Buzzing from inline fan after installing speed controller

Guest · Sep 5, 2007

I am using the Fantech FR110, its a 4", 167cfm fan that is supposedly quiet. I have had this fan before and used a router speed controller from a local shop (they said it would work for fans and you just plugged the fan into it) and this time I ordered one that must be wired into the setup from the same place that sold me the fan(contractors website). They both make the fan 'buzz' when you turn it on. Its kind of like the sound a pair of hair clippers make when they start up. It is loudest right when the fan starts up and then the sound of rushing air dampens the buzzing some but not much when I run this at about half power. I am making some custom ducting/silencers to help with the rushing air sound but I need to figure out why this buzz is so loud and I dont want to run the fan on full power to cover up the noise.

I got this one:

http://www.rewci.com/rospcowionsw.html

Should I have got the 10 amp one or another on this page?

http://www.rewci.com/cosw.html

Anyone have a Fantech with another brand/style of speed controller that doesnt make the buzzing noise Im talking about?

HappyHemphog · Sep 5, 2007

I have the same fan and got it from the same company (they have great prices, no "hydro" markup) but I don't have a controller on it.

Are you sure the buzzing is electrical in nature and not caused by anything rubbing?

I have a another Fantech (FX6XL) I have mounted on the ceiling.. I was changing the wiring one day and after I was done and fired it up it made a horrible buzzing-like sound. Turns out I had nudged the fan just enough to cause the fan blade to tag the screw holding mounting bracket. I added a washer under the screw and kinda bent the mount so fan wouldn't hit the screw. This fan does have the speed controller, but haven't had any electrical buzzing problems, so I would think using a heavier rated controller won't help ya.

Guest · Sep 6, 2007

hey Hemphog, it is not from anything rubbing, I just wired it up on the floor. The buzz starts immediately when I turn it on before the fan gets up to speed and you can only really hear it when it is less than about 75% power. Maybe I'll give Fantech a call and see what they say.

Harry Gypsna · Sep 6, 2007

all; speed controllers(apart from the really expensive ones that control voltage as opposed to ****ing with the resistance/waveform) will buzz.... you hear it at lower speeds....mine buzzes a bit less if i turn the fan on at full speed and then lower it...ie dont turn it on at a low speed...also... i just got sopme more speed controls to use and the supplier said really it isnt a god idea top tuirn these type of controllers down lower than half way for some reason..... obviously some fans will stop turning at different settings.

george j warner · Sep 6, 2007

yer all grow fans buzz at low voltage ..relax its normal,theres normally a point where it stops buzzing and the airflow is all you hear at about 40% ,so always have it higher than that point : )

Mister Postman · Sep 7, 2007

I just wired one up last week, and have very lil if any noise other then motor.. Damn near silent when turned down low.. It is a lil louder at lower speeds say barely moving- to low, but once you get the motor actually moving is nothing more then the motor, and of course air rushing through ducts at high speeds.

Picked it up at lowes. it's a Lutron 5a made for exhaust fans (pole style, and those requiring solid state speed control is stated in the directions, and thats what we want). They sell a 1.5a, and 5a.. the 5a is what u want for these heavy duty inline exhaust fans, the 1.5a is for ceiling fans.. They are located In the section with all the other dimmers for lights, and fans. Cost me $17 for the controller, extension cord, and gang box. controller itself was $9 and some change

Maybe it's my fan as i am running a 6in Ecofan on it, but for 9 bucks it may be worth a shot, as I don't much if any hum, and nothing I would consider a buzz LOL. Save the receipt, and if it's no better return it, if it's better be sure to post back and mention it, as I'm sure a buzz can can pretty annoying over time, and not the greatest for stealth.

Guest · Sep 7, 2007

Thanks for the responses guys. I thought I read somewhere that its better to have a bigger fan running at half power than a smaller fan running at full power. So I went with a bigger fan but I want everything super stealthy. Im not worried about it burning out the fan, just the noise but I was told to disconnect the controller if I get a buzzing because somethings not working correctly. I'll see if I can find a Lowes around here with that controller and see if it works any better.

maybe I just need to make bigger silencers and toss the speed controller but Im running out of room if I want this to be hidden.

george j warner · Sep 7, 2007

yer i probally said that lol .. its true : ) and if you want even less noise do this :

no sound at 100% ....only sound is air being sucked into intake vent : ) `and a carbon filter muffles that :rasta:

waydee · Sep 7, 2007

I've wondered this, I dont think normal dimmers are good for inline fans, the Systemair data sheet for my 125mm says its speed controllable via an electronic controller. A normal fan dimmer causes it to buzz and it doesnt sound like its doing it any good. An electronic controller seems to be more expensive too but i'm going to pick one up and see if it stops the buzzing.

edit: cadamp.co.uk sell a 1.5a electronic controller for £22 probably ex vat.

