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How much ventilation is too much?

Dr.Seuscio

Dr.Seuscio

New member
Hey Everyone I have a queastion. I am presently working in a 38"x48"x6.5' roughly 78 cubic feet and I am running a 8" ventilator (the kind public works and gas company use when they go into man holes) It runs @500cpm on low and I am unable to afford a dimmer at this time. I am worried about the strength of the fan because there is a lot of vacume on the door when I TRY to open it, it is so strong that i can feel a large draft coming from the door to the room where the space is. (does that make any sence?) I dont have any pics of the new fan but i do have one of the fan it replaced I can allways go back to the little booster but if it makes more sence I can put the "VENTILATOR" on intake duty and just have passive exahust thank you for your time it totaly kicks ass to know where to find answers at

Your Pal Ph.Drity
 
Dr.Seuscio

Dr.Seuscio

New member
REALLY?!?!? no one has an opinion on the subject here are some pics I will post some of the ventolator friday





I have no space to accomidate the 8" turn that the hose has to make to mount to the light so I thought i might boost exhaust to make the ac more efficent

-Seuscio
 
T

TryComb

Member
dude that is some crazy air man

Im pretty new but thats way to much air I dont know tho...

Where did you get that thing from

WOW
 
S

SwampSavant

You are burning a lot of electricity with that thing man. 500 CFM = 30,000 CFH!!! For 78 CF means you are changing the air in the room 384.6 times per hour. That is just insanity. You need to invest in a fan more on the scale of your grow area. The amount of power that thing is burning will cost you more than a new fan.
 
Dr.Seuscio

Dr.Seuscio

New member
Thanks swamp and tricomb I totaly think the same it's just that the fan i put in was 70 bucks and the comprable fan to my space is 175 so i figgured hey wtf i might as well

now i regret my desision however i think im stuck till I can afford a speed controller

do you think there is goint to be any detremental affects to my flowers im not worried about the electricity bill because I dont pay it and I have a good cover story to explain the usage (no worries)

Thanks -Seuscio

but Hey its better thain this crap Please forgive the shitty duct tape it was just to hold it till I got some foam
 
S

SwampSavant

I have never really had any experience with air flow on this scale so I do not want you to take my opinion for more than it is worth, but I do not see how it would hurt your plants. Unless they were pulled through the door seam by the vacuum effect you described earlier, lol. Your plants look healthy. I like your hood, can not go wrong with a Sun System. What size light are you running?
 
Dr Dog

Dr Dog

Sharks have a week dedicated to me
Veteran
As long as your plants are not getting knocked over by the airflow you should be fine

As for your dimmer issue, you cannot afford a light dimmer that they wold sell in a hardware store?, they are a couple bucks. I am assuming the fan is acv, basically connect the white wire to one post in the dimmer and the black wire into the other.
 
Dr.Seuscio

Dr.Seuscio

New member
Thanks a bunch Swamp and Dr.Dog

I dont see any leaves being pushed around except for a light-indirect breeze from the ocilators.

Dog- I have seen the dimmers at the Hardware store but the fan I have has a grounded plug and the only dimmer I saw that you can plug into at the Hydro Store was like 45bucks, I know they are way over-priced

I started them under a 400w MH and switched to a 1000W HPS and my temp went through the roof thats when I jumped on this "ventilator" and couldnt afford another $45.00 I just thought my high temp issues were more pressing. Is there something else i can do like stepping down the hose size or shuld i cut the plug off and re-wire into a dimmer switch

Than you both for taking your time to help me with my lacking practical knowledge

ONE LOVE-Seuscio
 
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NiteTiger

NiteTiger

Tiger, Tiger, burning bright...
Veteran
Well, you can certainly have too much airflow, and the light dimmers are a bad idea, they can reduce the life of the fan, as they are not made for the type of load a fan like we use puts on the circuit.

At my hydro store, you can get a fan speed controller, made for our applications for $25. You need to shop around bro :D I highly recommend a fan speed controller, it is excellent not only for controlling airflow rates, but for security as well.
 
NiteTiger

NiteTiger

Tiger, Tiger, burning bright...
Veteran
An 8 inch fan is overkill, but it's better to have too much fan than not enough. Plus, he's ready to go bigger when he's ready/wants to. Plus, once it's speed controlled, it's very manageable.

