Wow, my 2006 you have to check the light to see if it’s running. The GF I can hear in other rooms.
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Thanks for running and documenting that test! The latter test with the softer hose sounds a lot better than the one with rigid pipe but I’m also wondering why the flow rate seemed to drop so much in the second test. Is it possible that the soft hose was leaking inside somewhere, presumably at the hose connections?
The walls of those tubes aren’t smooth. They cause a lot of turbulence, especially around turns
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Fantastic experiment. I’m debating cutting a dedicated vent in my wall or using a window vent, and had been wondering how to pick tubing. This will help!
Wonder if this would work?
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Going to guess not. Says it’s not for kitchen exhaust systems. Heating and A/C systems, the intended use, don’t put out any particulate or flammable gasses. Looking at the smoke from the GF reminds me of the nasty stuff that gets vented from my cooking.
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Good point! I was thinking it would be OK with the heat, wasn’t thinking about the smoke.
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I don’t know, offhand, what year my dishwasher is as it came with the apartment. It can be heard in another room, though. I’m more concerned about the comparative volume of the pro with filter as I try not to be too noisy for my neighbors. I have my coffee grinder in a box with some padding because I am convinced that the burr mill can be heard in the next building over without it.
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Good point. It would be interesting to see a flow rate vs delta P curve for the GF fan, but GF doesn’t seem to release technical data of that sort.
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After I did this experiment I realized I totally should have put a flow meter in the test too, but given the amount of blood loss in quickly changing over the duct in the walls, not excited to try again…
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Good lord - you actually have the hardware to measure exhaust velocity? You’d be a fun neighbor with your vast collection of gadgets!
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No, but I have a father and a son who are pilots (both powered and glider) so they have a pocket wind gauge.
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Ah, there’s dedication to the advancement of human knowledge.
I did a bunch of tests back in Dec.
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I remembered that. Maybe if I get inspired this weekend, I will switch back and do a CFM comparison…
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It only matters if you’re not going to follow their guidance of a flexi-hose with no more than 2 90 degree bends and 10 ft in length. If you do that, the extra turbulence isn’t an issue. For @karaelena, he needed to do a really long run with elbows (and booster fan) in which case it makes sense to worry about flow restrictions and turbulence.
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I note that now when I shut the lid the flexible hose puffs up for a second, which indicates to me there is some flow restriction (it’s only 8’ from GF to outside)
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One thing to consider (and something I dealt with when I modded my K40 by adding front intake fans) is that the output cannot exceed the capacity of the unit to breathe. So the tighter the box the less air going in, the less that can go out…until the exhaust fan is powerful enough to crush the intake manifold (the laser enclosure in this case) 
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The “restriction” in this case is the air already present in the vent hose before you close the lid. The air has its own mass, inertia, and it’s affected by gravity. Since your GF is lower than the vent outlet, there is a weighted column of air inside the vent hose and it puffs up because when you close the lid, you’re essentially pumping air from inside the house directly into the vent.
Or, the static air pressure inside your basement could be slightly lower than the outside air because of HVAC system, or an open chimney flu, or simply heat convection (ie: warmer air upstairs rising thus causing a slight draft/vacuum in the basement). This could cause air to flow from the outside, down the vent hose, so when you close the GF lid, that airflow is immediately stopped and you get an air/water hammer effect in the hose.
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Sorry if I have missed this, but do the exhaust fans stop when the print is paused?