Can I Super Charge a Cheap Duct Fan With A Ceiling Fan Speed Controller?

Honey Oil Riot Squad

Well-Known Member
Hello all,
My grow tent has been a bit too cold lately. I'm drawing in cold air with a duct fan from a vent outdoors to cool the tent. This method has worked great for me to keep the tent cool for the majority of the year, but I have a slight problem. When I have this duct fan on, it's too cold. When I have this duct fan off, it's too hot.

It is just a cheap suncourt 160 CFM duct fan from home depot (a nice combo of like 3 of these in different sizes works really well to keep my small tent cool without having to get expensive overpowered fans). So of course the simple solution here was to just get a speed controller attached to the thing so that I can find a happy medium that supplies the right temperature. So I took a trip to the hardware store and all I could find were ceiling fan speed controllers (that you would normally install in your wall). I figured it wouldn't work, but it was 10 bucks so I decided to try it anyways, what the hell.

I hooked it up and tried it out and a very strange thing happened...
There are 3 different settings on this low, medium, and high. ...bongsmilie <--"high".
So the low and high settings don't seem to change a thing with the fan, it seems to blow at the same speed. But the medium setting, oddly enough, actually boosted the fan speed, and I mean by quite a bit. Now I don't have an air velocity meter (who does?), but I'm pretty sure that the CFM of this cheap $30, 6" home depot duct fan damned near doubled.

And now I'm sitting here thinking I just stumbled upon this ingenious invention where I hacked this cheap 30 buck duct fan into something with the power of a much more expensive duct fan for $10.

Although my only thought is that maybe I am screwing with a resistor or wiring or whatever in the fan (I am NOT an electrician lol) and that this will only really work for some time before the fan breaks on me and burns out or something. So does anybody here have electrical know-how or stumbled upon this same thing with their duct fans before as well? Does it work to keep them running while "super-charged" like this? Or am I just gonna break my fan after a while?

This is kind of a strange question... so thanks for ANY help. I might just put this on my outtake vent and do a passive intake instead, if it does work...
 

chernobe

Well-Known Member
Throw that switch in the garbage and get one that is made for inline fans for gardening The one you have is not going to do the job safely. It is supplying more power than you need to that fan and it can cause a fire hazard from being overloaded. Just go online they are pretty cheap $10-$15. Hope this helps, good luck
 

Honey Oil Riot Squad

Well-Known Member
LOL... I think I had found my answer after some deeper research just after posting. No worries, I am not running it. No fires. I know a variac will work but I mean the price is truly insane on those. Not worth it. I took the whole fan off and left it a passive intake. Seems to be working until a warmer day comes by and it gets just a bit too hot. But not too bad. I will look into these temp controllers, does that just shut the fan off and on with temp readings? Didn't know those could get that cheap. Thanks!
 

Honey Oil Riot Squad

Well-Known Member
Sounds like it'll overheat the coils in the fan motor because this is designed for a 1.5 amp ceiling fan, not a 0.4 amp duct fan. You end up with extra current flowing through the fan motor which heats it more than it's designed for.
 
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