can fan wiring...stop sucking my hot hair!

500cfm can fan hooked up to a smaller carbon filter, see pics.

Im running a 1000w MH/HPS in a cool tube.

Did a test run of my room last night. I kept the can fan on medium speed via the adjustable speed control while the light was on. max temp in the room was 79*. Pretty good! Well, once the light turned off(after I leave for work)...there goes all the heat. By the time I got home it was down to 68*.

I want to keep the can-fan going in order to keep negative(or positive?) pressure in the room so the smell doesnt seep out. Ill be hooking up a small fan that has a built in thermostat to provide some heat. But, I do NOT want all this heat going straight out of the can fan.

What would you all recommend I do for this? How could I wire the can fan to switch speeds when the light is off(from med to low)? Perhaps I need to time it to turn on and off while I am home so I can adjust the fan speed? Id like it to be automated in case I cant adjust it....

older pic,

room is now finished, just trying to get everything wired and running right before I bring the green in. I dont want to find out I have temp issues after the plants are under way.

so whats wrong?

a lil drop in temp at night isnt gonna effect much, in fact it will help cool resivoir/root temps. once the lights come back on the temp will soon be right back to noraml range. now if it were more considerable i would take action.

i grow in my garage and last winter I had to heat the tent and have had similar issues. I did get it figured though. I bought a switch that controls the speed of the fan during light and during dark with two separate controls. I have it set so that the hotter it gets the more air it exhausts but when the room is cool it slows down or even stops. Between this sytem and my heater on a thermostat i can keep the tent in optimum temps. (70-80)

BCcannabis said:

i grow in my garage and last winter I had to heat the tent and have had similar issues. I did get it figured though. I bought a switch that controls the speed of the fan during light and during dark with two separate controls. I have it set so that the hotter it gets the more air it exhausts but when the room is cool it slows down or even stops. Between this sytem and my heater on a thermostat i can keep the tent in optimum temps. (70-80)

Click to expand...

Where did you get this switch??? Sounds like what I need!

Ak - you dont think the drop in temp is a bad thing? I mean, right now its droping to 68*, come winter time, its going to drop even more. I dont want it to get to cold in there...

why dont you get a simple timer and set it for the same time as your lights or maybe an hour longer after your lights turn off.

jdmcwestevo said:

why dont you get a simple timer and set it for the same time as your lights or maybe an hour longer after your lights turn off.

Click to expand...

I dont want air seeping out of the room when the fan isnt running. then again, I have sealed the room pretty good. This is my first grow, I might be over thinking this....my current understanding is you want to maintain a negative pressure inside the room to prevent the smell from escaping the room. I would like to run c02 eventually as well, in which i understand ill have to kill the fan completely for about 15-20min while I release c02 in the room.

a drop in temps at night is natural. if your over 60f i wouldnt worry.

OlBlue said:

I dont want air seeping out of the room when the fan isnt running. then again, I have sealed the room pretty good. This is my first grow, I might be over thinking this....my current understanding is you want to maintain a negative pressure inside the room to prevent the smell from escaping the room. I would like to run c02 eventually as well, in which i understand ill have to kill the fan completely for about 15-20min while I release c02 in the room.

Click to expand...

even with negative pressure smell WILL seep out. especially the negligible amount of pressure that little fan will create. trying to run CO2 in that room will not work well. that fan will pull out ur co2 as soon as it kicks on for a few minutes. you need to pick sealed room or negative pressure with passive intake

jdmcwestevo said:

even with negative pressure smell WILL seep out. especially the negligible amount of pressure that little fan will create. trying to run CO2 in that room will not work well. that fan will pull out ur co2 as soon as it kicks on for a few minutes. you need to pick sealed room or negative pressure with passive intake

Click to expand...

I have placed panda film on nearly every surface and have taped every seam, so, it does differ from the pic you are looking at right now. not sure if this will play much difference, however, I think it would. There are only a few spots that are "open" for air to leak. The staple holes, the bottom of the panda film(which will be taped soon), around the door(which Im working on sealing better than it currently is, big gap at the bottom), and the random small gaps around the duct work. Also, how is a 500cfm fan "little"? This room is only 8'x9'x8' at MOST(forget the actual dimensions).

500 cfm will do that area in most cases, unles your intake temp is sky high

ak.fortyseven said:

500 cfm will do that area in most cases, unles your intake temp is sky high

Click to expand...

quite the opposite. intake will be getting lower and lower as we progress into winter. typical winter temps around my area will be around 20-30 over night and the 40's during the day.

OlBlue said:

quite the opposite. intake will be getting lower and lower as we progress into winter. typical winter temps around my area will be around 20-30 over night and the 40's during the day.

Click to expand...

get a fan controller and lower it progresively as the temps fall, lower night temps arent so bad, growing temps are of concern.

OlBlue said:

Where did you get this switch??? Sounds like what I need!

Ak - you dont think the drop in temp is a bad thing? I mean, right now its droping to 68*, come winter time, its going to drop even more. I dont want it to get to cold in there...

Click to expand...

I got the switch at a local grow store, if i remember right it was $100. When my girls wake up tonight i will get a name off the switch for you. It really does do a good job and still maintain negative pressure.

ak.fortyseven said:

get a fan controller and lower it progresively as the temps fall, lower night temps arent so bad, growing temps are of concern.

Click to expand...

I have a fan controller, but I have to adjust it myself. I want it to auto adjust depending on temp. wishful thinking, but sounds like BC has something like this.

http://www.growwurks.com/c-a-p-controllers-vsc-dne-variable-fan-speed-contoller-day-night.aspx

unfortunately i think this company has these on back order from the maker. I have the model that doesnt adjust fan speed myself. I have a small 4" fan with a carbon filter that runs 24/7 to give me a constant negative pressure. My 8" exhaust is connected to the thermostat. This suits me very well.

I use a SMSCOM twin speed controller and it absolutely rocks. It controls the intake and outake or in my case the air cooling on the lights and the outtake.

When I was looking at Co2 I was looking at getting a co2 sensor and some kind of usb Co2 controller so I could follow the historical Co2 levels and work out what was best for my plants.

What exactly are you after ?

The evolution twin fan controller also controls heaters and co2 if I remember rightly saw one at my local store, Looks swanky I want one to add to my lets make Mouse do less work and have a better grow collection !

Mouse

I'm a bit of a newb, though a fast learner, and I have to agree with the statement that 68 degrees at night is perfectly acceptable. From what I've read in books regarding indoor growing, it's actually the variance between the evening and day temps that can begin having an adverse impact. I don't think you should be worrying unless your variance is greater than 20 degrees (please find literature to back this up - I am not an expert, just well read).

After you place you girls in I want pictures.

68 is more than fine for lights off. I only worry around 55. Small heater to be safe

Duku said:

After you place you girls in I want pictures.

68 is more than fine for lights off. I only worry around 55. Small heater to be safe

Click to expand...

I picked up a small heater for the room to be safe. I have a thread going in the DWC section already. Ill post a link in my signature.