Coffee-Tech FZ94: cleaning roast chamber & heat elements -- burners
Michael Wong sent me the following report about his project to clean the heating elements of the FZ94, ensuring maximum heat efficiency. (I myself use a powerful blower to blast ash and dust out of the roasting chamber. First I make sure all doors and windows in the house are open so clean air blows in, and afterwards I vacuum clean the floors).
Yotam Mendelsohn from Coffee-Tech adds this message:
The gaskets are available all the time as separate item.
However, when you order heating elements, we also ship with each element a gasket.
Here is Michael's report:
I would like to share with you my day long maintenance on the FZ-94. (burners and ash cleaning)
A while back we noticed the right side burner was not heating up to its capacity (not glowing red hot).
So I emailed Coffeetech, and Yotam kindly replied with instructions for disassembling the burners from the back of the machine.
While pulling out the burners one by one, they were accompanied by huge amount of ash deposits. Very important to arm yourself with a vacuum cleaner while doing this.
Then I realized the original (cotton/fiber) type of heat insulation gaskets had all disintegrated due to long term high heat. I had an out of body experience as I wasn’t prepared for this to happen.
Luckily I googled and found a local custom gasket company, they found me the paper fiber type that can withstand high heat up to 800+ Fahrenheit.
I bought a sample sheet from them, with $5 CDN donation to their office coffee fund.
The rest was easy, just measure and custom cut to size and shape.
I used a sand paper to clean up all three burners (1000w heating elements), so the deposits were sanded off nicely. I believe long term neglect will result in uneven heat distribution along the element which might crack the unit itself. (Please correct me if I’m wrong here)
One tool I had never expected to be handy here, the office-one-hole-puncher. That made life easy as I had to fine-trim the hole size for the burners that the gasket needed to wrap around.
Please share this to the awesome FZ-94 community !
Today I learned a lot!
Regards,
Michael.
cc Yotam (thank you Yotam!! Helpful as usual!)
Reacties
Do you know if Michael ever experienced this issue again or ever found out the true cause of the heating element failure? I am also using a Coffee-Tech FZ94 Evo and the heating element in the same position as Michael's has failed twice in less than a year. Coffee-tech replaced the first (still waiting to hear back about the 2nd) but did not provide any information as to why the element failed or what I could do to prevent further failure.
Raf
I do not know if Michael had this issue since.
On my FZ94 I have never had an element fail.
My personal best guess is that this may be because
1) I keep airflow above a certain minimum to prevent overheating
2) I keep the drum rolling above a certain speed to keep air whirling around the elements
3) whenever there's a strong wind outside, i open big windows in the front room and I open doors in the back of the apartment so a strong wind pulls through the home, and I use a very strong blower to blow out any dust / ashes in the roasting chamber that's been building up on the bottom. This way the elements are not covered in ashes that would prevent them from getting rid of the heat energy.
4) I have the elements on 100% power when warming up but once the roasting has begun I gradually lower the power that's going into the elements, using the extra FUJI PID. So there's much less heat going through the elements by the time the machine gets really hot at the end of a roast.
5) I almost never do back-to-back roasts. So after one roast the entire machine is cooling down.