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Exhaust (2) 1000w Cool Tubes - 6" or 8"?

I

Imma Bri

Member
Hi everyone! This is my first post on the path to a grow and I just hit a problem I can't sort out myself.

The problem is: What size fan should i use to move the heat off the lights via the ducting.

I am using an 8 x 8 - grow tent, for a vertical stadium grow.

- 2, 1000w hps 6" Cool Tubes
- 18ft of 6" duct tube which will suck cold air from outside over the bulbs.
- 6 elbows total in the line


The 6" moves 351cfm. The 8" moves 740cfm.


I am concerned that the 351cfm will be insufficient because the ducting has a mandatory: 6 bends.

#1 - Is a 6" inline fan @ 351cfm enough or should i get the 8" @ 740cfm?

#2 - Would a "duct splitter" be a better choice since it reduces the 90 turns to 2 for each light? But the intake is split and I was wondering if that would reduce the flow of air over the bulbs.



The TL;DR version:

- Fan size to use? 6" or 8".
- Duct split or not to split (6 elbows, or 2 elbows and a 2 Y-splitters)
- Length of ducting okay?

Ta for the assistance in advance!

:thank you:
 
I

Imma Bri

Member
St. Phatty said:
I would go for 6 inch and start out with 1 light.

Then measure temps & see how it 'feels'.
Click to expand...

Okay then!

I connected the 6" ducting to the fan with the window vent.

Temps incoming are 10F, the fan pushes the air (had the fan nearest the window) no problem and then air coming past the light was dropping into the 60's.

However, i 'feel' that 351cfm will be slightly under-powered to move the air 16-18ft efficiently enough to help keep cooler ambient temperatures around (2) 1000 bulbs in the tent.

picture.php

View image in gallery​



No idea why it turned side ways. :shucks:

I think an 8" is better suited and will keep more pressure moving the air.

Good news is that the exhaust can actually be plugged back into the tent for cooling because the air is that cool. :dance013:
 
Switcher56

Switcher56

Comfortably numb!
You forgot an important measurement. Height! Can't figure out CFM or CFH without it. So I went with the std 6 foot tent. The formula is: V (volume) x F (factor) x 25 or 30 (exchanges/hr) total amount to move (CFH)

  • you have a total of 384 ft3
  • trunking losses = 768 ft3 (factor of 2, (ducting only))
  • filter/trunking loss = 1152 ft3 (factor of 3, (filter & ducting))
Therefore, your total volume in your room/tent = 1152 ft3. The norm is 25-30 exchanges. Although I have ran across some say up to 60 exchanges/hr. Personally I find that number excessive, as I have to throttle my fan to maintain ambient conditions. I run a 3x3x6ft (162 ft3 (factor of 3)) tent with a 4" 190cfm (11400 CFH). My requirement is:

  • 25 exchanges = 4050 CFH
  • 30 exchanges = 4860 CFH
  • 60 exchanges = 9720 CFH
My fan unencumbered has a capacity of 190 CFM x 60 min/hr = 11400 CFH. More than adequate to do the job.

Since most use a filter, we can readily dismiss the factor 2 and, use factor 3 only:A 350 cfm is capable = 21000 CFH
  • A 740 cfm is capable = 44400 CFH
You require:

  • V = 8'x8'x6 = 384 ft3
  • F3 = 384 x 3 = 1152 ft3
    • 25 exchanges = 28800 CFH
    • 30 exchanges = 34560 CFH
    • 60 exchanges = 69120 CFH
Therefore, since you require to move 34560 CFH and a 8" an has a capacity of 44400 CFH, you would be more than covered. :tiphat:
 
I

Imma Bri

Member
Switcher56 said:
You forgot an important measurement. Height! Can't figure out CFM or CFH without it. So I went with the std 6 foot tent. The formula is: V (volume) x F (factor) x 25 or 30 (exchanges/hr) total amount to move (CFH)

  • you have a total of 384 ft3
  • trunking losses = 768 ft3 (factor of 2, (ducting only))
  • filter/trunking loss = 1152 ft3 (factor of 3, (filter & ducting))
Therefore, your total volume in your room/tent = 1152 ft3. The norm is 25-30 exchanges. Although I have ran across some say up to 60 exchanges/hr. Personally I find that number excessive, as I have to throttle my fan to maintain ambient conditions. I run a 3x3x6ft (162 ft3 (factor of 3)) tent with a 4" 190cfm (11400 CFH). My requirement is:

  • 25 exchanges = 4050 CFH
  • 30 exchanges = 4860 CFH
  • 60 exchanges = 9720 CFH
My fan unencumbered has a capacity of 190 CFM x 60 min/hr = 11400 CFH. More than adequate to do the job.

