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My fan isn't cutting it

TedeBoy

TedeBoy

Well-Known Member
I have a 4" Vortex fan 172 cfm.
My space is about 49 sq ft.
I have tried both T5HO (2-2'x4 bulb fixtures) and a Mars 900w LED fixture. Both produce too much heat for that fan to keep up with effectively. This is even without a carbon filter.
I'm running about 20 feet of ducting which has about 3 bends in it.
What can I do? Get a bigger fan? My ducting runs through drywall so I'd like to stay with 4". Would a bigger fan, reduced down, work?
 
mike4c4

mike4c4

Well-Known Member
TedeBoy said:
I have a 4" Vortex fan 172 cfm.
My space is about 49 sq ft.
I have tried both T5HO (2-2'x4 bulb fixtures) and a Mars 900w LED fixture. Both produce too much heat for that fan to keep up with effectively. This is even without a carbon filter.
I'm running about 20 feet of ducting which has about 3 bends in it.
What can I do? Get a bigger fan? My ducting runs through drywall so I'd like to stay with 4". Would a bigger fan, reduced down, work?
Click to expand...
why 20ft of ducting? That long of a run and only 4' your have a very hard time getting any fan to move enough air. Can you take a pic of your setup, there might be another way to run it.
 
A

anzohaze

Well-Known Member
Either upgrade to bigger fans ducting etc or use 2 4 inch fan a pusher and puller. Install 1 on each end and see if thr helps. Of Not Upgrade 4 I NC Fans I No They Make Bigger Then What YOU Stated
 
Blue brother

Blue brother

Well-Known Member
When it comes to that much ducting and bends airflow goes out the window, it's all about air pressure. If you really can't budge on fan diameter then you need to add more fans Inline to boost the pressure within the duct. Like someone allready said 1 pushing 1 pulling, if that still don't cut it then u want one in between those two. It's a sad situation to have your ventilation dictating what lights you can use. I would really consider making a bigger hole and upping your diameters. But it's up to u at the end of the day bro, if u can't u can't. Hope this helps
 
TedeBoy

TedeBoy

Well-Known Member
Blue brother said:
When it comes to that much ducting and bends airflow goes out the window, it's all about air pressure. If you really can't budge on fan diameter then you need to add more fans Inline to boost the pressure within the duct. Like someone allready said 1 pushing 1 pulling, if that still don't cut it then u want one in between those two. It's a sad situation to have your ventilation dictating what lights you can use. I would really consider making a bigger hole and upping your diameters. But it's up to u at the end of the day bro, if u can't u can't. Hope this helps
Click to expand...
Yeah I messed up. A rookie mistake that's gonna cost me. First I started with that little TD100 fan thinking that would work, then I bought the Vortex, now I will probably need to up my diameter and get another Phresh filter. This is an expensive mistake as I will have to sell my barely used fans and filters at a loss. Oh well, I learned.
 
Blue brother

Blue brother

Well-Known Member
I allwAys say, oversize ur ventilation and if it's too powerful you can dial it down with a fan speed controller. I buy reasonably priced generic centrifugal blowers and replace as needed, whatever I save by buying cheaper fans I spend on a fan speed controller.
 
TedeBoy

TedeBoy

Well-Known Member
Blue brother said:
I allwAys say, oversize ur ventilation and if it's too powerful you can dial it down with a fan speed controller. I buy reasonably priced generic centrifugal blowers and replace as needed, whatever I save by buying cheaper fans I spend on a fan speed controller.
Click to expand...
Thanks. Any recomendations on fans and filters as far as good price?
 
Blue brother

Blue brother

Well-Known Member
TedeBoy said:
Thanks everyone.

I'm really leaning towards upping my diameter from 4 to 6" and getting the Vortex VTX600 with it's 449 CFM and selling my VTX400 172 CFM fan.

Considering my setup would this be enough flow?

https://www.hydroponics.net/i/131323
Click to expand...
It really is hard to say as I don't know what the air temps area and there isn't an exact science to ventilation, atleast not in my experience. There's so many variables, for example rigid ducting is much more efficient than flexible, different brands of carbon filter cause different ammounts of resistance. These are just a couple, u want my advice? whatever cfm u think u need double it, and get a cheap controller (like a light dimmer but for a fan) and start at the fans max output and dial it down until u reach the desired amount of flow.
 
TedeBoy

TedeBoy

Well-Known Member
Blue brother said:
It really is hard to say as I don't know what the air temps area and there isn't an exact science to ventilation, atleast not in my experience. There's so many variables, for example rigid ducting is much more efficient than flexible, different brands of carbon filter cause different ammounts of resistance. These are just a couple, u want my advice? whatever cfm u think u need double it, and get a cheap controller (like a light dimmer but for a fan) and start at the fans max output and dial it down until u reach the desired amount of flow.
Click to expand...
Suppose there were no air restrictions. Do you know what CFM fan would be needed for about 50 cubic square feet? I thought 172 CFM would do it but I guess with all the ducting it's getting cut way down.

I have a plan to shorten the ducting run and use a stiffer walled ducting. If that doesn't cut it I'm upsizing.
 
Blue brother

Blue brother

Well-Known Member
If you want quality and high output you can't beat can max fans Imo. If you want low noise and quality then s&p silent are my favourites.
 
Blue brother

Blue brother

Well-Known Member
If there were no restrictions then 171cfm would do a full rom air exchange in just under 20 seconds, unless your bulbs can heat up your room too much in less than 20 seconds then this would be fine yes. But what u also gotta remember is that your air intake whether passive or active will never allow you to reach that 171 cfm whilst still maintain negative pressure.
 
TedeBoy

TedeBoy

Well-Known Member
Blue brother said:
If there were no restrictions then 171cfm would do a full rom air exchange in just under 20 seconds, unless your bulbs can heat up your room too much in less than 20 seconds then this would be fine yes. But what u also gotta remember is that your air intake whether passive or active will never allow you to reach that 171 cfm whilst still maintain negative pressure.
Click to expand...
I didn't realize the intake restricted like that. Do you know what percentage on a passive intake? I know that adding that booster fan helped but I'm going to rework the ducting now. Just got back from the hardware store.
 
TedeBoy

TedeBoy

Well-Known Member
I think this is working.

Preliminary tests with plants in the grow area and my Mars Hydro 900W LED lamp running.

  • Ambient room temps and humidity - 73.5F and 60%
  • Grow room after 20 minutes - 77.2F and 62%
Is that a reasonable temp difference?
I'm still running the booster fan.

Heres what I did.
 
mike4c4

mike4c4

Well-Known Member
TedeBoy said:
I think this is working.

Preliminary tests with plants in the grow area and my Mars Hydro 900W LED lamp running.

  • Ambient room temps and humidity - 73.5F and 60%
  • Grow room after 20 minutes - 77.2F and 62%
Is that a reasonable temp difference?
I'm still running the booster fan.

Heres what I did.
Click to expand...
There you go.
 
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