AAAARRGGHH!!! I DONT UNDERSTAND!

I've just completed one grow in a 1.2m * 1.8m closet, its 3m high too.
I had to keep the door open, and with just a dinky little fan blowing on them from the doorway, they managed to stay at about 27C all the way, under a 400w HPS.

For this grow, I decided to do things a little better.
I smacked out a 12 cm round exhaust hole at about eye level and a 10cm intake at roughly floor level. I inserted the 12cm flex ducting, pulled it all straight and inserted it into my brand new fan which I've set up with a cooltube around my 250HPS.
This is supposed to be my prototype for my bigger lamp which I want to add in a few weeks, once it too has become a cooltube.

I bought a 100 dollar ductfan, 350m3, which was pretty much the biggest fuuck I could get hold of:

TD 350/125 (125mm/360m3/hour) - Hydroponics UK, Hydroponics Systems & Grow Lights

then I connected it all up, turned it on, and stepped back in anticipation.
33 fuuking Centigrade with the door closed, after 20 mins.
about 29C with the door open.

So this whacking great fan which sounds like a monsoon, and is inserted into a cooltube is doing a much worse job at sucking out heat, than my old 20 dollar fan was at blowing in cool air.
What am I doing wrong?
It's driving me nuts.
Also, I have 7 babies that desperately need to get in there quickly.

Things that are confusing me:

The cooltube glass is cool but the air around it is fairly warm. Since the exhaust tube from the cooltube goes to the exhaust opening in the closet wall, how is other ambient air in the room supposed to exit? Do people have double exhaust holes in two walls opposite or something? One for the cooltube, and one general ambient air exhaust?

The fan seems to blow like crazy, but theres not much sucking going on apparently. Wouldnt it be better to reverse the cooltube, and have the fan stormblowing the air across the bulb, through the cooltube, into the flex ducting and out, rather than trying to suck it out?

The exhaust hole is on the same wall as the intake hole. I know thats not recommended, but I had little choice, though I could perhaps make a hole on the other side, with some difficulty. I would think this does not matter much since I'm leading the exhaust air through ducting.

Any help would be amazingly appreciated, I've been grazing my knuckles banging holes and wracking my bleeding brains for 3 days now. :mad:

*Rolls a depressed spliff*

do you still have intake going, thats where you may be having issues you may need intake for cooler air, if i stop my intake my temps rise over 90F and with intake on it stays about 80F.

Hmmm, no, someone said intake wouldnt do much so I turned it off most of the time I've been experimenting, though I haven't noticed much difference.
I'll try it again and see what happens.

Intake low... exhaust high... take advantage of warm air's natural propensity to RIIIIIISE and float away... You want another vent of some sort low down.

Quote:

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You want another vent of some sort low down

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Please tell me more about this...
What height?
Must it be opposite because thats a hassle?
What size?
Does it need an exhaust fan?

a simple passive intake is all you need

hmm

if your ambient temps are high then you arnt going to be able to cool things down too much with passive cooling, you need to cool the room down somhow, or draw cool air from somwhere..

the only benefit to blowing air through the cool tube ( as opposed to sucking it out) is; its easier on the fan bearings, so your fan will last longer

Passive cooling means?
The room isn't hot in itself. When I turn the lamp off, the temps settle to normal house temps of about 22C in 10 minutes.

What I dont get is when I blew a crappy little fan over them with the door open the last grow, the thermometer registered around 27c. With a great freaking hi-tech fan and two massive holes in my wall, but no little fan blowing over them, I'm getting around 31C. WITH A SMALLER LAMP!!!:(

What about chopping off the sides of the reflector?

To the top.
I really need help guys!!!
Should I make a new hole in the brickwall on the opposite side?
Will that make a worthwhile difference?
What should I do?
:confused:

hot air rises.
so you exhaust at the top of your cab...

you always need to provide your cab...with fresh cool air and cool air is lower to the ground...So, fresh air intake should be at bottom...exact specs...don't matter. cool in: bottom........hot out: top
Whoever said you wouldn't need a fresh air intake is an idiot, and knows nothing of controlled environment issues.

try that and it should work...You might be better off with just an intake and exhaust and forget the whole cooltube effort...See if that works. Goodluck

No, I have all that. I just turned the fan to the intake at the bottom off, because someone said a passive intake is enough.
Its on now, and it seems to keep the temps at about 28C, which is nowhere near good enough for when I add another 400W in 3-4 weeks..


Naturally, I have an intake low down and an exhaust high up. Check my first post for specs please.
And I've tried dismantling the cool tube and just sucking the ambient air, and it doesn't seem to make much difference.

don't have time...just trying to help. if you got it good, I'm gone...peace

Well, thanks for the help...But I don't got it good...:(

I will try to get back to you very soon...hang in there

OH yeah...please convert your values to standard from metric...to save us time. I mod 3 sites and own 2 others...So I stay bbbbbuuusssssyyy!

