New project, 8X8, 4kW..Need Filter/Fan input.

Hello all,

On to my next adventure and my first 4kW setup. I've done plenty 3kW setups, but now I am going to try and maintain a 4kW setup, air cooled(from outside and back outside) with a exhaust/intake fan kicking in to cool when necessary. I think it wouldn't be much of an issue as temps already are at 17-20C, and getting colder. I plan to run everything at night as well where temps will dip nto the 8-12C ranges so it should be easier. Anyone with 4kW experience and cooling it, please fill in your knoweledge!

What I am confused about..My last grow had a lot of positive pressure. I did a sealed CO2, with a re-circulating scrubber. Problem is, towards the last weeks the smell became a big issue and seemed very hard to control. I was using a 6" fan/scrubber combo that matched the cubic print of the room and was suppose to scrub it once per a minute. Not only that, would a 6" fan for intake and another 6" for exhaust be enough to vent heat?(440CFM)

Main questions and summary of post:
Can it be because of positive pressure that a scrubber doesn't work efficiently?
Would I have to upgrade to a bigger filter/fan combo from my 440CFM fan?
Would 6" fans be enough for exhaust/intake or should I get 1 8" for exhaust, and 1 6" for intake?

Dimensions of the room are 8x8x6.5 = 416CF.

ok

first off what hood system are u using ............open reflectors or cool tube system (sealed with air passing over bulb)


ok if u are running 4k i am assuming u mean 4 1000w hids

cooling this is a bitch u will need 3 fans cooltube system and ducting
u get 1 6inch 440 fan and run 2 cooltubes i will tell u how i would do this
ejection point to outside ........ducting.........cool tube....ducting.....fan...ducting...cooltube......ducting intake from a 2nd room
repeat this with the 2nd row

the 3rd fan will be a 8inch matched with a carbon scrubber ,,,,,,,,,,this is the only one need a scrubber this is the exhaust for your grow room ,,,,,,,,u should now have negitive pressure along with a cooler room

edit ........to keep your room cooler .....use insulted ducting for the cooltube it will keep the heat from bleeding out in the room from the ducting 10f degree drop in heat at least

justugh said:

ok

first off what hood system are u using ............open reflectors or cool tube system (sealed with air passing over bulb)


ok if u are running 4k i am assuming u mean 4 1000w hids

cooling this is a bitch u will need 3 fans cooltube system and ducting
u get 1 6inch 440 fan and run 2 cooltubes i will tell u how i would do this
ejection point to outside ........ducting.........cool tube....ducting.....fan...ducting...cooltube......ducting intake from a 2nd room
repeat this with the 2nd row

the 3rd fan will be a 8inch matched with a carbon scrubber ,,,,,,,,,,this is the only one need a scrubber this is the exhaust for your grow room ,,,,,,,,u should now have negitive pressure along with a cooler room

edit ........to keep your room cooler .....use insulted ducting for the cooltube it will keep the heat from bleeding out in the room from the ducting 10f degree drop in heat at least

Click to expand...

I'll be using 4 hoods. Could I run it like ,... Outside > fan > cool > duct > cooltube > duct (U loop) > cooltube > duct > cooltube > fan > back outside?

I want to leave a re-circulating scrubber because I do plan on injecting CO2 here and there.

What do you think? I only want the fans to cool the place, once it's a desired temp then CO2 kicks in before temps go back up. Bad idea or good? Will it work or is it better to just have constant in-take/exhaust?

ajeezy2012 said:

I'll be using 4 hoods. Could I run it like ,... Outside > fan > cool > duct > cooltube > duct (U loop) > cooltube > duct > cooltube > fan > back outside?

I want to leave a re-circulating scrubber because I do plan on injecting CO2 here and there.

What do you think? I only want the fans to cool the place, once it's a desired temp then CO2 kicks in before temps go back up. Bad idea or good? Will it work or is it better to just have constant in-take/exhaust?

