Houston we have a problem....

[Art Vandelay]

First off let me say thanks to everyone this is by far the best site on the net! I have a new cabinet dimensions are 17x17x30 so fom my calculations around 8 cubic feet?


I have 4- 2" passive intake holes,one in each bottom corner of the box.
Box is elevated a couple inch's off the ground on casters.

One exaust 4" going into a seperate chamber measuring 8x17x30 fan is a cooltron fa1225b11t996. 120 x25 mm airflow is 68 cfm speed 2500 rpm at 39 dba.

Going to run cfl's 6 to eight 23 watt bulbs off of a power strip with three y splitters.

My problem is heat aahhhh!! Temps are in the 90's I want my set up to be stealth so bought or made carbon scrubber in the next couple of weeks.

Seeds are grapefruit crush and growing in ffof seeds started in happy frog" going to lst one plant and take some clones until eventually a perpetual sog. Again much inspiration. The Dr" , Urkle, Anti, Blynx mad props and again thanks to all who contribute I've gotten this far. But need some help a.s.a.p.

I've read the ventilation 101's and many others and can't wrap my head around the numbers and charts etc... Thanks Art out.

 

[detoneSmoker]

http://www.microcenter.com/single_product_results.phtml?product_id=0274204

Got that in my cab...working really good. 140+cfm in one fan. not to loud either. Maybe add a cpl more intakes? Low 90's isnt optimal but you can def grow in that temp. Just a little trickier. Dont even try 94+.

 

[oneshot]

One exaust 4" going into a seperate chamber

Care to elaborate? Hard to picture your exhaust setup away from the lights.

Easiest solution to try first, get a better PC fan

If you could post pics of the setup it would help.

 

[Art Vandelay]

Thanks for the reply Detone, was thinkin. my fan slows down when I close the door and speeds up when I open it?? I saw a link on that fan early on new egg? Could I run a homemade scrubber on that ya think?

 

[oneshot]

Thanks for the reply Detone, was thinkin. my fan slows down when I close the door and speeds up when I open it?? I saw a link on that fan early on new egg? Could I run a homemade scrubber on that ya think?

That means you have positive pressure and something is blocking the output of the fan. The air is not escaping.

 

[Herbophile]

You need more intake area. A general rule of thumb is double the area of the exhaust. So your 4" exhaust has an area of 12.5. While your 4 intake holes are only 12.5 also, a one for one.

I would either increase your intake holes to 2.5-3" or add 4 more 2" holes.

 

[Herbophile]

Also like oneshot asked. You say you're exhausting into a separate chamber. How does the air get out of that second chamber?

 

[oneshot]

I have always liked this part of the Ventilation 101 thread:

Thanks to Freezerboy for the nice picture. This is a common mistake when using a number of small holes to equal one big one. The only solution is to calculate the area for the big hole and divide by the AREA of the smaller holes to get the number of small holes needed.

In this case one 9" hole needs 80 x 1" holes to be equivalent.

I'd like to point out that making one big hole is better than a bunch of little holes as each little hole has it's own Vena Contracta losses which do add up.

It's a common mistake.

 

[Art Vandelay]

The second chamber is wide open right now until I get heat issues fixed. The cab design I saw on g.c. Micrgrow420's box if you have seen it. I'll try to get some pics. Intake seems to be the issue? Thanks for the quick response. Herb and one shot. The intakes are actually 1 1/2 inch plumbing fittings.

 

[detoneSmoker]

Thanks for the reply Detone, was thinkin. my fan slows down when I close the door and speeds up when I open it?? I saw a link on that fan early on new egg? Could I run a homemade scrubber on that ya think?

Mine has a homemade scrubber on it and moves alot of air still.

 

[oneshot]

The second chamber is wide open right now until I get heat issues fixed. The cab design I saw on g.c. Micrgrow420's box if you have seen it. I'll try to get some pics. Intake seems to be the issue? Thanks for the quick response. Herb and one shot. The intakes are actually 1 1/2 inch plumbing fittings.

GL man! This is a fairly easy problem to fix.

 

[Herbophile]

Being that they are only 1.5" holes that fan is really struggling trying to move air. Easy fix.

Another thing that I thought of while pondering this is to make sure the air you're exhausting isn't getting drawn right back into the cab. I'm assuming that by exhausting into a neighboring chamber that the air isn't getting diverted away from the cab. This is pronounced now because you're not moving enough air. Once you're moving the correct amount of air the velocity of the fan should blow that warm air enough distance for it to mix with room temp air. It's just a thought and something to keep in mind.

 

[Art Vandelay]

Thanks herb, I have this box inside a closet right now trying to keep it as quiet as possible. With my airflow issues fixed this fan should,in theory be able to keep this cool and maybe homemade scrubber or better fan advised as well.

 

[Art Vandelay]

O.k. I put 4 more holes in the box, room temps in room 78 my temps in the box still over 90 with total of 8 - 1 1/2 " holes. Do I need more holes ,bigger fan? The strain in the fan is gone when I close the door so that's a plus. Thanks for any imput.

Also is there a link on how to post pics so I could put some up.

 

[oneshot]

Can you drop the room temps at all? Remember, BIGGER holes > MORE smaller holes. I posted the diagram above.

To post pics here you need 50 posts. You can use a public image hosting service like imgur.com if you want to risk any possible 'security threats'. Once you hit 50 posts here you can safely upload images.

 

[Art Vandelay]

All the holes are on the bottom of the cab 2" with one and a half fittings, two elbows in a s shape. Is this also cutting my intake?

 

[Art Vandelay]

How many more holes you think i need? And is there an easier way or better way to divert the light all holes in the base 17x17?

 

[oneshot]

I really think before you start drilling more holes and making modifications, we need to see pictures :/

 

[Art Vandelay]

I'd better get to posting then thanks

 

[blackosprey]

Hey, another way that you can lower temps on your plants is to install a plexiglass light shield. take a look in this thread...
https://www.icmag.com/ic/showthread.php?t=31605

This is what I did with my box. The heat coming off my lights is 88-90degrees, while my growing chamber remains a pretty constant 78.