I read with interest that someone's Hottop burned up due apparently to chaff buildup in the circuit board/motor compartment, so I pulled the fan off mine and looked. I had a huge collection of chaff among the components on top of the circuit board and drifted into the corners, anywhere it could drop out of the airflow. I had replaced the heating element two years ago, and the machine was cleaned thoroughly then.
To obtain a larger sample I called Zara Haimo, who owns Alfred's old machine and arranged to go by today and look at it with her. I didn't know Alfred but had heard the story on the list, the point being that the machine is one of the "elders" of the breed. Surprisingly, though it had never been disassembled and cleaned, her machine had significantly less chaff than mine. I don't believe the condition of her machine constituted a significant fire hazard, (mine definitely did) but It did have enough chaff and dust that I feel much more comfortable knowing it has been removed.
The debris in my machine contained a large number of relatively intact papery skins from the beans. I was puzzled as to how so many large bits of debris were getting from the chamber to the motor compartment, til I spotted the opening in the dump chute for the linkage from the solenoid to the bean dump door. My working hypothesis is that with the main fan running, when the door is open during the bean dump there is enough airflow up the chute from either the roast chamber, the cooling tray or both, that it may carriy some chaff through the linkage opening.
I do happen to be very fond of dry processed coffees, and purchase and roast a relatively large percentage of heavy chaff producing beans. I can't speak to Zara's preferences, but will be interested to find out.
Do I love my Hottop any less? Not a bit. Would I give it up? No way! Will I check it more often? Yes indeed.
Bottom line, never leave the room while any roaster is in operation.
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