My overhead exhaust hood starting making a serious noise at high speeds after 390 medium to light roasts, I decided to take apart the encased blower unit and discovered a complete caking of coffee dust clogging the air flow of the blower blades. After a complete cleaning it is back to working properly. The exhaust uses baffle type filters which evidently don’t collect all the particles flowing out of the Bullet during roasting. I will have to add this cleaning task to my maintenance schedule.
