add a little more fan maybe?

[juggaloscrub]

Ok here goes, my first grow. I am running in my flower room which is 9'x11'x7' 4x 600w hps lights all with vented reflectors. They are connected with flexible aluminum ducting. I was looking at the sticky where it shows the calculations for configuring your cfm and I'm not sure my 746, i think, Can Fan 8" HO fan is doing the trick. I have a couple of 90 degree angles and with that formula it says i need 1320 or so cfm to maintain appropriate venting. I am having a little heat trouble, staying around the 94 degree mark. I was thinking about adding an intake to my sealed room however the air from my basement is pretty warm itself. That or maybe adding another fan directly to the end of my can fan filter to up my exhaust power a little bit. should i try one of these before the other? also i am running co2 via propane burner. <- not causing the heat problem though because I have just switched to flower and have not used it yet and i am aware that this will also increase the team and that i need to run around 85 or so for the co2. I am using an environmental controller as well. Any help would be great, Thanks!

[GetThisOrDie]

Whats up?

Is it possible to run an intake duct from upstairs or a cooler room?

Where are you venting your hoods? If you are venting them into the room that is your problem. If you vent your lights outside or into a different room then your temps should come way down.

Also im not sure because I dont use CO2 but from what ive read it enables the plants to tolerate heat better. Dont take that as gospel because Ive never used it but thats what ive read. Hopefully someone who uses CO2 can comment on that.

[bigsby]

First, let's run the numbers:

9 x 11 x 7 = 693 / 5 (total exchange every 5 minutes) = 138.6
x1.5 for each 90 elbow = 69.3 x 2 = 138.6
x1.3 for the carbon filter = 41.6
+10% for each foot of duct including lights. I'm going to guess 10 feet of duct work = 138.6
Each hood adds resistance. I suggest we use a x 1.2 for each hood = 27.7 x 4 = 110.8

Now we add it all up:

138.6
138.6
41.6
138.6
110.8
-------------
568.2 CFM

You should be fine with that 746 CFM fan. You said your grow room is sealed. Does that mean there are no passive intake vents? If that is the case then that is likely your problem. You need to add them. The rule of thumb is that the intake should be 1.5 the exhaust so with an 8" exhaust you will want 12" of intake.

If you are truly running sealed grow then I suggest you add a vent for your lights such that the lights vent in a closed loop whereby the vent goes from external into a duct through your lights and back out. No need for carbon filter in that loop. My read is that you are not really doing a sealed grow room in which case cut the vents so that your fan can do it's work. It doesn't matter if it is pulling warm air. Anything will be cooler than 95 degrees.

[juggaloscrub]

First thanks to everyone for the replies. Ok I think I am going to attempt an intake. how i have it set now is the carbon filter is on one side of the room, from that comes out ducting then i have a Y splitter for the ducting that goes from one 8" and splits into two 6" for the light hoods. then goes across and the two sets of two lights are connected and the ducting continues to another Y connector that converts my two 6" runs into a single 8" again then that connects to my exhaust fan. I did throw that term sealed room out there loosly because my room has no intake vents an i put in hella work makin sure every inch was sealed up. I will see whats up on some pics when the lights come back on tonight. need to do some adjustments anyways. got that co2 burner runnin last night and that dude puts on a serious show with some serious heat. i'm considering an a/c if the heat doesn't go down. but i think the fan is good, it moves a whole lot of air for sure with no signs of struggle or anything. you can see there is some sort of pressure in the room though because my white reflective pvc plastic stuff is ballooning out. updates to come. Thanks again for the help.

[SpaceNeedle]

First thanks to everyone for the replies. Ok I think I am going to attempt an intake. how i have it set now is the carbon filter is on one side of the room, from that comes out ducting then i have a Y splitter for the ducting that goes from one 8" and splits into two 6" for the light hoods. then goes across and the two sets of two lights are connected and the ducting continues to another Y connector that converts my two 6" runs into a single 8" again then that connects to my exhaust fan. I did throw that term sealed room out there loosly because my room has no intake vents an i put in hella work makin sure every inch was sealed up. I will see whats up on some pics when the lights come back on tonight. need to do some adjustments anyways. got that co2 burner runnin last night and that dude puts on a serious show with some serious heat. i'm considering an a/c if the heat doesn't go down. but i think the fan is good, it moves a whole lot of air for sure with no signs of struggle or anything. you can see there is some sort of pressure in the room though because my white reflective pvc plastic stuff is ballooning out. updates to come. Thanks again for the help.

When you have an intake, you have to have an exhaust, and then you don't have a sealed room. Your ambient temp outside your room is probably higher than say, 'normal'. Assuming your room is properly sealed in order to be running CO2, you need to bring the air inside your room, and that will require air conditioning, and you should be able to set the A/C to come on at 85F. 4 600W lights produce 3000 BTUs of heat. I know the lights are vented, but if the air being passed thru starts at being too warm, it will have less effect to keep your room cooler. You will require a 2-3 ton A/C. There's 12,000 BTUs in a ton, so a minimum of 2 large window bangers, as we call them.
I've worked in the HVAC industry for about 10 yrs.

sm

[juggaloscrub]

the air passing through the lights does exhaust. I just do not have an intake. I have a plan for making an intake tonight, I will post with pics and hopefully results. I only need to come down about 10 degrease and i am thinking this may do it. Hopefully. lol

[SpaceNeedle]

What is the ambient air temp around the room and the temp the air is before coming thru the lamps?

for what its worth:

You have no sealed room once you make an intake, and you will have smelly air coming from it.