2 fans on one duct run?

[apartmentblower]

im running:

can 66 filter ---> 600w cooltube ---> 600w cooltube --> 6" s&p 312cfm exhaust


i havent checked temps yet but i have a feeling that the fan is a bit undersized for this application. i can barely feel the filter sucking in air but then again its got alot of surface area for the size fan im running so maybe its not apparent yet how much its exhausting but for future reference, is it possible for me to throw in another identical fan right after the carbon filter to help keep cfm's up? or is this a waste of money? the fan just barely meets the minimum requirements for the filter so im worried that the big filter is bogging it down too much

im running a pair of the above (4x600w) and this is all im using for exhaust so i really need to make it work. i wish i had bought 8" fans and 8" ducting but the cooltubes were 6" so i assumed 6" would be enough so i stuck with 6" fans and ducting


i have a feeling i might need to throw a portable a/c in the room to keep temps down (PITA)

 

[solarz]

Well, personally, i would just shell the $$ to buy another, properly sized fan. If you are wanting to spend some $$, don't get the same fan, just get a bigger/better one.

on another note, you could grab yourself one of those duct boosters(about $30) to help things along, but i'm not really sure how efficient it is to push air thru those cool tubes.

solarz

 

[FreezerBoy]

I love and adore my S&P but, would only recommend them for those with strong concerns for stealth and spacial economy. They simply can't compete with centrifugals for pulling power.

Sounds like you're growing in a room as opposed to a cab. If that's true, the ear bleeding scream of Vortex and similar can be tamed and contained within the room allowing much greater airflow.

 

[apartmentblower]

alright, i think i will upgrade to 8" fans. will a 8" fan pulling through 6" ductwork (with a reducer) be significantly better? ie. does the reducer cut down cfms alot?

 

[issack]

alright, i think i will upgrade to 8" fans. will a 8" fan pulling through 6" ductwork (with a reducer) be significantly better? ie. does the reducer cut down cfms alot?

Ive had no probs with reducing to 6" ducting from 8" fans.. I've hooked up 3 or more lights on cooltubes and been fine.

 

[solarz]

no problem reducing, i'm currently running a 8in fan reduced to 6in ducting, and i'm pulling thru a DIY carbon filter + lights (1200w) and my temps stay b/w 72-74 lights on.

solarz

 

[RockyMountainHi]

When I was figgurin, I found this set up I figgured would work.





750 CFM can fan on a speed reducer - running about 50-60%

the 8-inch T and 2 8-in to 6-in reducers.

All from Home Depot - (The T fitting and the reducers,,)

And it works great!

Filters on both air intakes on the hoods - air draws thru the hoods into the fan and exhausts into a 15x48" scrubber in an adjacent room.

no more dank smells outside of the grow room.

 

[apartmentblower]

thanks for the info

im going to be updgrading from cooling 2x600w lights with 312cfm 6" to 8" 675cfm (actual cfm is less due to carbon filter and ducting runs but its twice the CFM that matters)

 

[RockyMountainHi]

Dunno about 600's - Twin 1000W hortilux is all I run in flower

 

[apartmentblower]

Dunno about 600's - Twin 1000W hortilux is all I run in flower

lol if your 750cfm at 50% can cool 2x1000w i think a 600cfm~ fan will handle 2x600w not too bad

thx

 

[dotblunt]

I had 2 very very cheap bath fans from Home depot that I linked to run something similar to what you have. Each fan by itself was shit, but I must say I was pleasantly surprised when I ran one on each end in a push pull configuration.

It was a very small 250HPS setup in a closet with 2 50CFM $12 bath fans, but I don't see why it wouldn't scale up.

Dot

 

[phr3d0m2gr0]

To answer two of your questions in order:
1. Yes you can throw another fan of the same size and it will help. Take a look at redgreenry's thread on ventilation, specifically (post #47):

..add a second fan inline with the first. The fan curve is the single fan curve with the pressure doubled at the same flow rate value.

So if you add another fan it will boost your sucking power and pull through the carbon better.

2. You can also use 8" fan and a 6" reducer. The CFM will be the same, but the air speed of the air going from 8" to 6" will increase. It's for this reason I would suggest using 8" ducting if possible because this will reduce ducting noise significantly.

-Phr3

 

[Jnugg]

If you're using a 6" cool tube and have 8" fans I'd use 8" ducting,with a reducer you'll get some back pressure.Also this will help keep things quieter.