M
m00nchild
What happens if the CFM rating of a carbon filter is less than the CFM rating of the blower?
M
m00nchild
Thanks for the replies. So, I'm using a 265 cfm blower, pulling through a can filter rated at 94 cfm (can filter 2600), in a 80cf closet... it's been getting very hot in there and I've been wondering if the filter was creating a bottleneck... seems that's not the case then. That can only mean my 265 cfm blower is just not enough for the 80 cubic feet. Either that, or the dayton-style blowers don't handle backpressure very well. I guess it means I'm getting another fan...
That sucks, because I really felt that 265 cfm would be plenty of power, but maybe I need an inline fan instead...
That sucks, because I really felt that 265 cfm would be plenty of power, but maybe I need an inline fan instead...
well thats a bigger difference, it needs be a little closer. later in flower, that scrubber wont be able to kill all the smell. 80 ft^3 closet? you will definately need a bigger fan. for reference, ill be using a 270cfm fan for a 5'Hx4'Wx2'D cab, about half your size. i think vortex has a 440 cfm inline fan that would work much better for you.
petemoss
Active member
m00nchild said:
A Can 2600 has a 42 cfm rating according to the Can web site. Much too small for your Dayton 265. I used the same blower with a Can 33 (200 cfm) to exhust a 576 cu. ft. "grow tent". Airflow went filter, 1000 hps in hood, Dayton 265, out the window. Worked beautifully, cool lights, zero odor. It's funny you mentioned the Can 2600 because I just got one for a small cab. Want to downsize that same airflow setup for a cab.
rather than start my own thread, I'll see if anyone notices this.
Conversely to the original question, what happens if the CFM rating of the fan is significatnly lower than the CFM rating of the carbon filter?
Would there be any ill effects, like the carbon getting becoming ineffective sooner?
Batboy
Member
I guess it would depend on whether you are talking about the min or max cfm rating of the filter. If you are using a fan that is lower than the min rating of the filter, then I think that the fan wouldn't be strong enough to move air effectively. You probably wouldn't pull enough air in to the carbon to kill the odor and if you are also trying to use the fan for cooling, it won't be strong enough to do that either.
Min, as in fan is strong enough to exchange the air the proper number of times but filter is overkill for the cfm going through it. The higher rated filter I think would present less static pressure than one rated closer to whatever the fan can move, which is why I was wondering.
Except the problem with stuff sold in packages is that one piece (or more) is never exactly what you want. Since I'm exceptionally anal/ocd, that never works. I want to feel like I picked the perfect part for every last little detail.
Now, if someone was pairing Can Filters with S&P Mix-Vents and offering the package cheaper than buying each separately from the cheapest source, great - bu no one does.
But it was more of a curiosity thing since even though I'm expecting to have different fan speeds dialed in for day and night, they both fall within the min-max range of filter I'm planning on, assuming my guesses on static pressure are not absurdly wrong.
Batboy
Member
My turn to ask a question -- how are you doing this? I've got an S&P fan with a speed controller and I would love for it to automatically slow down/quiet down when the lights are off.
The light timer will also drive a relay that switches between two separate circuits with a different speed controller hooked to each dialed into different speeds. The relay ensures only one circuit is powered at a time, so the fan will either be running through the day-time speed controller or the night-time speed controller.
It will be 2-3 months before I'm actually wiring this up, so just the general idea for now, but I plan to document the cab build here.
I also thought about doing the switch between the S&P's low-speed and high-speed circuit, but that gives less control since you only have one knob to set and difference in speeds between the two would be fixed. For the $20 extra, I'll just add another controller instead.
It will be 2-3 months before I'm actually wiring this up, so just the general idea for now, but I plan to document the cab build here.
I also thought about doing the switch between the S&P's low-speed and high-speed circuit, but that gives less control since you only have one knob to set and difference in speeds between the two would be fixed. For the $20 extra, I'll just add another controller instead.
You can also get a plug and play thermostat pretty cheap, I think about $80aud at a hydro store, and that will accomplish a similar result.
Batboy
Member
qbert - you are clearly more knowledgable than me in the electrical wiring department and I'm lost once you start talking about relays and switches and multiple speed controllers. I will look for your thread when you start the build. Good luck
Scrubninja - I thought that thermostats just turned a unit on and off depending on temperature. Are you saying that there are units that adjust fan speed depending on temperature or time? Can you please elaborate?