The biggest problem I've seen with a spot being overly ventilated is that climate controls (A/C or a heater) doesn't get a chance to work. The cold or warm air gets sucked out so quick it doesn't have a chance to actually cool or heat the space with any real efficiency.

If you read the link in my sig for TD4, you'll see that I had to go with a dedicated intake for my lights, even though I had dampers in the system for flow control.

So, no, you don't need to spend $100+ for a new 4 or 6 inch fan (never seen a 5 inch inline:confused:) Just spend the ~$25 on the speed controller.
 
Dr.Seuscio

Dr.Seuscio

New member
Will do tiger I shoped around and found one for 30 and will be picking it up today

One more question how do i determine how many CFM I am moving with a speed controll (half the dial on a 500CFM fan would be 250CFM?)
 
NiteTiger

NiteTiger

Tiger, Tiger, burning bright...
Veteran
Figuring out the actual CFM would require more in depth knowledge of aerodynamics and engineering that I just don't have. I just twiddle the knob until I've got the balance that gives me the best steady temperature range and the least noise :D
 
CannaDestroyer

CannaDestroyer

Member
drseuscio - if i was you i wouldn't change a thing. it's good to change in the entire volume of air in your space every minute, if you're not using co2. as you stated it doesn't seem to be causing any problems so just leave it. next grow if you have extra money maybe down size a bit but you still want a little overkill trust me.
 
M

MRJackHerrer

dont use a lamp dimmer on that fan or you will run the risk of fire. use a router speed controller from harborfreight.com $14.99. (ten bones cheaper then anywhere else) with the added bonus of not burning your house down.
 
B

B. Self Reliant

If your temp and humidity are fine, and the plants aren't looking ripped up from the leaves blowing around violently, then it's probably fine. A basic rule that many people go by is to be able to exchange the air within your grow space/room every 2-3 minutes. I prefer to set up my grow areas so that the air can be exchanged every minute or so if at all possible.

Probably better to be in your situation than be one of the many people who don't have enough fan power to maintain their basic plant needs such as temp & humidity.
 
B

bterzz

Active member
Veteran
While everyone else is on the subject, I just built an 8x4x10 room and am using a 6" Vortex fan to suck in air from my room and push it through my lights, out my room.

I was wondering if I could use an electronic thermostat to plug my fan into. Every time the air that in the room reaches above the desired tempature, the fan will turn itself on. Everytime it gets below the "low" tempature, the fan will turn itself off, using the lights to re-gain warmth, and then turn back on once the lights have warmed up the room.

.......right?
 
D

DeebeeAhhSee

Member
bterzz said:
While everyone else is on the subject, I just built an 8x4x10 room and am using a 6" Vortex fan to suck in air from my room and push it through my lights, out my room.

I was wondering if I could use an electronic thermostat to plug my fan into. Every time the air that in the room reaches above the desired tempature, the fan will turn itself on. Everytime it gets below the "low" tempature, the fan will turn itself off, using the lights to re-gain warmth, and then turn back on once the lights have warmed up the room.

.......right?
Click to expand...

Uhhhh.... NO!
You need a second fan. One fan should continuously move the air from your hoods.... and preferably should come from an outside source away from the room (this is ideal), closed circuit.
Remember that the lights (in my case 1k's) make an enormous amount of heat and you can't afford to have your plants be stressed out and burned because your trying to cut corners (read: don't be a cheap arse) and have the fan (1 fan) be an all purpose do it all fix.

The second fan could be hooked to a temp sensor and come on when temps get high and goes off when low.
Next thing... don't jack other peoples threads... do a search and then start your own thread (its the right and polite thing to do).

As for too much air... not an issue unless the fan is tearing up plants or something similar. If anything get some elbows for those sharp bends you have so your fan can be more efficient, take the guys advice and get a dimmer(harbor freight), and remember that when you say can't afford to get it... ask your self, can i afford not to?
I'd say the most over looked thing most grows is proper ventilation. The rule of the thumb for air exchange is five minutes. I guess it would be possible to have to complete air exchange in one minute... but at what cost? and at what sound?
Seeing that fans not only exchange air but cool the room (no a/c), its not likely in most situations (multiple light grows) that both needs can be taken care of within 60 seconds, even 2 to 3 minutes is a stretch.
 
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