Cloudline S4 Filter Media

I’m running a Cloudline S4 with about 8 total feet of ducting and a Y split prior to the fan for the cooling tray. Putting a filter media (similar to the cooling tray filter media) in the exhaust hood is causing enough of a stall in fan suction to allow smoke to curl out of the hood, even on the highest setting. Removing the media provides sufficient air flow.

I’m curious what others are using for inline filtration?

I’ve seen the same thing with & without a filter. It’s bothersome to have the exhaust smoke just hang there not moving!

The Bullet exhaust can move a lot of air and in your case you have some of the exhaust air reduced thru collecting from the cooling tray as well. I suspect the S4 just doesn’t move enough air (about 200 cfm). I’ve thought about it a bit and in hindsight I believe I should have gotten the 6" inline fan for my use.


Thanks, Bruce…I keep thinking about setting up a dedicated fan/pipe and have wondered how strong a fan I might need. There are so many nice set-ups pictured and described on this site, hard to decide.

I was surprised how the 4" in-line extractor couldn’t quite keep up at the end of a dark roast. If the extractor is dedicated to the roaster (not shared with the cooling tray) I believe I need more than the 200 cfm the 4" Cloudline spec suggests- more like the 6" extractor which I believe has a spec of about 400 cfm. If you roast lighter you may be able to get away with the 4" Cloudline,


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I have ended up with a 6" Cloudline for the main extractor with a filter medium and a 4" Cloudline for the cooling tray also with a filter. If I am not going into dark roasts then the main extractor (6") needs only to be 1/2 power but you do need to keep an eye on the filter (as I found out the smokey way). The 4" is only on for cooling and running at full bore, but I wish now I had another 6" it would be better to have room to increase power rather than being flat out.


I have a similar type of media (blue 3m washable furnace filter material) and I am not having that same issue. S4 always at max setting.

My setup: 6 inch wide piece of filter material press fit into > 6 inch to 4 inch air duct adapter > 3 feet of black flex hose > Cloudline S4 > 20 feet of black flex hose.

Let me know if this helped

I’ll give this a go and see how it does.