Scrubninja - I thought that thermostats just turned a unit on and off depending on temperature. Are you saying that there are units that adjust fan speed depending on temperature or time? Can you please elaborate?
You can get anything that will do anything these days
I was talking more directly in terms of what you mentioned - you can get thermostats which have a minimum speed setting so when the lights go off, they won't stop altogether. Otherwise you'd lose negative pressure at lights out and smell would leak out. I'm pretty sure you can get them so they speed up and slow down like you asked. Google hydroponic thermostats and there's some crazy (but expensive) shit.My computer fan has a thermostat included and it stays on a minimal speed no matter how cool it is, and speeds up and slows down depending on temp.
I should mention the price I mentioned I was actually thinking of the simple on/off version so it will cost more than that.
Edit: This is what you mean, right?
http://www.grozonecontrol.com/TV2_en.html
Last edited:
Batboy
Member
Great find ScrubNinja, and not crazy expensive either! That's basically what I was talking about, but I think that I would prefer a speed controller that sets the fan speed to X% at a certain time and Y% at a different time.
Basically, because my fan serves to both cool my light/cab AND filter/exhaust air, there will come a time when the fan will need to stay on after the light goes out. I want a controller that can be "told" to run the fan at a low speed of my choosing during darkness that still is sufficient to maintain negative pressure and control smell, then turn the speed up (but not necessarily to 100%) during the day when it is necessary to cool the light and handle odor/exhaust. Does that make sense? qbert - is that what you were getting at?
Basically, because my fan serves to both cool my light/cab AND filter/exhaust air, there will come a time when the fan will need to stay on after the light goes out. I want a controller that can be "told" to run the fan at a low speed of my choosing during darkness that still is sufficient to maintain negative pressure and control smell, then turn the speed up (but not necessarily to 100%) during the day when it is necessary to cool the light and handle odor/exhaust. Does that make sense? qbert - is that what you were getting at?
Yeah, exactly. I wasn't really sold on the idea of fan speed changing in relation to temp because. idk, just seems a little too out of my control. I would really hate for some unexpected reason to have the fan kick into high gear at just the wrong time. Granted its a far-fetched scenario, but sh*t happens, ya know.
Now, rattling around in the back of my head I have all kinds of really neat ideas about advanced custom computer control, but if I go there this project will stall out from overthinking.
I'm seeing those controllers for $110 on ebay. Anywhere else to buy them?
Now, rattling around in the back of my head I have all kinds of really neat ideas about advanced custom computer control, but if I go there this project will stall out from overthinking.
I'm seeing those controllers for $110 on ebay. Anywhere else to buy them?
Batboy
Member
That New England Hydro seller on ebay (or their standalone site) are the only places I've seen it.
I totally agree about not wanting/needing the thing to vary speed based on temperatures. I'd rather set the speeds. Having said that, you can program the idle, low temp speed, so we are halfway there. I know that with my current setup, I never need to go to 100% power. I have 2 thoughts about controlling the top speed:
1 - My fan is currently hardwired with an external speed controller. Would it be crazy, wrong, dangerous to keep that controller wired, turn it to my desired top speed, and plug the whole thing into this new controller. I wonder if this controller would still be able to raise and lower the speed, but when it thinks that it's going to 100%, it's really just going to the max speed that was dialed in on the other controller. I am guessing that won't work but I'd love an opinion.
2 - By setting the daytime target temp relatively low, the controller shouldn't very often need to turn the fan to 100% to reach the temp. The drawback here is that it seems as though the fan would be in a constant state of flux between low temp speed and high speed, whereas I prefer a constant.
I totally agree about not wanting/needing the thing to vary speed based on temperatures. I'd rather set the speeds. Having said that, you can program the idle, low temp speed, so we are halfway there. I know that with my current setup, I never need to go to 100% power. I have 2 thoughts about controlling the top speed:
1 - My fan is currently hardwired with an external speed controller. Would it be crazy, wrong, dangerous to keep that controller wired, turn it to my desired top speed, and plug the whole thing into this new controller. I wonder if this controller would still be able to raise and lower the speed, but when it thinks that it's going to 100%, it's really just going to the max speed that was dialed in on the other controller. I am guessing that won't work but I'd love an opinion.
2 - By setting the daytime target temp relatively low, the controller shouldn't very often need to turn the fan to 100% to reach the temp. The drawback here is that it seems as though the fan would be in a constant state of flux between low temp speed and high speed, whereas I prefer a constant.
