Cave's too hot!

[stone69]

I have a 2x2x5 grow closet with a 250Watt HPS, just replaced the 4 in axial fan with a 4 in inline fan and temps are still running in the high 80's to lower 90's, I thought for sure after replacing the axial fan, the temps would improve a little... no change...
I have to leave the door open to keep it in the 80's..
any idea's.... do I need a turbo fan?

 

[HitTheHazards]

I just set up a similar room and I am just waiting for the temp issues to begin. From the research that I have done lately it looks like the most important issue is goo air in, bad air out. Make sure you have an intake fan that is capable of keeping up with your exhaust fan. Try to match the CFMs as well as possible, if you have a slight difference it won't make for too much of a problem. A lot of people focus too closely on exhaust and not enough on intake. After you have this you can make more detailed adjustments to the air flow like taking advantage of the fact that hot air rises. Ideally you want the intake at the bottom and the exhaust at the top preferably on opposite sides of the room too. Play with these ideas and let me know how it works because like I said, I will be having similar problems soon.

 

[true grit]

Whats the CFM on the fan? Where are you pulling cool air from? I had to up to a 6" or 8" inline (ended up with an 8" canfan-800cfm) for a 600w in a 2'x2.5'x5'. Then picked up a variable speed controller (router speed controller from Harbor Freight-$18.99), and with a sealed vented hood I was able to adjust air flow and get temps from mid to high 80's down to 80-82 lights on with a passive intake. Then dropped an AC vent into the closet the box is in and got temps down to 75-80 with a passive intake and was able to turn down the fan to less than half speed. Now I've ditched the box, sealed the closet and dropped temps to 70-72 lights on high 60's lights off and a lil more room to flower.

KEY to the whole thing being the fan that was way too much, but variable to adjust to conditions.

 

[justanotherbozo]

I have a 2x2x5 grow closet with a 250Watt HPS, just replaced the 4 in axial fan with a 4 in inline fan and temps are still running in the high 80's to lower 90's, I thought for sure after replacing the axial fan, the temps would improve a little... no change...
I have to leave the door open to keep it in the 80's..
any idea's.... do I need a turbo fan?

high bro, what about making yourself a little cooltube for the light?
...then hook that to it's own passive intake and use the inline fan
to exhaust just the light, ...then put the axial back the way it was.

can't be much more help without pictures bro, sorry.

 

[Ganjalover]

still running in the high 80's to lower 90's,QUOTE]

Nothing wrong with those temperatures. Still below border line

 

[stone69]

Picture's

Thanks everybody let me post some pic's, then i'll get back to you...
the fan is rated at 80cfm

This is the intake outside the closet

intake inside the closet

exhaust inside

exhaust outside, I just leave this open going into my bathroom..

the closet

 

[stone69]

Thanks everybody!
HitTheHazards... Yeah, I only have an upper exhaust fan and lower intake with no intake fan, I didnt think I needed one. Stay posted and we'll figure this out...
TG.... hey bro... it's rated at 80 cfm, I thought that would be good enough, at least a step up from the axial fan. I thought about a variable speed controller...will that make the fan go faster? or just slower? I dont have central air, so no ductwork, maybe heat for winter...
justanotherbozo... I had a homemade cooltube on it that just drawed air from the closet to exhaust, it didnt have it's own intake, as you can see there's not much room for anything other than the light, no difference... thanks
GanjaLover... my plants always seem real nice and dark and healthy in the cool veg box... then when they go to the hot flower closet, they seem to loose that nice green luster.... thought it's probably the heat, and when the door is closed it's creeps into high 90's,not much difference even in winter.

 

[justanotherbozo]

high bro, ...can you take a step back and take a couple pics?

a common problem with closet grows is that too often, you end
up just recirculating the same air, which just gets hotter and
hotter.

also, you can't go by what they say on the box with those inline
fans, they are made, primarily, to boost air-flow in a long ducting
run. ...which just means they don't pull air worth shit!

btw, it is almost always best to leave your intakes passive,
if you add an intake fan, too often the fans work against
each other so the intake fan will actually retard air-flow.

 

[been]

You have to isolate the lamp and cooling circuit from the grow environment..... if you know what I mean. Too much airflow and you'll be drying out your girls faster than they can drink water.

