Hi,
My Quest M3 heating elements crapped out again. I originally posted about that issue here here and then discussed the process of swapping in the new elements here.

So after about a year and a half I am having the same symptoms; the power only goes about halfway up the dial when I crank power to full. The new elements appeared to run a good deal hotter than the older ones, I get some charring in the inside of the machine. The M3 is pretty simple, so it should be able to basically last forever; but I bought mine in 2016, so it isn't like off the charts that I might want to replace it.

Also, the larger batch size of the M6 might be pretty cool...I think I will do a thorough cleaning and make sure all the connections are a-ok, and see if I can get it fired up again, but how long should an M3 be expected to last?

thanks!!

IMO, it should last forever, with only minor maintenance. The elements in my M3-Mk2 never died while I owned it, and it's likely still going strong somewhere. Likewise, thus far at least, the elements in my M6 have never failed. I can think of only two things that will repeatedly kill the elements: overvoltage and lack of air circulation. Are you by any chanced using an autotransformer, such as a Variac, to boost the voltage? If not, have you measured the line voltage at the socket into which the M3 is plugged? The instruction sheet for the Quests mentions not using a Variac, likely because overvoltage would kill the elements.

Concerning air flow, I notice from your other posts that your M3 variant has air tubes, making it a fairly rare model. You might check to see if one or more of them has become blocked with something, albeit this is unlikely. Most early M3 roasters had a single, fairly large air hole at the back of the roaster; most recent ones, and the M6, have air slots in the outer cover, one on each side of the ash drawer, which is also a more recent addition. I have no experience with your model, but I wonder if those air tubes provide enough area for proper air circulation. Perhaps others with that model will chime in and tell us if they've had repeated heater failures.

As for operator issues, I can't think of how one might kill a Quest, save one. Have you, by any chance, overheated your Quest while warming it up? It would be easy to become distracted and superheat the thing, as the Quests have no safety thermostat. That is, if you leave them with max heater current and min fan, they'll keep getting hotter and hotter, which could do in a heater. For reference, I preheat to 250C ET/BT (empty), and have installed a PID to limit the MET to whatever I set (currently at 350C), just in case I get distracted in my old age .

I've had mine since 2009, one of the first models, doing roughly five roasts a week. I've replaced a heating element, a thermistor, and I've had to realign the drum once, after it began scaping against the rear plate That's it. One person I know had to replace the cooling fan underneath the electronics

So I also think it's good indefintely given minor repairs, since it's basically a commercial sample roaster with standard, easily replaceable parts.

I concur with others too, the M3 seems to last pretty much indefinitely (minus some minor part replacement as needed). I have a 2014 model, the unit had done at least a few thousands of roasts (between the previous owner and myself), and I haven't had to change the elements nor anything else. Though I am keeping a spare set of elements on hand just in case (and had added a TC4-Arduino controller since).

Do you have a MET probe to monitor the temp outside the drum? I usually try to keep my max MET around 500-520F/260-270C (based on Jim's post on Quest many years ago) and think that had helped make sure the probe isn't stressed unnnecesarily.

samuellaw178 wrote:I concur with others too, the M3 seems to last pretty much indefinitely (minus some minor part replacement as needed). I have a 2014 model, the unit had done at least a few thousands of roasts (between the previous owner and myself), and I haven't had to change the elements

Dam little beast still going strong!

It certainly is!

I bought Nunas's M3 two years ago and it's working like a champ!