Click to expand...

your method will not work..............4 1000w hids would make the air to hot ..............most of the fans have a temp cut off range of 130 to 140 degrees (they will just cut power to self and stop running)

the method i told u it is only sucking over one of the cooltubes and then blowing over the other in the line so the heat will not effect the fan this way


as for what u are talking about with Co2 .............u know Co2 is a heavier gas so aslong as the room is sealed it will fill up like a pond or lake .......then build up until it gets near your ejection point then sent out ...........u just need a fan or 2 inside that moves around to make air currents to move the co2 around ..............and u do know Co2 is only used when the lights are on in the area.......lights on Co2 lights off Oxygen

ajeezy2012 said:

Hello all,

On to my next adventure and my first 4kW setup. I've done plenty 3kW setups, but now I am going to try and maintain a 4kW setup, air cooled(from outside and back outside) with a exhaust/intake fan kicking in to cool when necessary. I think it wouldn't be much of an issue as temps already are at 17-20C, and getting colder. I plan to run everything at night as well where temps will dip nto the 8-12C ranges so it should be easier. Anyone with 4kW experience and cooling it, please fill in your knoweledge!

What I am confused about..My last grow had a lot of positive pressure. I did a sealed CO2, with a re-circulating scrubber. Problem is, towards the last weeks the smell became a big issue and seemed very hard to control. I was using a 6" fan/scrubber combo that matched the cubic print of the room and was suppose to scrub it once per a minute. Not only that, would a 6" fan for intake and another 6" for exhaust be enough to vent heat?(440CFM)

Main questions and summary of post:
Can it be because of positive pressure that a scrubber doesn't work efficiently?
Would I have to upgrade to a bigger filter/fan combo from my 440CFM fan?
Would 6" fans be enough for exhaust/intake or should I get 1 8" for exhaust, and 1 6" for intake?

Dimensions of the room are 8x8x6.5 = 416CF.

Click to expand...

For exhaust: Go with a Phresh or Phat brand filter 8"x39". The filter is rated up to 950cfm if i remember correctly. Use the biggest cfm 8" inline fan you can find(within reason), to try and get close to the 950cfm rating on the filter.
Use one of your 6" inline fans for intake.
By you air-cooling your hoods with separate(from growroom) air, and the temps where you're at, it will work killer.
Only potential problem, is that if the air from outside, that your using to cool the hoods with, is too cold, dripping condensation can happen from your hoods. Especially if your room is 50% humidity or higher.

Aeroknow said:

For exhaust: Go with a Phresh or Phat brand filter 8"x39". The filter is rated up to 950cfm if i remember correctly. Use the biggest cfm 8" inline fan you can find(within reason), to try and get close to the 950cfm rating on the filter.
Use one of your 6" inline fans for intake.
By you air-cooling your hoods with separate(from growroom) air, and the temps where you're at, it will work killer.
Only potential problem, is that if the air from outside, that your using to cool the hoods with, is too cold, dripping condensation can happen from your hoods. Especially if your room is 50% humidity or higher.

Click to expand...

What about exhaust? Or do you mean I should set up the 8" fan/filter as exhaust instead of re-circulating?
I think you're right, 6" is more than enough for intake. I'm just trying to figure out if 2x 6" fans will be enough to cool 4k lights.

The air that will be used will be outside the room, not outside air. However ambient air is only 15-18C(currently till it gets colder). I'd be dragging air from outside to my intake. From what I understand, than a 8" fan/filter for exhaust. Correct me if I'm wrong.

On a side note, would I really need a 8" filter? a 6" would suffice? I am thinking it wasn't working that well because of the positive pressure, I would assume now with an exhaust that mitigates the positive pressure into negative pressure would help the 6" filter. Again correct me with your inputs!

Thanks guys

ajeezy2012 said:

What about exhaust? Or do you mean I should set up the 8" fan/filter as exhaust instead of re-circulating?
I think you're right, 6" is more than enough for intake. I'm just trying to figure out if 2x 6" fans will be enough to cool 4k lights.

The air that will be used will be outside the room, not outside air. However ambient air is only 15-18C(currently till it gets colder). I'd be dragging air from outside to my intake. From what I understand, than a 8" fan/filter for exhaust. Correct me if I'm wrong.

On a side note, would I really need a 8" filter? a 6" would suffice? I am thinking it wasn't working that well because of the positive pressure, I would assume now with an exhaust that mitigates the positive pressure into negative pressure would help the 6" filter. Again correct me with your inputs!