 

[stone69]

Thanks Bozo and Been... sounds like a kids tv show...lol.. sorry...
I dont have much room in there, if you seen the pic's, I cant even hardly bend the flex-duct in any angle...
The reflector seems to be what's in the way of any duct-work and I really dont want to re-do the light and reflector...
I'm trying to keep it all enclosed in my home environment(as far as the intake and ducts) and two walls are exerior walls and no interior wall space...
Maybe I can run some ducts down the inside wall... then with a stationary light, I have to deal with moving the pot's up then down...

 

[true grit]

Get something rated 200cfm plus (thats what I'm guestimating, not a solid idea). Yes the variable controller only makes it run slower. I over did it with air movement and allowed myself to go down in volume moved. Not only is this effective, but allows me to grow in size before replacing fans. Trust me, I've realized through trial and error, over doing it is much more cost efficient than under doing it and having to spend at a moments notice to secure the plants health. I spent much more trying to get by on a budget than over doing it and ensuring a consistent to improving environment.

Check out craigslist homie... savior at the utmost. My 800cfm can fan was picked and sterilized for less than $75. Just keep an eye out!

 

[stone69]

Thanks True Grit.... go big... make's since, I wish I would have got a 400 or 600 watt HPS, then I think I could have used lower watt bulbs, if I wanted....
Do your run an intake fan as well?

 

[Ganjalover]

How about inreasing the distance between tops and light by taking pots off stands or by bending LST style. That might help lower plant temperature.
Makes sense?

 

[justanotherbozo]

Thanks True Grit.... go big... make's since, I wish I would have got a 400 or 600 watt HPS, then I think I could have used lower watt bulbs, if I wanted....
Do your run an intake fan as well?

it's good you didn't because using the wrong bulb in any fixture
is unsafe! you'd either create a fire hazard, or you'd burn your
bulbs out real fast!

the only exception to this i know of is if you have a switchable
ballast, and that isn't to switch from one voltage to another
but rather to switch from Metal Halide to High Pressure Sodium.

 

[stone69]

GanJaLover... Theyre as low as they will go, and there's not a lot of room for lst's... that Haze is about to get too tall...
Hey Bozo... I thought I read somewhere that you could use a lower Watt bulb in a higher Watt light system, probably wrong though... thanks

 

[true grit]

Naw, only use the correct wattage bulb for the ballast.

On the box set up I ran a passive intake (aka a 4 inch hole on the bottom of the box) and before I dropped an ac vent in the closet, I would run 4" ducting from that hole to fresh air outside the closet. On 1/2-3/4 speed you could feel the air pullin in that ducting. Then inside the box the hood was open on one side pullin that air across the bulb and out the exhaust side of the box. Cooled that 600w fine...

 

[stone69]

Mine is a 4 in also... so I just really need at least a 200 cfm exhaust fan with variable controller and a passive intake the same size... thanks TG

 

[true grit]

No problem homie and yeah, play with the CFM ratings. The reason I suggested at least 200cfm is that was the minimum I needed with the old tons o' cfl set-up (400w's of cfl) which I would think would be comparable in heat to a 250 hps, probably a little warmer....

Just in your interest of expansion I would look for a good hi-flow 4" inline, or a nice 400cfm 6" inline. That would be more than adequate to cool what you got and be capable of cooling a 400w at least in the same space or larger in a new space (expansion is always inevitable! ha) They have lots of CFM/room clearing calculations, but thats just airflow, not temps and external factors. My 8"Can Fan is quiet as shit, especially with the variable controller only running half speed. Much quieter than a bathroom fan. The other 4" inline I had was WAY too loud. And I think once I started moving that much more fresh air with the big fan, the plants were much happier!

Good luck homie!

 

[been]

I don't really understand what's going on with the layout of your closet. Is the intake in the same room as the exhaust? Bozo asked, but I didn't see a response from you... or I just don't understand the answer.

You could open up the hole underneath that vent cover. You could get a bigger fan or an air-cooled reflector and the best ducting money can buy, but if your exhaust is recycling through the intake you're wasting time and money... for you see, time is money.

 

[stone69]

No the intake come's in right by the door and the exhaust exit's in another room.