CFM Increase Duct Wye Adaptor - 2 Fans

saiyaneye

Well-Known Member
Okay, I am not an artist! :finger:

Lets say I have two 440 CFM fans. One for the carbon filter and one to cool lights going into a Wye Adapter. How will my final CFM be effected for matching CFM with a filter? I forgot to draw a fan for the light.

DSCN1496[1].JPG

And i spelled "adaptor" wrong lol
 
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Budley Doright

Well-Known Member
The filter would be sized for 440. Each branch would be the same and the common discharge would be the sum of both, so 880. This is going to be somewhat lower due to friction loss. Your single pipe should really be like 10" min and that would be noisey. 800 cfm is a lot of air lol.
 

DesertGrow89

Well-Known Member
The filter would be sized for 440. Each branch would be the same and the common discharge would be the sum of both, so 880. This is going to be somewhat lower due to friction loss. Your single pipe should really be like 10" min and that would be noisey. 800 cfm is a lot of air lol.
LOL. Personally I cut the top off of my tent and just blow heat off the fixture before it hits the canopy, works fine. Also happy plants don't stink and carbon filters would be a waste of money IMO. Unless perhaps you are venting outside of the room.
 

saiyaneye

Well-Known Member
LOL. Personally I cut the top off of my tent and just blow heat off the fixture before it hits the canopy, works fine. Also happy plants don't stink and carbon filters would be a waste of money IMO. Unless perhaps you are venting outside of the room.
You vent your lights back into your tent?
 

Flagg420

Well-Known Member
.....get a bigger tent..... or a smaller lighting and vent system.... what are you cooling? I have gotten away with decently cheap bathroom vent fans for exhausting smaller lights...

I dunno, after buying a new 6" filter n still having stank... i just gave up n punched a hole thru the brick to vent outside. Next I will get 8' of 6" stove pipe and a cap, will look like I got a wood burner in the basement that never gets used.... stink is released @ or above roof level :)

And... happy plants DO stink... during the last week while flushing :) and in a perpetual.... thats pretty much always, lol.
 

bryangtho

Well-Known Member
The problem I see there is that you blowing the hot air back to the wye adapter. And then you will drag the hot air back down to your light
 

saiyaneye

Well-Known Member
The problem I see there is that you blowing the hot air back to the wye adapter. And then you will drag the hot air back down to your light
Wye adaptors are made for optimal airflow to the outlet...

.....get a bigger tent..... or a smaller lighting and vent system.... what are you cooling? I have gotten away with decently cheap bathroom vent fans for exhausting smaller lights...

I dunno, after buying a new 6" filter n still having stank... i just gave up n punched a hole thru the brick to vent outside. Next I will get 8' of 6" stove pipe and a cap, will look like I got a wood burner in the basement that never gets used.... stink is released @ or above roof level :)

And... happy plants DO stink... during the last week while flushing :) and in a perpetual.... thats pretty much always, lol.
My carbon filter in my current setup works great....

The picture is just a representation of a room. Like i said, i am not an artist. I can't get a bigger room... I will be running two 400w lights.
 

Flagg420

Well-Known Member
The problem I see there is that you blowing the hot air back to the wye adapter. And then you will drag the hot air back down to your light
He didn't show it in the pic, but theres 2 fans.... may need a backflow flapper tho just to act as a check valve....


I run two sun system 315w LECs in an open tent, no venting needed, just a fan..
Them gotta hang/mount vertical? Special ballast or 400w mag style?
 

Honey Oil Riot Squad

Well-Known Member
Okay, I am not an artist! :finger:

Lets say I have two 440 CFM fans. One for the carbon filter and one to cool lights going into a Wye Adapter. How will my final CFM be effected for matching CFM with a filter? I forgot to draw a fan for the light.

View attachment 3627681

And i spelled "adaptor" wrong lol
A lot of what people are saying is NOT neccesarily true. To truly give you an accurate answer I'd need to know the dimensions of all of your ducting.
I'm going to assume its all the same diameter everywhere...
Also I'm going to assume the second fan is pushing air behind the light... you should label that.

Fluid dynamics says that combining the two pathways that BOTH have air in them would actually be less effective due to the added pressure in the y valve or whatever it's called where they connect. The added pressure causes need for higher velocity of the air at the end of the y valve which creates more resistance for the fans to be working against. I.E. THIS MEANS if ANYTHING, combining the two pathways would SLOW THE AIR FLOW down.

It would not double it to 880 CFM. The total CFM would be somewhere in between that and 440.
If you were to have two totally separate lines running the total would be 880, or if the diameter at the end of the y valve was much bigger it would be 880.

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saiyaneye

Well-Known Member
dumb question....do you have the fan before or after the light. I can see the fan motor getting really hot from the lights if it is after.

6x6x6 wye (something weird :p)?
or
8x6x6 wye<---880 (approx)?
 

Honey Oil Riot Squad

Well-Known Member
dumb question....do you have the fan before or after the light. I can see the fan motor getting really hot from the lights if it is after.

6x6x6 wye (something weird :p)?
or
8x6x6 wye<---880 (approx)?
I have it before. I'd agree tho I've never thought of that glad I didn't put it after lol.

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Honey Oil Riot Squad

Well-Known Member
The filter would be sized for 440. Each branch would be the same and the common discharge would be the sum of both, so 880. This is going to be somewhat lower due to friction loss. Your single pipe should really be like 10" min and that would be noisey. 800 cfm is a lot of air lol.
Lolol you changed it yes.


but it's not friction...


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Honey Oil Riot Squad

Well-Known Member
dumb question....do you have the fan before or after the light. I can see the fan motor getting really hot from the lights if it is after.

6x6x6 wye (something weird :p)?
or
8x6x6 wye<---880 (approx)?
8x6x6 would help at least. Let me look up this equation...

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Honey Oil Riot Squad

Well-Known Member
1457605903072.jpg

The exact effect the increase in pressure will have on pushing against the fans is impossible to Calc, but the pressure would decay exponentially (or logarithmicaly I guess) as you increase the diameter of the end of the wye valve or what you seem to call the ;p emoji inappropriately placed next to the balls of the penis emoji. Real mature.
That is until it hits equilibrium to that of in the tube before the y valve.

Anyways the effect of increasing the diameter at the end of the ;p8===D valve will help air flow at an exponential rate, so 8x6x6 would probly be a big help. Might make it negligible. 10 would for sure do it. 880 CFM is a lot of air.

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Budley Doright

Well-Known Member
Huh lol. I'm so confused lol. An 8" pipe would be very restricted, and yes it is friction loss as well as static pressure going way up but thought I'd keep it simple as its going to be approximately 800 cfm. 8" pipe would be around 2000 FPM so yup loud :0. I would just run separate runs I think or try just one fan to start and see if you can keep temps down. And yes it's more efficient to keep the fan upstream of the light due to heat.
 

saiyaneye

Well-Known Member
So i could probabaly get a 750cfm rated carbon filter for my small ass room with the 8x6x6 and be fine? Roughly :p?
 

saiyaneye

Well-Known Member
I may just do that, I am downsizing my room but having the same amount of light. Going from 4x4 to 2x4 I know CFM is WAY overkill.
 
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