Thanks guys

Click to expand...

K, if you use a 6" for intake, and the same 6" fan w/filter for exhaust, you will have positive pressure(the filter will slow down the fan a smidge).
You want more cfm on exhaust, than what the intake is for negative pressure.
You could slow down the 6" intake fan to acheive this. But since you want to add Co2 while ventilation is off, I would go 8" out/6"in, in order to have more "off ventilation" times.
Make sense?

Aeroknow said:

K, if you use a 6" for intake, and the same 6" fan w/filter for exhaust, you will have positive pressure(the filter will slow down the fan a smidge).
You want more cfm on exhaust, than what the intake is for negative pressure.
You could slow down the 6" intake fan to acheive this. But since you want to add Co2 while ventilation is off, I would go 8" out/6"in, in order to have more "off ventilation" times.
Make sense?

Click to expand...

Perfect sense,

You just answered most questions but, I was thinking if I had the filter re-circulating with it's own 6" fan, and then ANOTHER 6" for exhaust. Still positive pressure? I hear you about having more "off ventilation" times, but that's not much of a concern as much as the smell getting out. CO2 won't be anything I would be using concretely, just a boost till fan kicks in 4-5 minutes later.

What if I use a 8" just for exhaust, and kept my 6" filter/fan for recirculating scrubbing? Still positive pressure? When no fans are on, it's just the filter sucking air(negative pressure) and with the fans running( 6" Intake/ 8" Outtake), the 8" would cause a negative pressure. Correct me if I am wrong, but mainly I am worried about smell getting out. If the 6" filter can handle 410CF, then I don't want to waste $500 on a new filter/fan. I'm just worried that even though I'll have negative pressure this grow, that smell might still leak.

Last time it leaked because I had A LOT of positive pressure(Intake fan and AC). I know I'll need a 8" fan regardless, I just don't want to upgrade the filter if I don't need to. I see plenty of people using a 6" filter for 4kW-6kW setups. Correct me if I am wrong.

Thanks for the replies guys.

ajeezy2012 said:

I know I'll need a 8" fan regardless, I just don't want to upgrade the filter if I don't need to. I see plenty of people using a 6" filter for 4kW-6kW setups. Correct me if I am wrong.

Click to expand...

Ok, so you understand that you need a filter on the exhaust fan rite?
Unfortunately(for your wallet), the charcoal filter needs to be rated a higher cfm, then that of the 8" fan used, in order to work.

And, unless you live in the Arctic, I would not atempt to cool a 4kW-6kW with a 6" exhaust
I've setup an 8" (highest cfm 8" i can find usually) for exhaust with 3kW-4kW many times. If one was to use more than 4kW, an even larger fan/filter is needed(or more cfm). Unless you live in a year round cold climate

Aeroknow said:

Ok, so you understand that you need a filter on the exhaust fan rite?
Unfortunately(for your wallet), the charcoal filter needs to be rated a higher cfm, then that of the 8" fan used, in order to work.

And, unless you live in the Arctic, I would not atempt to cool a 4kW-6kW with a 6" exhaust
I've setup an 8" (highest cfm 8" i can find usually) for exhaust with 3kW-4kW many times. If one was to use more than 4kW, an even larger fan/filter is needed(or more cfm). Unless you live in a year round cold climate

Click to expand...

Ya, but I'm saying..The 8" will be the exhaust, and the 6"fan will be on the filter running 24/7 re-circulating.

i run 5k in a row with no problem and they are on 6 inch hoods but there is also a 10" max fan just over 1000cfms on the other side

are you exhausting out the room?

it seems your room has more issues then a stripper working the day shift on a Tuesday

ajeezy2012 said:

Ya, but I'm saying..The 8" will be the exhaust, and the 6"fan will be on the filter running 24/7 re-circulating.

Click to expand...

If I understand you correctly: you are thinking you can use the 6" fan/filter combo as a scrubber, and not need a filter on the exhaust? If so, your wrong. You WILL STILL need a filter on the exhaust Period.

