Tutorial Ventilation 101

[shannonball]

hi everyone, new to this site. came over from Rollitup. We just finished fixing up our shed to grow (legal state of MA). We have a timber lighting 900 watt Vero 29c's LEDs in an 7x4'5" room 8' high.
We are going to install a fresh air intake using a Hepa filter in a filter box on a hurrican 8" inline fan. We will have an exhaust fan in the gable for outtake, no filter required as the smell is not going to be noticed due to no neighbors. We will fans blowing both plants and the heat sinks on the leds. What size exhaust would you recommend and does our setup sound alright and what should we change? thanks shannon

 

[zeke99]

.

 

[Kwigybo]

I'm having real heat issues in my tent and I can't figure out why. Tent is 2'x4'x7' (56 cubic feet). Light is a 400w hps in a cooltube with a 5 inch exhaust fan. It's exhausting through a hole in the floor (one 90 degree bend) and is rated at 165cfm.

Second fan is a 4 inch axial hooked up to a 12inch carbon filter and is rated at 80cfm. And two passive intakes.

Ambient temps are around 68 but after a few hours with the light on it's up to 84 and just keeps climbing.

Any help would be greatly appreciated. Thanks.

 

[Snook]

6" cool tube w 5" fan??

what type of fan is exhausting the light and how far is it from the light to the exhaust hole in the floor and is it pushing or pulling air through the light? Pics would help.

 

[OldPhart]

I'm having real heat issues in my tent and I can't figure out why. Tent is 2'x4'x7' (56 cubic feet). Light is a 400w hps in a cooltube with a 5 inch exhaust fan. It's exhausting through a hole in the floor (one 90 degree bend) and is rated at 165cfm.

Second fan is a 4 inch axial hooked up to a 12inch carbon filter and is rated at 80cfm. And two passive intakes.

Ambient temps are around 68 but after a few hours with the light on it's up to 84 and just keeps climbing.

Any help would be greatly appreciated. Thanks.

I see two issues, as Snook pointed out, the size of the fan/duct on the light sounds suspect. The other issue is the axial fan on the carbon filter. An axial fan isn't well suited to producing static pressure required to move the air through a carbon filter. I wouldn't be surprised if your 80cfm fan is only moving 25cfm with the filter attached. I would be looking to get at least 120cfm (2 air changes/minute) out of the tent. Depending on the efficiency of the cooling of the light, you may be able to reduce this requirement.

I would also insulate as much of the ducting carrying the heat off the lamp as possible.

 

[zeke99]

I'm having real heat issues in my tent and I can't figure out why. Tent is 2'x4'x7' (56 cubic feet). Light is a 400w hps in a cooltube with a 5 inch exhaust fan. It's exhausting through a hole in the floor (one 90 degree bend) and is rated at 165cfm.

Second fan is a 4 inch axial hooked up to a 12inch carbon filter and is rated at 80cfm. And two passive intakes.

Ambient temps are around 68 but after a few hours with the light on it's up to 84 and just keeps climbing.

Any help would be greatly appreciated. Thanks.

FWIW, according to the CF Group (Can-Filter), a single 90 degree bend can reduce the airflow by a few percentage points.

 

[Kwigybo]

Thank you Snook, OldPhart and Zeke for the responses. Much appreciated.

*The cooltube is actually 5" (not 6") so it matches the fan size in diameter.
*The type of fan exhausting the light is a mixflow tt 125 (5"). Link
*The distance from the light to the exhaust hole is roughly 7.5 feet.
*The light exhaust fan is situated about 1 foot above the floor hole and is pulling air through the cooltube/ducting.
*And I'm using 5" insulated ducting.

I think you're right OldPhart that the Allvent axial, though a high quality product, simply isn't designed for the pressure required to work with a carbon filter. I have another axial which is 5inch, so I wonder if I swapped the mixflow to the carbon filter and put the axial as the light exhaust if that would improve the results.

I'll try to get some pictures.

Once again, thank you for your replies.

 

[Snook]

Thank you Snook, OldPhart and Zeke for the responses. Much appreciated.

*The cooltube is actually 5" (not 6") so it matches the fan size in diameter.
*The type of fan exhausting the light is a mixflow tt 125 (5"). Link
*The distance from the light to the exhaust hole is roughly 7.5 feet.
*The light exhaust fan is situated about 1 foot above the floor hole and is pulling air through the cooltube/ducting.
*And I'm using 5" insulated ducting.

