cab cooling PLEASE HELP

[biffmcnielly]

just set up my new cab today. I have a 400 w internally ballasted light, in a 3 x 2x 5 foot cab. I am running a 185 cfm fan which is sucking through a carbon scrubber. I am new to the hps light thing, but it felt a little hot, it got to 104 inside the cab with the doors closed, and the kids got a little sunburn. with the doors open it got to 84, and down to 75 with the doors open and a fan blowing inside.. any suggestions or ideas would be a great help.....Thanks for reading

 

[Moneygrowonweed]

Question can you leave the door open?
if you can i would put a oscillating fan at the door to blow air around and out would drop temp a bit and keep the kids from being burned
or if the door needs to be closed upgrade the 185 cfm fan to a 400 or 500 cfm that also would help out a lot. hope this helps peace

 

[aceofspades]

I have a 4'x2'x6' ( lxwxh ) and I used a 400 watt, and had a 175 cfm fan and it was pulling through a DIY carbon scrubber. I get up in temps around 86, but all in all I have had good luck. I just recently bought a 400 cfm fan and will be running it with my 600w light in a smaller area. I say a bigger fan for you and get some fans running in the cab blowing over the tops of the plants, I think you will be fine.

Ace

 

[geopolitical]

Do you have any air intakes? Where is the fresh air coming from?

 

[M3@n_0n3]

Try removing the mylar for one thing. Everything is so close in there you are probably creating hot spots.

The heat issues are going to get worse the taller the plants get.

Upgrading the ventilation would help also.

Adding a circulating fan might also help.

My cab is similar in size I use a 80 cfm exhaust (4") with passive intake (24") and a 10" circ fan. The key difference is I only have a 150w HPS in there.

Had two 150's at start and ran into the same heat issues you are having. My highest temp was 106 degrees w/ 2 - 150 HPS. Reduced from 300 watts to 150; temps are currently running at between 68 lights off and 81 degrees F lights on.

My current issue is odor! The mom I am flowering smells up the whole house! This is less than 3 weeks into 12/12! 16 days to be exact. So I am going to have to upgrade my ventilation, the 80 cfm won't pull through a heavy sock, let alone a carbon filter!

 

[FreezerBoy]

Fresh air good.

Consider moving the ballast outside the cab. Those things get hot.

 

[DiscoBiscuit]

Take the duct off the south end of the scrubber. It's robbing the scrubber's ability to suck 100% heat out of the tent. As it sits, it's sucking 50% heat above the light and 50% something else from below. I assume it's cooler air coming up the south duct but you need this cool air free and circulating inside the cab, not sucked out through a straw.

 

[biffmcnielly]

not much in the way of intake for the fresh air until tomarrow. I am also gonna try to cool the light. how much fresh air intake do I need, I have 4 inch ducting

 

[Norrath]

cool air from somewhere would be nice, a constant flow..

you say it gets down to 75, but making sure your ambient temps are tdiffed properly to the amount of radiant energy being let off by your grow is a surefire way of keeping it cool.

edit - i think i understand it now, the air is coming up from plantlevel through the fan and out the cab? you will really really need to make sure your ambient temps are down or is sealed well and you have cool air coming from somewhere, as it doesnt look like an aircooled hood, which would help tremendously.. if im wrong and it is, still look at ambient.

i digress, had the same looking cabinet myself, i couldnt make it work, needed a bigger area for my 400w in already ambient temp of 70-75:/ WITH aircooled tube..

 

[M3@n_0n3]

As DB says heat always rises, cool air is always at the bottom.

Passive ducts should be near the bottom.

The important thing is to evacuate the hot air from the cab.

With the passive intake being 3x the size the exhaust? Am I correct with this DB?

 

[M3@n_0n3]

As Norrath said, needed more space for his 400w light. Got to get yo shit dialed in. Try it, fix it, try it again... It's a learning process! Just keep us informed!

 

[biffmcnielly]

well for tonight I 86'd the hps and jerry rigged 3 100w cfl's. tomarrow I will work on cooling my hood.

the ambient temp was about 72. and most of the heat was generated by the bulb, as most of the heat was below the light.... It is a knockoff of the sunburst light. I will ask my local grow shop about cooling it.

I will also have to work on the fresh air intake. I am in an apartment so stealth is the key.. I am trying to keep this in the DL..

I hope I dont kill the girls in the learning process..... THANKS for all the help so far

 

[messn'n'gommin']

With no intakes, the fan is just, essentially, churning and only exhausting what air it can pull through the cracks and crevices while the door of the cab is closed.

btw...How do you have your scrubber setup? Am I not seeing things right or do you have your ducting on both ends?

Namaste, mess

 

[Norrath]

AND let's not forget how inefficient those 4" ductings are....

i went with a DR120 now 2x400w verti

 

[biffmcnielly]

the scrubber is in the corner.. it wasnt hooked up in the pic.... I opened up the cab and was trying to suck the heat out from around the plants...

scrubber in the corner up to the fan hanging above the light, and out the side...

I was afraid if i had big old intake vents the smell would seep out of them

 

[Norrath]

youre asking too much of the fan pulling through the scrubber AND that 4" ducting. i had an eerily similar set up to you, i tried the scrubber up high in the cabinet, standing in teh corner on the plant platform, and even tried perforated strapping it to the back wall of the cabinet with a shorted run of ducting.

i also use an inline fan, S+P 6" mixvent

but now i use it with 6" ducting, and wouldnt even consider anything smaller...even with a good fan. it's called dryer vent in laymans for a reason..

just cant get enough air out, even with decent ambient temperature, it will build up and cook them without decent exhausting..

i think my highest temp was 113F with an average in the 90's...

time for ac

 

[Mr-B]

Go pick up a Vortex or Can fan. 165 cfm doesn't have power to pull air through the scrubber and push it outside.


I have 2 lights in my 5x5x8' tent. A 400W and a 600W.
I'm using a 8" inline fan with a reducer to make it 6".
Cool air is pulled from outside the tent, routed through the lights and back outside.
My http://www.icmag.com/ic/picture.php?albumid=11648&pictureid=234403 scrubber is hooked up to a 365 cfm Vortex fan and is set to come on if the temps get above 82 degrees.
The temps so far haven't gotten above 80F using the 8" inline fan.

here is a pic.





Good luck.

Bhttp://www.icmag.com/ic/picture.php?albumid=11648&pictureid=234403

 

[Matanuskan Flo]

def place curved or rounded vents at the bottom to create the natural convection cell to eliminate heat. the bottom opening should be rounded to promote Laminar air flow, not turbulent. turbulent airflow should be directed at the plant directly. the laminar flow from bottom will convect naturally to the top exhaust. your exhaust must always be more powerful than intake. so, i would suggest a single computer fan at bottom instead of a passive intake & a more powerful exhaust, esp if u have scrubber. other suggestions would be to remove the ballast from cab, make sure the exhaust is before the scrubber & not after or upgrade your exhaust fan. 180cfm is really quite miniscule. it would take over 30 mins to fully replace air in the box with that fan based on ur dimensions.

 

[messn'n'gommin']

A good rule of thumb is to have twice the size of intakes as exhaust. e.g Two 4" intake ports and one 4" exhaust port. Cut two 4" holes somewhere towards the bottom of the cab and hook up your scrubber. Close up your cab and take your temps at the exhaust port and intake port. The difference is how well your fan is doing its job. As long as your fan is exhausting enough air you should be ok. The fan you are using may still be a bit weak for the amount of heat you have, but, you should still notice a good size drop in temps.


Hope this helps some.

Namaste, mess

 

[SmokinSHO]

-