Aeroknow said:

If I understand you correctly: you are thinking you can use the 6" fan/filter combo as a scrubber, and not need a filter on the exhaust? If so, your wrong. You WILL STILL need a filter on the exhaust Period.

Click to expand...

You understood me perfectly.

Now, why?

Twitch. said:

i run 5k in a row with no problem and they are on 6 inch hoods but there is also a 10" max fan just over 1000cfms on the other side

Click to expand...

You use a scrubber running 24/7 separately from the exhaust? If so, what size scrubber and what size exhaust you use? I'm assuming you mean both the 6" and 10" are exhausting the hoods, correct? What about the other two(room exhaust/filter)? Thanks buddy.

Twitch. said:

are you exhausting out the room?

it seems your room has more issues then a stripper working the day shift on a Tuesday

Click to expand...

The rooms not even running, just getting prepared before hand. You know what though, I have just come to conclusion that I'll stick the 14kBTU A/C in there as well. It kept my temps perfect. I'm not worried for heat as I am worried for smell.

I just want to be able to know that the 6" filter/fan that will be running 24/7 will be enough to hold down the room. I'm only paranoid it won't because my last grow had a in-take that was causing too much positive pressure and smell was leaking. I want to know if I ADD a exhaust now, will the smell stay within the grow room or will it still leak now that I have a negative pressure? I don't mind if it leaks OUTSIDE with the exhaust because I'm sure the amount of smell would disperse immediately because I am about 20 stories high, I'm guessing. Getting into the living space/hallways, is not what I want.

So far great replies and thanks to everyone who did, appreciate the help!

ajeezy2012 said:

You understood me perfectly.

Now, why?



You use a scrubber running 24/7 separately from the exhaust? If so, what size scrubber and what size exhaust you use? I'm assuming you mean both the 6" and 10" are exhausting the hoods, correct? What about the other two(room exhaust/filter)? Thanks buddy.



The rooms not even running, just getting prepared before hand. You know what though, I have just come to conclusion that I'll stick the 14kBTU A/C in there as well. It kept my temps perfect. I'm not worried for heat as I am worried for smell.

I just want to be able to know that the 6" filter/fan that will be running 24/7 will be enough to hold down the room. I'm only paranoid it won't because my last grow had a in-take that was causing too much positive pressure and smell was leaking. I want to know if I ADD a exhaust now, will the smell stay within the grow room or will it still leak now that I have a negative pressure? I don't mind if it leaks OUTSIDE with the exhaust because I'm sure the amount of smell would disperse immediately because I am about 20 stories high, I'm guessing. Getting into the living space/hallways, is not what I want.

So far great replies and thanks to everyone who did, appreciate the help!

Click to expand...

You could have a much, much bigger fan/filter as a scrubber in your room, and not be able to count on it removing all the stink while exhaust fan is actually exhausting air. It just will not.

I do like your idea of having a scrubber within the growroom, just to HELP when ventilation is off. I would also recomend that you put a damper on the intake ducting. Along with a filter ON THE EXHAUST(lol), you will not have any stink escaping the growroom.

I use a can 100 with a 10"max fan, i would recommend atleast one can 100 and 10 max fan for a 4k room for your room, and if you are exhausting out of the room it is not sealed and any CO2 generator you use will be wasted.

also i suck outside air in and push that out the other side, i use a CO2 burner.

Twitch. said:

i would recommend atleast one can 100 and 10 max fan for a 4k room for your room

Click to expand...

ajeezy2012 said:

I think it wouldn't be much of an issue as temps already are at 17-20C, and getting colder. I plan to run everything at night as well where temps will dip nto the 8-12C ranges

Click to expand...

Aeroknow said:

For exhaust: Go with a Phresh or Phat brand filter 8"x39". The filter is rated up to 950cfm if i remember correctly. Use the biggest cfm 8" inline fan you can find(within reason), to try and get close to the 950cfm rating on the filter.
Use one of your 6" inline fans for intake.
By you air-cooling your hoods with separate(from growroom) air, and the temps where you're at, it will work killer.
Only potential problem, is that if the air from outside, that your using to cool the hoods with, is too cold, dripping condensation can happen from your hoods. Especially if your room is 50% humidity or higher.

Click to expand...

You guys are the best, thank you!