It is a little too early to know if the over heat issue is resolved, but initial roasting is somewhat positive in that regard.
But I still have weird airflow issues. I just upgraded to RT4, and so I probably should have done the fan calibration before roasting. But i only wanted to change one thing at a time. Anyway, lesson learned, so I’ll do the calibration tomorrow and see what happens.
Is it normal, after FC that the main vent is mostly a wet smoke, and has a slightly asking smell? Like cigarette ash in a sauna? I seem to recall that part of the roast being sweeter and cleaner before. Any one willing to stick a q tip into the vent stream and then smell it?
Oh, the overheat issue fix has also reduced the plastic and rubber smell.
However, my airflow temp, the convective stuff, has dropped 20F degrees, so I have to learn how to roast with air that is 20degrees cooler that it was before. (Drum hotter, air cooler, so same IBTS and Bean Probe temps, but different air temps. )
Drinking a cup of coffee that is so antagonizingly almost good, it is maddening. There is an aspect of the roast that yields syrupy and almost caramel flavors, but then these raw and even baked or steamed flavors with a bitter paper accent are also there.
I cannot remember the last time I had a good roast. Early days I got nice sweet roasts of caramel, and then one day, everything lost flavor, and I thought maybe I stored the green wrong. But after all this time, I think something happened to the roaster, and none of my fixes are fixing it. One of the fixes was increasing room temp, but then I had overheating issues, so now I cooled the room, but now my roasts are lighter and still steamed smelling. Even at F5. So maybe it isn’t that 1lbs is the worst, but that my bullet has developed an issue, or the remedy on remedies has created an invisible issue? I’ve gone back to the basics, and trying things out, but not super optimistic about the batches I saw yesterday. But proof is in the cup, as they say.
I think I figured out part of the plastic and rubber burning smell. Something I figured would have been thought out in the design, but maybe I’m using it wrong.
So in order to catch the beans in the cooling tray, I have the cooling bowl maybe 1cm under the roaster. This maximizes the catching radius a little better and prevents dozens and dozens of beans from bouncing out, but the heat from the beans rises and then that heat goes up under the Bullet and I smell a plastic burning smell. I’m assuming it is because all the hot air from the beans is so great that some of it gets sucked into the cooling fan for the heating elements, which are mounted on plastic. Or maybe just the plastic fan is affected. Idk.
I had eliminated other plastic smells before finding that one, so it wasn’t the only one, just one I hadn’t really considered.
Anyway, I pull the cooling bowl away from the roaster a bit more than before, and that seems to help, but now I need a fancy lip like some of you fine roasters have made.
I am lucky that I don’t think I’ll need a new board. Was just inadvertently directing heat and reducing airflow to parts of the roaster. Tech support was gracious in considering warranty repair, but I prefer to avoid that.
At first I struggled a lot with the new requirements, and roast quality suffered heavily, other than less burning plastic and not more heat failures, so it was definitely a step in the right direction, just new territory.
My roasts came out pretty unusable. Seems there is potential there, but what do you guys do for fan settings? I try F3 and it is kind of steamy, and F5 is cleaner but then the beans are undercooked. And then I try P9, but that heat constantly seems to reduce sweetness and subtlety, and make for a more simplified and dull tasting roast? I’m still new to 2lbs/900g, but yeah, I like some aspects and dislike others. Mainly liking the improve sense of uniformity, but disliking my current ability to roast these weights.
I still trip the overheat failure at P7 if I don’t use the external usb fan. that is kind of insane to me.
I’ve made my usb fan more efficient and it does a nice job now, but I feel like they are wasteful of the heat, and will cool/slow the roast a few degrees over 10minutes. So I dislike the usb fan just working against the heat trajectory. Plus, it is bad for the environment to be heating and cooling the same thing at the same time.
I’ve got a new fan on the way. Not sure if I still need it, but bought it a week ago when i hadn’t modded my current fan. I’ll let you know how it works. I have some ideas how to use it, and hoping it proves useful.
For fan, my experience has been for a v1R2, 1lb/0.5kg on a P6-P5-P4 or P7-P5-P5 profile, I can go to around F4 and it still seems like I’ve getting decent convective heating of the bean mass. Stepping to P5 is going to start dropping ROR faster, which I’ve tried using as a tool to prevent runaway ROR at the end of my roast.