Since most use a filter, we can readily dismiss the factor 2 and, use factor 3 only:A 350 cfm is capable = 21000 CFH
  • A 740 cfm is capable = 44400 CFH
You require:

  • V = 8'x8'x6 = 384 ft3
  • F3 = 384 x 3 = 1152 ft3
    • 25 exchanges = 28800 CFH
    • 30 exchanges = 34560 CFH
    • 60 exchanges = 69120 CFH
Therefore, since you require to move 34560 CFH and a 8" an has a capacity of 44400 CFH, you would be more than covered. :tiphat:
Click to expand...
With me, numbers are often very numbing. But you did a wonderful job in displaying each variable and how you got the number, and the math definitely dictates what we should do for most optimal results.

Thanks loads for that data! It is a question I will never have to ask again. I have read that Ventilation 101 thread first few posts on 3 different occasions and each time ran away and dove into my bong to clear my head.
 
Switcher56

Switcher56

Comfortably numb!
Imma Bri said:
With me, numbers are often very numbing. But you did a wonderful job in displaying each variable and how you got the number, and the math definitely dictates what we should do for most optimal results.

Thanks loads for that data! It is a question I will never have to ask again. I have read that Ventilation 101 thread first few posts on 3 different occasions and each time ran away and dove into my bong to clear my head.
Click to expand...
LOL U R welcome :)

It took me a while to post my reply, "my hit" was confusing my brain LOL. I created the spread sheet a long time ago. Just had to use your numbers and, a big and, figure out how the formulas worked again. All I do now is simply plug in numbers, the formula does the rest. Did similar for figuring out lights as a quick reference. Excel is our friend :)
 
R

russian420

Member
These Cooltube 6" is not made for 1000w

4" cooltubes 400w
6" cooltubes 600w
8" cooltubes 1000w

Google 1000w HPS Cooltube pictures.
You will notice there is some good ones 8"
These have more space, better socket most times that handle 1000w fine.

Also in security issues. You want 8" cooltubers if you use 1000w.
No matter what, the bulp can even explode in these and still not cause fire.
The small ones can start fire if you use strong HPS.

You need reflectors also. ? YES i think so.
Push the light to plants is important.
You dont want use growlight to light up the roof maybe ?

1000hps needs big respect. Heat is insane.
Try real 8" cooltubes made for these bastards or som better reflectors.

Now you need adjust the light to 600w HPS or buy better bigger cooltubes, or other better reflectors.

Right now you do very wrong.
Sorry say that. HELPING ONLY

GOOD LUCK IN FUTURE
 
R

russian420

Member
long time run.

SAFETY FIRST ALWAYS.

what i mean in the end is:
You got issue with cooling fan.
The 1000hps lights is on with these little cooltubes.

I DONT WANT SLEEP IN YOUR PLACE before you make it better.

Hope this helps you understund better
 
R

russian420

Member
THIS WORKS if the fans works.

The day fan gives up.
I DONT WANT BE THERE

1000W bulbs need huge big safe reflectors if you want survive 100%
 
I

Imma Bri

Member
f-e said:
200mm L1 not A1
Click to expand...

Thank you for the education. I looked that up. :D

I have to call the fan company tomorrow to ask their tech support if its an A1.

The fans are AC Infinity Cloudline.

The 6" is 351 CFM, and the 8" is 740CFM. They also operate at the temps the temps of -10c to 115c, which seems pretty good with the limits i have seen on others, but I have seen very little.
 
I

Imma Bri

Member
russian420 said:
These Cooltube 6" is not made for 1000w

4" cooltubes 400w
6" cooltubes 600w
8" cooltubes 1000w

Google 1000w HPS Cooltube pictures.
You will notice there is some good ones 8"
These have more space, better socket most times that handle 1000w fine.

Also in security issues. You want 8" cooltubers if you use 1000w.
No matter what, the bulp can even explode in these and still not cause fire.
The small ones can start fire if you use strong HPS.

You need reflectors also. ? YES i think so.
Push the light to plants is important.
You dont want use growlight to light up the roof maybe ?

1000hps needs big respect. Heat is insane.
Try real 8" cooltubes made for these bastards or som better reflectors.

Now you need adjust the light to 600w HPS or buy better bigger cooltubes, or other better reflectors.

Right now you do very wrong.
Sorry say that. HELPING ONLY

GOOD LUCK IN FUTURE
Click to expand...

No reflectors on this grow because its vertical stadium style.

The Cool Tube temp tested earlier with about 26c - 30c at just 3-4cm from the Cool Tube with only (1) 6" fan going. So yes, as long as the fans are going everything is fine, and I can use a monitor to turn the lights off with an alarm if temps go above a threshold of perhaps 32c.

And the real life fact part is that I can't replace them with 8" now. But I will be able to next time around if required.

Thankfully I got a free fan from Amazon by their error, so now there can be 2 fans on that line: 8" pulling, and the 6" pushing.