The room is: 3.9'*5.9'
Its about 10' high.
Intake hole low down is 4"
Exhaust hole about 6' up is 10"
10" flex duct leading about 4.5' from the fan to the exhaust.
The fan is 10":

TD 350/125 (125mm/360m3/hour) - Hydroponics UK, Hydroponics Systems & Grow Lights

Converting m3h and cfm seems hard, but I think the fan is 212cfm - (360m3h).
It's two speed, which seems to have to do with how you wire it. I thought perhaps I had it wired to low speed, but after checking the diagram (not that I really understand it) I dont think so...
I have a small fan as well that I'm using to blow in cold air through the intake.

However, the exaust and the intake are drilled in the same wall, not opposite each other, as is the norm, but I don't think that should matter since the flex duct from the fan/ the cool tube is fed to that hole.

Should there be another exhaust for ambient air?

.

faithless. Its OK to have your exhaust and intake on the same wall. You will want a fan in the room to spread that fresh air that does come in around inside the growroom. You might want to figure out the schematic to your fan. Or take a close up pic and let us figure it out for you.

yes is you have your light isolated from the grow room, which sounds like you do, then yes. you wiull need two exhausts

where is the intake for the fan that is connected to the cooltube? is it set up like top or bottom?

or like this?

Thanks for taking the time.
Heres a quick diagram of what I have:

no problem, frustrating huh. What are the ambient temps around the grow room. ie, what is the temp of the air coming into the room via the 4" intake? You might want to crank that fan up as high as it can. I see the tempo in my room go up 5 deg. F when my light comes on.

if there are two 90degree elbows in your ducting that is why you cant exhaust as good as you want, move your light up the top and raise your plants to the light so you can get rid of the bows in the ducting.

yeah, that would help invision, but realistically, lowering the plants every couple of days?.....a lot of work, and supplies...or do you have an easy method?

Hmmm, but that would move them away from the cold air inlet.
Might be worth a try though.
The ambient temps, air coming in, is around 21-22c.

maybe crank up your exhaust. seems like you have you ducks in a row. I do have my fan blowing on my light. I dont know what works better, i never tried the other way. I run the vent for my light completley separate then the vent for the grow room. Two fans going out, and 1 coming in.

you might try cranking up your exhaust. I run me vent for the light completley separate from the vent for the grow room. Two exhaust fans, one intake, and passives as well.

Hmmm. Looks like Im banging another hole in my rented apartment...:(

this is my set up. it works well. I still see the temps risae when the lights are on

ahh, that sucks. How do you have a lease there?

Well, these first two holes I can cover up with a casing quite nicely, but a third one in that small old built in closet is gonna start looking pretty suspicious...So Ill have to do it on the opposite wall, which leads into a 10" gap between the closet wall and the bathroom wall.
But its the last hole I dare make I think, so I really need to know where to punch it, what height etc. Do you have fans in all the openings in your diagram?

Btw, thanks so much for taking the time :)

faithless,The fans I drew are whatI have. I have little oscillating fans inside the room, but those are beside the point. What hole are you gonna punch? Can you draw a pic of what you plan on dopinw...kinda like mine?

you might try settin up your fan to "push" air thru the cooltube, then straight out the wall.

i suggest staying away from those inline duct fans. They suck ass at pulling air long distances. You need a inline centfirgual fan. Check em out...

I use Vortex. Faithless, the fan in the little pic i have drawnmost recently is a 4" vortex and the one hooked up to the light is a 6" vortex.

Yeah, Im think of punching it halfway down and on the opposite wall, where the diagram shows "New Exit". That way I have 2 exits, one midway and one higher up to experiment with. I guess I'll have to find out through trial and error which exit will work best for the Cooltube exit and which one will work best for ambient temps exhaust?

Will I need another similiarly sized fan for the ambient temps exhaust? Cos they're pretty loud and expensive...:(

About its capacity...any stronger than that and my coats hanging in the hall where it exits will start flapping. Theres a lot of air being pumped out...

With the lower exit hole I could try your method.

Another thing that might help is putting a little tower fan($20) right in front of the intake to suck air in and force the cool air up to force the hot air away fro the plants. In my set up I have a regular old bathroom exhaust fan to suck air out and started with 4 4" air intakes. The temp was too high so I cut 7 more intakes and the temp didn't change. The problem was that the air needed to be circulating around the room and a little tower fan in the corner droped my temp by 10 degrees.

If I were you I would put the new exit in with a fan to suck out the air. I read somewhere that every 90 degree turnin tubing causes you to lose 1/4 air flow, so you are running at half with the 2 turns compared to a strait tube. If it is flexible maybe straiten it out so it runs at an angle from fan to exhaust with as few turns as possible.

=I would get another fan. Have a dedicated room ehxaust and havew a dedicated lamp cooler. Try a fan in the room. Look into a Vortex fan, or something simlar. Id put that fan you have now as my room exhaust, and invest a little into a larger cetri fan and hook that up to your lights.

try a few thing and let us know what happenin.