Bullet is going over 245°C in PH

Hello everyone!!

I’m having a problem these last weeks with my Bullet V2 during PH with last stable firmware

I usually roast 1200g batches so I always preheat to 310 °C IBTS.

While the Bullet preheats, I’m usually around preparing my roasting session, weighing batches, until the Bullet calls me to charge.

But these last weeks, when preheating, the Bullet throws the error when it exceeds 245°C with the bean probe all the time when is preheating, It appears that the Bullet is intentionally seeking to overheat.

I cleaned the Bullet thoroughly, cleaned the glass of the IBTS, cleaned the bean probe, all the chaff collector, the propeller and the metal mesh very well with espresso cleaner. Also I calibrated the fan few times.

The Bullet continues to overheat, The only thing I have seen that works to avoid the error is to remove the chute plug when it is at 235°C, like that the temperature get stable.

The ambient temperature doesn’t exceed 22°C.

Any tip/idea?


Contact Aillio Support and start a Trouble Ticket.


This usually happens when the IBTS sensor is dirty. Your drum might in fact be much hotter than it should, cause the bean probe to overheat too.

Hi @bab , I will do that :slightly_smiling_face:

Hi @jacob , I thought the same so I cleaned the IBTS and the small fan well, both were very clean before and didn’t made any difference before and after about that problem.

I recall @bradm saying the same thing but he tried a 2nd or 3rd time and suddenly had a shift in temps on IBTS. Same issue? I have no idea. But it may be worth it to try again. I came away from his experience thinking perhaps there’s a clear coating in the IR sensor lens that is not clear to IR after being heated wtih roasting temps.

And alcohol doesn’t readily dissolve coffee roasting ‘stuff’ on any surface where I’ve tried it. Seems to take repeated applications.

Btw… good call cleaning the IR sensor cooling fan.


Alcohol doesn’t clean coffee, I used Roaster Sprayz with a cotton swabs that is made for that.

I’ve never had any problem with overheating, but I only preheat in the 210C range. I did have one roast where the IBTS curve suddenly decreased about 50C late in the roast, then recovered about 30 seconds later. I attributed this to a large flake of chaff temporarily obstructing the sensor’s view (very chaffy bean). Hasn’t happened again.

I agree but I believe Aillio want you to use alcohol. Citric acid cleaners may be an issue for the IR sensor but that’s speculation on my part (I’m thinking about potential effects on insulation of the wires).


It is the software 3.2.4
Roasted 1200 grams the other day without problems, roasted today 1000 grams after updating, with the result that the temp rise to over 245 degrees. Roasted 500 grams subsequently without any problem
It is the software (3.2.4) that teases not a dirty IBTS Probe

Maybe you could come up with the truth

1200 grams is 20% more than the official capacity of the machine.

Maybe you can get away with it sometimes, but I’m not surprised to hear that it behaves strangely.

I think you might be overdoing it.

But the 1200 vent good roasted on Ver 3.2.3 the 1000 went wrong rosted on Ver 3.2.4
can you explain it

can you explain it

No. But I assume Aillio is not doing a lot of 1200 gram test runs.

So something may have changed, something that improved roasting for normal size charges, perhaps.

(@lav) who is employed by aillio Roast 1200 gram all the time see his profile

Oh, I didn’t realize that.

What is the fan speed on the IBTS device? (You can check that by clicking the (I)nfo button in the upper right of the roast time software while roasting. The fan speed should be in the range of about 14000 to 17000 rpm. I had an issue with the overheating error and it was due to the fan no longer maintaining speed (ended up replacing it to fix the problem).

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I had a similar drop in temp mid roast. Sent the profile to support for a probable cause. Was thinking on the same lines of some chaff obstructing the IBTS. Reading your reply corroborate my thought. Thank you.

I did see a report somewhere of a small bean getting lodged in the IBTS window which I guess would blind it. As they say, very very small but non-zero chance…

Hi @sven , thanks for your suggestion, I checked that already and is at 15000 always, doesn’t move at all, also I cleaned the fan when the error started to happen.

@cash0612 It was my first suspicion, so I thoroughly cleaned the Bullet, including the IBTS and the fan, which were pretty clean. Didn’t help.