:thank you: Thank you very much for your concern.
 
f-e

f-e

Well-known member
Mentor
Veteran
Imma Bri said:
Thank you for the education. I looked that up. :D

I have to call the fan company tomorrow to ask their tech support if its an A1.

The fans are AC Infinity Cloudline.

The 6" is 351 CFM, and the 8" is 740CFM. They also operate at the temps the temps of -10c to 115c, which seems pretty good with the limits i have seen on others, but I have seen very little.
Click to expand...

They won't know what your talking about. I'm not sure many people would. I looked up your fan though, and it appears to be an axial fan.

There are two types of fan we see all the time. Axial, like found on your desk, and centrifugal, which is used for ducting. Now sat on the table, the axial fan shifts more air. But start asking one to do some work and it falls flat on it's face. The centrifugal fan doesn't shift as much air, but ask that to do some work, and it will.

Some axials have overlapping blades, so will work on simple duct runs. This appears to be what you have. Usually they won't share the graphs of delivery at varied levels of duct resistance. Because there crap. You have a couple of lights and 6 bends, you can't have that. You need a real duct fan in your collection. Forget that peak figure people are seen offering out. Your not getting it. In my youth, I had a 12" £300 expelair axial fan. The dogs it was. I used a big road cone to shrink that 12" down to 4" and it didn't do shit. Wrong fan. It did an entire hospital day room, but not my 4" hole.

Once you move on to proper duct fans, with their centrifugal fans and proper graphs, your buying the right kit. Only then can you talk L1 and A1. A1 is standard power, and L1 high power. An 8" L1 uses the motor from the 10" A1 from the same range usually. And nothing pushes harder. Not the 10 the 12 or the 15. They will shift more air if the duct is big enough, but for most decent fan ranges, it is the 8" L1 that puts the most air through a 6" hole. If someone finds that not to be so, please let me know.

In the UK...about £120


edit: if you don't have all this kit yet, consider a 1000 behind glass is 850. Plus is needs a fan, so it's more like 850 costing 1050. Then look what lamp temp does to colour. If we use the research of others, your 1050 might give 800w while it's still clean. 80% of a 1000 is about 105,000 lumens. A 600 is 90,000. Very quickly a 1000 is eroded into the pensioner of lighting. A 600 lights a meter like the sun. More than some plants can handle. What are you doing with a 1000 ? It seems your 10 years late
 
Last edited:
f-e

f-e

Well-known member
Mentor
Veteran
Russian420. Anybody can make 3 posts on the trot, but you seem to be making a living from it. Why are you racing for 50 posts. I have to presume you were recently banned
 
I

Imma Bri

Member
f-e said:
They won't know what your talking about. I'm not sure many people would. I looked up your fan though, and it appears to be an axial fan.

There are two types of fan we see all the time. Axial, like found on your desk, and centrifugal, which is used for ducting. Now sat on the table, the axial fan shifts more air. But start asking one to do some work and it falls flat on it's face. The centrifugal fan doesn't shift as much air, but ask that to do some work, and it will.

Some axials have overlapping blades, so will work on simple duct runs. This appears to be what you have. Usually they won't share the graphs of delivery at varied levels of duct resistance. Because there crap. You have a couple of lights and 6 bends, you can't have that. You need a real duct fan in your collection. Forget that peak figure people are seen offering out. Your not getting it. In my youth, I had a 12" £300 expelair axial fan. The dogs it was. I used a big road cone to shrink that 12" down to 4" and it didn't do shit. Wrong fan. It did an entire hospital day room, but not my 4" hole.

Once you move on to proper duct fans, with their centrifugal fans and proper graphs, your buying the right kit. Only then can you talk L1 and A1. A1 is standard power, and L1 high power. An 8" L1 uses the motor from the 10" A1 from the same range usually. And nothing pushes harder. Not the 10 the 12 or the 15. They will shift more air if the duct is big enough, but for most decent fan ranges, it is the 8" L1 that puts the most air through a 6" hole. If someone finds that not to be so, please let me know.

In the UK...about £120


edit: if you don't have all this kit yet, consider a 1000 behind glass is 850. Plus is needs a fan, so it's more like 850 costing 1050. Then look what lamp temp does to colour. If we use the research of others, your 1050 might give 800w while it's still clean. 80% of a 1000 is about 105,000 lumens. A 600 is 90,000. Very quickly a 1000 is eroded into the pensioner of lighting. A 600 lights a meter like the sun. More than some plants can handle. What are you doing with a 1000 ? It seems your 10 years late
Click to expand...

I have planned to reduce the 90 degree bends to 2 using a Y-splitter from the intake to both tubes with them exhausting through different ports so they don't need another why and only use 2 bends total each. The 8" should perform to the task.

The ballasts are dimmable to 60%, and that seems a bonus now.

Thanks for the great information!
 
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