I haven’t done controlled experiments on this, though; it’s only conjecture. Andrew Coe’s roast profile lends credence to what I believe, though. If you look at his profile, the entire roast (0.5kg) is blowing at F5, but the first half of the roast is P9-P8 followed by steady power cuts to P3. PH is around 250 which seems pretty middle of the road for half a kilo, but all that energy at the start allows him to run a higher than normal airflow w/o killing the ROR.
For high power roasts, I position my auxiliary cooling fan so that it sits right under the IGBTs at the back of the induction board, so that air should flow up into the board and dissipate heat out to the sides. Other thing I make sure to do for any roast is to rotate my cooling tray 90 degrees so that it vents out to the right, instead of blowing hot dirty air right into the induction board right after the roast completes.
Do you watch your IGBT temperatures in the info window while roasting?
Yeah, I have my bowl fan directed towards the side. I It is the heat rising directly from the beans right after dumping. The edge of the bowl being under the door is just enough to allow that heat to rise up into the plastic or something. Not sure exactly. Bu I found i I pulled the bowl out just a centimeter, I didn’t get a burning plastic smell. But I spilled more beans so I’ll need a lip.
My issue is everytime I try to DIY a fix, it never seems like the machine likes operating out of spec, so I am hesitant to implement changes.
Hmm, the problems you’re running into don’t seem to be normal. If you purchased your Bullet from Aillio or an authorized reseller, and you’re in warranty and are being offered warranty service, consider taking them up on it, unless you absolutely can’t afford to be without the roaster for a bit.
My feeling is that Bullet has quite good build quality for a low-volume product that has a bit more complexity than a gas roaster. But as it is low volume and moderately complicated, it possible that you do have one that is out of spec, and there’s no reason you should suffer with that.
I’d take them up on it if needed, but we’re still exploring fixes. They said my overheating issue was normal now.
Idk, i don’t know what normal is, but I think P7 should be ok without a secondary USB fan. but if my room is 80F then under the roaster will be in the 90’sF. I dislike that a lot. But tech support is saying that is normal? Idk.
But yeah, my issues with P7 causing heat failure was from the beginning, I think I have posted about it on the forums before. But if they say it is normal, then getting a new board would just be an unnecessary expense for aillio. I’d like to try a different machine though and find out.
My guess is that my machine is a little sensitive, but the airflow issues caused an issue on top of an issue, which may not have been all that bad, but when they start doubling or tripling up, things compound and tracing issues gets complicated.
What data are you gathering in your troubleshooting?
I have some holiday roasting where I’m going to need to use P7 for the first part of the roast. Again if I remember, I can hook up the kill-a-watt and get voltage, current, IGBT temp, and induction board fan speed readings at P7 for whatever ambient temp it is on that day. That should get you some “other machine” datapoints.
P9 pulls 1600w
info RT4 is 117v power source
Power cable gets warm enough to make the rubber softer around the cable, but not especially hot or excessively warm, just not as cold and hard as the opposite end.nothing else in the area gets as warm though. So it does feel almost certainly like it is coming from the connection.
Ambient air temp under roaster near board is 95F, but room is cooler, so I have seen temp drops on the IBTS if I move from one part of the room toward the roaster, “carrying” cooler air by a couple degrees and that can cause a hiccup in the start of FC.
Replied above, I keep hitting the wrong reply button
My circuit is a 20amp, according to the breaker box, but I haven’t done any sleuthing to confirm the accuracy of that. and it is dedicated to the Bullet, and not shared when roasting.
This is how far I put the cooling bowl under the door to catch more beans, I doubt I am doing much different from others, but the heat rises from the hot beans in the bowl and a plastic smell emits from somewhere. I already ruled out one, as not being the bullet, but some of them are. Like the Chaff box gets very hot, too hot for plastic or rubber, and the rubber gasket on the ventilation just before the chaff box gets almost melts, and have some shape change. And I have identified that smell.
The two plastic smells I am not entirely sure about is the rubber belt for the drum, and the induction area there is a fan and more plastic near the cooling tray.
P9 seems to kill flavor and cause a slight plastic smell, and my P9 roasts faster than COE’s trajectory, so it may be a success problem.
I have roasted three back-to-back 1KG batches twice a week without issue. I direct a fan on low towards the board to avoid overheating, and that is all that I find necessary to avoid any issues.
Interesting that this seems to be an anomaly as I peruse this thread.
