Darkly Labs Community

Removing the exhaust fan?

Previous to receiving my E2, I owned a Full Spectrum CO2 laser briefly. Per their exhaust requirements,  I installed a 175 CFM inline exhaust fan with an external variable speed adjuster, along with appropriate 4" dia. smooth wall metal pipe and a louvered dryer vent to outside. My plan moving forward was to shorten the pipe, and add a reducer to connect to the E2 exhaust hose, which I did and it actually worked out perfectly. The E2 hose fits into the reducer tightly. I figured I could set my big fan to a slow speed and the E2 fan would push the smoke into the pipe and the bigger fan would pull it outside. I tried it out when I did the logo test and I noticed that when I turn on the big fan the RPM’s on the E2 exhaust fan slow way down. I am worried that this arrangement might not be exhausting fumes properly, or I could be putting an excessive load on the E2 fan which will cause it to fail. So. I was wondering if I could just remove the E2 fan altogether, disconnect it from the main board and just let my big fan do all the work. In theory it seems like it would be a good idea, the big fan is capable of a lot more air movement than the tiny fan on the E2, and with the E2 fan out of the way I would get awesome unrestricted airflow.

Two things I was concerned about before I tried it…Can I damage the unit by having too much exhaust air drawing through the unit? I have the variable speed selector so I can dial it down to probably less than the stock fan so that isn’t that concerning. Also is there some kind of alarm in the software that monitors the fan functionality that would be tripped if I disconnected it? It seems like all I would have to do is unplug it from its connector on the board, and unscrew it from the back of the unit. Any thoughts on this idea? 


Below are some pictures of my setup.

Hi David,

If you are significantly increasing the airflow, I would recommend unplugging and removing the E2 exhaust fan. Your larger fan could be over spinning it and/or supplying unwanted current into the E2 board.

With the Emblaser 2 fan bypassed, your material-ignition system will not function as planned, by turning off the E2 exhaust. You will need to monitor your machine extra carefully as any material ignition will be fed quite well with the extra airflow from your external fan.

Thanks Domenic. I understand what you are saying, I think I could dial my fan speed down to only a little more CFM than the stock fan, but I didn’t realize that turning off the exhaust fan was part of the materiel ignition safety system. I guess a second option could be to take out the large fan and pipe, and place the reducer on the 2’ length of pipe that comes off the dryer louver and connect the E2 exhaust right to it… but I would need to add a few feet of hose to reach up there and I’m not sure if the E2 fan is powerful enough to handle that and push the louvers open.

So what did you ultimately do?  I’m venting to my garage right now and want to do a longer run. So I was going to put an inline fan in, and dial it down. 


Sorry for the delay in responding. I haven’t yet removed the E2 fan…I have been too caught up in using the machine and playing with Inkscape, I have just been using it the way its hooked up now with both fans running. When I have time I want to remove the E2 fan and just use the much more powerful and higher CFM inline fan I have in the ductwork. I will let you know when I make the switch and how it’s working. From just playing around with it with the E2 turned off, I am pretty sure its going to work great ! The fan I have is 175 CFM inline fan with a speed adjustment on the AC cord. So I could place the E2 farther away from the outlet, and just add more 4" round till I get within the range of the E2 tubing.