Guest · Sep 8, 2007

I packed 3 blankets around the fan and ducting yesterday and ran the fan at 100%, it managed to muffle most of the noise coming from the fan. Im thinking I might try to make a box like you have george but I might just build 3 sides of a box, mount it against the wall/floor and stuff it with blankets or stuffing like you have. The blankets packed around the fan actually did a lot more than I expected and I think a wall of mdf would make it near silent. I also bought stuff to try and make a bigger silencer to see how quiet I can make the rushing air with the fan at 100%.

Harry Gypsna · Sep 8, 2007

theres a guy at uk420 who just wrapped his RVK150 in fibreglas insulation and cling film...... did the trick appatrently although to me it seems like a fire risk(does fibreglass burn)

Kenny Lingus · Sep 15, 2007

^ nOPE! FG insulation is fire proofed usually

Guest · Sep 16, 2007

I dont think normal dimmers are good for inline fans

I'll confirm that normal dimmers should not be used with inline fans. You need a solid state controller. In the long run you'll ruin your fan with a conventional dimmer.

I thought I read somewhere that its better to have a bigger fan running at half power than a smaller fan running at full power. So I went with a bigger fan but I want everything super stealthy. Im not worried about it burning out the fan, just the noise but I was told to disconnect the controller if I get a buzzing because somethings not working correctly. I'll see if I can find a Lowes around here with that controller and see if it works any better.

Some inline fans are just plain and simply noisier than others. Part of it is just the volume of air running through a particular size ducting or a 300 cfm Elicent will generate less noise than 447 cfm Vortex. Those Vortex's sound like a jet engine taking off when they fire up. Using oversize ducting does help some. Insulating ducting does help some. Most of the noise is on the intake side. There's so many threads on this subject I've lost track.

Guest · Sep 22, 2007

Hey george J how did you seal the ducting hole in your mdf box? was it airtight or just had tons of wodding packed around it? Do you think the acoustic material was really necessary? I am not really familiar with MDF and its sound deadening properties.

Guest · Oct 16, 2007

So I built a 3/4" thick mdf box for my 4" inline, I have 7" hard ducting with 1.5" foam lining the inside but I still have too much air noise with the fan running at full blast. I really wanted to run the fan at 100% but its just too noisy and stealth is my #1 priority. Even if it is expensive for an electronic speed controller, if it works, I will buy it. Does anyone know for sure if those will run a fan like mine, Fantech FR110, without the buzzing? Anyone got a link or know what kind of store I could find one locally? The whole project depends on this! :bashhead:

marx2k · Oct 16, 2007

Mountain said:
I'll confirm that normal dimmers should not be used with inline fans. You need a solid state controller. In the long run you'll ruin your fan with a conventional dimmer.

Some inline fans are just plain and simply noisier than others. Part of it is just the volume of air running through a particular size ducting or a 300 cfm Elicent will generate less noise than 447 cfm Vortex. Those Vortex's sound like a jet engine taking off when they fire up. Using oversize ducting does help some. Insulating ducting does help some. Most of the noise is on the intake side. There's so many threads on this subject I've lost track.

I'll second this.. my 6" Vortex does sound like a jet engine. But DAMN does it SUCK! It's loud even with a solid state controller turned all the way down, and it's less loud with ducting attached to it. I'm pretty sure the noise will be manageable when I output it to a carbon scrubber though

Guest · Oct 16, 2007

I take it you are not sleeping next to the fan marx2k? I could probably deal with some noise, but I dont want my friends hearing it and asking whats that buzzing noise coming from your closet??

Does anyone know if a rotary style controller, like the one I have, is different than a solid state or pole style controller? I guess I'll go to HD or find a Lowes and see if the pole style one works any better.

Guest · Oct 16, 2007

Why are you trying to cut down on such a low cfm fan? Buy an inline damper and regulate the air flow, no noise and nothing to burn up Check Lowe's, in the sheet metal and ducting supplies section.

Guest · Oct 17, 2007

Ty-Stik said:
Why are you trying to cut down on such a low cfm fan? Buy an inline damper and regulate the air flow, no noise and nothing to burn up Check Lowe's, in the sheet metal and ducting supplies section.

Ha!! I was wondering the same thing!

Personally, I like my Dayton squirel cage blowers better than Vortex. They are cheaper and quieter. My Dayton 465 sits on a chair beside grow tent with no insulation, no muffler at all on the output. I can't hear it in my other bedroom. I also have neighbors in the room directly above my grow. No complaints from them(actually second set of neighbors since I began growing)

Xtrakritical · Oct 17, 2007

You don't want to set the speed too low because the motor is designed to be cooled by the air moving past it. Slowing it down reduces the cooling and can burn the fan up

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Buzzing from inline fan after installing speed controller

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