pick up an oscillating fan, and open up some more intakes and see what happens tomorrow.

Is it perhaps possible to put the intakes anywhere other than the bottom of the cab? Is the back wall an option at all? Or is that gonna cause problems with light leaks? If so, you could get a dark room louver for like $30 (or build one).

I ask only because once you get plants in there it's only going to restrict the airflow from the bottom even more.