Have you cleaned your exhaust fan on your Roaster?  The North TJ-066 Mill City 500 gram coffee roaster requires basic maintenance including cleaning fan assembly.  I previously posted a video how to clean out the exhaust fan on your roaster.  You can see the original video where I walk you through the steps to remove, clean and put back on the fan unit for the roaster.  This fan controls the airflow for the roaster.  Recently, I noticed my airflow would drop off and then kick back up without changing the dial on my airflow knob.  After reaching out to Mill City Coffee Rosters, Nick suggested I start by cleaning my exhaust fan.    Not only vacuum it out, but take apart the fan assembly because fine coffee chaff particles get jammed behind the fan blades (Impeller) and can influence the air speed.

This video details the impeller fan blade removal, cleaning and reassembly. Hopefully this step will not only be part of my regular cleanings, but will address the mysterious fan speed changes I have been experiencing. Share your comments here or on youtube.