Fans, Blowers, Carbon Filters, and Air Cooled Lights

[candyman2007]

I have a few questions about Fans, Blowers, Carbon Filters, and Air Cooled Lights.

I am constructing my first room and I am working on the ventilation at the moment. I would like to get some help, what I have done so far is not working very well.

Current Ventilation setup:
8" Fresh air supply coming from a conditioned area of the house, about a 20 foot straight shot with no bends or curves, it runs to the floor of my grow room.

I have an ECO 435 CFM cage fan connected to a duct box sucking air through the box. On the other side of the box I have 3 6" inlets 2 of which have 6" inline booster fans. One line with a booster goes to the carbon filter, the other goes to an air cooled light. The 3rd line runs to another air cooled light. The air cooled lights pull air from just above the room which is an unconditioned space other than the expelled air from the ECO fan. This way the air going through the lights doesn't pick up an odor.

I feel no air flow coming through the 8" inlet the room is 4x7x8. All the runs other than the 8" are shorter than 6 feet with almost no bends. The lights run pretty cool about 85 before the fans they would get to 97.

Room temp still gets to about 92-93 on hot days

I am thinking about putting the carbon filter on its own 6" Inline Centrifugal fan that way it would pull more air out of the room, thus hopefully pulling more in.

I would love any and all ideas or insight about this issue.

I would also love to hear feedback on what 6" Inline Centrifugal fans people have tried and liked. It seams that you can get one from $89-$299 that is rated at 440CFM. $89 sounds great but I real didn't want to have to buy this second fan and I don’t want to go cheap and get put in another pinch.

[DizzzyLizzy]

Draw a picture. They tell a thousand words....

[candyman2007]

I would also love to hear feedback on what 6" Inline Centrifugal fans people have tried and liked. It seams that you can get one from $89-$299 that is rated at 440CFM. $89 sounds great but I real didn't want to have to buy this twice.

[candyman2007]

Thanks for the reply, so you like the Vortex fans, do you think they where worth the cost over the cheaper guys?


I tired to draw this out but it just ends up looking a mess i might be able to get the wife to draw it.

[candyman2007]

hope this helps.

[DizzzyLizzy]

That drawing will work. First, remember hot air rises and cold air falls. Second, not all fans are created equal.

Fan Basics: Fans are rated by Cubic Feet per Minute (CFM) at different static pressures. Static pressure is typically measured in Inches of Water. A typical a/c duct system in a house is designed to stay below .5 inches of water (think not a whole lot of pressure) in order to keep sound (whistling through registers) at a minimum.

The vortex fans are a type of centrifugal fan. These fans tend to move alot of air against relatively high static pressures. They are rated at zero static pressure meaning no ducting. When you attach ducting to fans, the cfm goes down very quickly and the static pressure rises. The inline duct fans don't move alot of air and won't overcome much pressure. For this application they are not much use. Get rid of them.

From what I see from your diagram and verbal description, you are trying to solve two problems. (1) heat removal & (2) odor control. Lets divide these issues.

First the heat:

Because hot air rises, you want to draw the hottest air out of the room from off of the ceiling. Your cold air inlet should be as far away from the exhaust as possible and should be as high in the room as possible. Remember, the cold air will fall and you want it to fall through the hot air cooling it on its way to the floor. If you duct straight to the floor, the cold air will just stay there will resist your air movement efforts. You may want to put an oscillating fan in the room to mix things up a bit and get the cold air distributed. If you put your cold air supply on the opposite side of the room as your hot air exhaust you will get the most effect. If your cold air inlet is too near your exhaust you will just suck out the cold air with little effective cooling.

Next, lets talk about fan placement. If you want your fans to last don't blow hot air through them. Let them blow through the lights rather than sucking hot air into them. Next, trying to cool a light with hot air from an unconditioned space may not work. Ie. If you are sucking hot air out of your attic and blowing it through your hot light you are probably introducing extra heat into the system. If possible use conditioned air through your lights and put your fans on the cold air inlet rather than your hot air outlet. Your fans will last much longer.

The collection box probably won't work because it is not possible to balance the incoming and outgoing pressures without alot of hassle and if you have a fan failure you could potentially put odor where you don't want it or worse put heat and odor where you don't want them. I would not use the collection box.

Duct each light separately with its own fan then if a fan fails you don't put both lights at risk. Also, put your carbon filter on a centrifugal fan that can over come the resistance of the filter. Carbon filters are hard to push air through or conversly, draw air through. You need a fan that is able to over come both the resistance of the filter and also the resistance in the duct.

I have a couple of questions: How many watts of light?

What is the duct size on the lights? Where does the collection box vent? (hopefully outside)

Any chance you could put a duct fan in the 8" inlet? (an 8" flex duct will move 230cfm @ .3 inches of water static pressure meaning depending on where in the house system you tied into, you may not have enough pressure in the supply duct to adequately push air through this 20' x 8" piece of ducting.

I hope this helps. I apologize if it is too confusing. Let me know if you have additional questions.

[Smokeyjoe]

I visited a friends new flower room yesterday and he had what must have been a 16" exhaust running. I was to scared to get close enough to measure it but I think I could have put my whole 6" through the intake opening lol. Off topic but what they hell had to tell someone!

[DizzzyLizzy]

Check out this thread for fan discussion...

Has anyone used this fan Valueline 6 Inch Centrifugal Inline Fan? - International Cannagraphic Magazine Forums

Dizzzy

[candyman2007]

dizzy I can not say how thankful I am for that information. I feel way better about buying one of this valueline fans. It fustrates me to no end that now it is hot as $h!t in my attic and I have redo all this as I did this all when it was still cool outside. Guess I am going to work on it at like 6 am before it gets so fing hot up there.

[candyman2007]

+reps for DL

[DizzzyLizzy]

Glad to help. When I do attic work it is usually early (4am). Attics are dark anyway so no use working in the heat too. Good Luck!

[Wickedrebel]

If i have a 6x6x8 room and need to run a carbon filter. Can i get a Y duct splitter and pull air through my light on one side and the carbon filter on the other. Would a 6" inline work for this room? how strong of a fan should i get? Thanks for any help

[candyman2007]

Originally Posted by Wickedrebel

If i have a 6x6x8 room and need to run a carbon filter. Can i get a Y duct splitter and pull air through my light on one side and the carbon filter on the other. Would a 6" inline work for this room? how strong of a fan should i get? Thanks for any help

good question.

Wicked i would say if i have learned one thing in the construction of my ventilation system is the more air flow the better. I would say if you only have the one light and one fan the best application would be to go filter then fan then light then duct out of the room. that way all the air that expels out of the room has been pulled through the carbon filter "cleaning the air" then pushing the air through the light "less heat pulled through the fan the longer the fan will last" then vent all the air out of room so that over all room cooling is achieved. hope this helps

CM

[candyman2007]

One thing I have found is that the carbon filters take a high volume / high cfm fan. Your 6x6x8 room has 288 sqf of air. If you didn't have the filter you could use a cage fan or online booster type fan but, with the filter you will need some type of centrifugal fan. I just order one of the valueline 6" fans for mine. Will let u know how well it works for me n a few days.

[Wickedrebel]

someone told me that if i were to run the carbon filter then the blower then light. That i would get black stuff in my light over time from the carbon filter. Is this true or do i have nothing to worry about? thanks