I think you're right OldPhart that the Allvent axial, though a high quality product, simply isn't designed for the pressure required to work with a carbon filter. I have another axial which is 5inch, so I wonder if I swapped the mixflow to the carbon filter and put the axial as the light exhaust if that would improve the results.

I'll try to get some pictures.

Once again, thank you for your replies.

5" cool tube, I never noticed a 5" one before but see that 'china' make them. Its hard to screw up a glass tube but if you bought the fans from them too, could be they are less affective than advertised.. we all start out 'el cheapo', so did I but over the years, its become clear to me that that is not always the cheapest way to go because, at least I, had to buy mobetta 'parts' a second time. GL bother.

 

[Ruskointhehouse]

I'm having real heat issues in my tent and I can't figure out why. Tent is 2'x4'x7' (56 cubic feet). Light is a 400w hps in a cooltube with a 5 inch exhaust fan. It's exhausting through a hole in the floor (one 90 degree bend) and is rated at 165cfm.

Second fan is a 4 inch axial hooked up to a 12inch carbon filter and is rated at 80cfm. And two passive intakes.

Ambient temps are around 68 but after a few hours with the light on it's up to 84 and just keeps climbing.

Any help would be greatly appreciated. Thanks.

why are you exhausting via the bottom of the grow? heat rises - vent from the top man.

 

[Granger2]

Forget axials. The do little actual air movement. Good luck. -granger

 

[Kwigybo]

why are you exhausting via the bottom of the grow? heat rises - vent from the top man.

Well the cooltube duct runs parallel across the top and out of the tent, then a 90 degree bend down to the floor hole. I did that cause I can't vent into the floor above as I'm ground level.

 

[Kwigybo]

Forget axials. The do little actual air movement. Good luck. -granger

lol yeah I'm finding that out.

 

[mexicani-ar]

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[FreeUrMind]

I have 18mm Mdf do you think it Would be any good to reduce noise from an 8ins rvk vent fan I have it on a 5 step variac controller on number 1 but fan is too loud

 

[wutwut]

Hey, does TD-silent & TT-silent have any other difference than weight? Which one you recommend to bedroom:
1. Vents TT-silent-M 220/340
2. S&P TD-silent 220/380

 

[FreeUrMind]

Hey, does TD-silent & TT-silent have any other difference than weight? Which one you recommend to bedroom:
1. Vents TT-silent-M 220/340
2. S&P TD-silent 220/380

I was reading on here that the td silent are great fans and guys 200mm
Fan is quiet and his oscalating fan is louder

 

[Guest]

Hey, does TD-silent & TT-silent have any other difference than weight? Which one you recommend to bedroom:
1. Vents TT-silent-M 220/340
2. S&P TD-silent 220/380

I have a smaller TD silent 100 and it's quieter than my tower oscillating fan. They are a bit pricey but worth the stealth to me. There may be quieter but I have not compared.

 

[Xanode]

About a year ago I upgraded my 1x1x2(400w hps) bloom tents ventilation system from:

bodged up pc fans strapped to the tent intake and outtakes, open batwing hood, no filter. Had high temps, high RH and the place of course stank

To:

2x 6-inch hyper fans for intake/outtakes, air cooled hood, standard ducting and carbon filter. All conditions fell into what looked like the right parameters, temps maxed out at 27c and RH never above 65%.

The upgraded ventilation runs like so:

Duct intaking from window to intake fan inside tent via duct, then I have a couple of household fans circulating air inside the tent,

the exhaust is setup like this:

carbon filter and fan attached, fan sucks tent air through filter, pushes it through duct and hood and out some duct, out another window. Pushing the filtered exhaust air through the hood eliminates any smell from escaping from hood and duct air since it's been filtered

I did it in hopes of making life easier, but not so.

Ever since I have had a drop in yield and quality by about 30%, I have tried everything, new bulb, genetics, etc..

Could I be over venting? Although i adjust the fans to run at slight neg pressure, can these be causing some kind of problem?

Thanks for any help.

 

[FredyJohnSmith]

Great post. Can you carbon filter in case you are living in areas where air quality is not that good?

 

[wutwut]

i had 600w hps with td-silent 350 before and my temps were just & just right during lights on. tent size 4x4.

my question: is there much difference in that noise between td-silent 350 vs 500?

i'm planing to buy td 500 but worried about noise and can i sleep with that in my bedroom.

380m3/h (125mm) vs 450m3/h (150mm)