What’s the hottest room temperature you can roast P9 at?

Trying to figure out what range you can stable roast P9 in?

At 88F room temp, I get overheating Error code 32.

I’ve found that a cooler room helps with the overheating error, but then the roasts come out lighter at the same IBTS and BP specs. Roasts aren’t fully roasted. Paper and bland flavor. Increasing the room temp seems to help with depth of flavor, but only when the roast doesn’t Error 32.

Also, how big is the space you roast in? I assume a smaller room cannot dissipate heat as well as a larger room, so maybe mention approximate room dimensions too.

88F is 31C that has been my room temp lately, as it seemed to be the threshold, but now that I am attempting 900g batches, I’m using P9 longer and maybe worse, preheating a lot hotter.

You might try aiming a small fan at the front of the Bullet. There is an air inlet that will cool down the IBTS fan sensor. I was getting an error 42 and the IBTS fan temp was going over 80c. After aiming a fan at the inlet, The temperture dropped to 38c in a matter of minutes.


I’ll try that out.

Is that the IGBT1 reading?

I’m finding it a little frustrating because the Bullet is so sensitive to environmental temperature, that I want my temps to be more similar year round, and in the Summer, I can have 30C or 85+F temps without using an Air Conditioner to go cooler.

The idea is to have a “green” energy roaster, but it requires a lot of energy in the Summer to keep cool. (In the winter the roaster itself does some of the heating, so I haven’t found the electricity to be much for the heating as the cooling)

Does anyone roast in 30C or 80F+ room temps?

Anyone roast in 90F room temp?

That is the IR Ambient from the info screen

I also have a fan aimed at the belly to keep the main PCB temp from overheating. I also installed a little aluminum flashing to keep the bowl cooling fan from pushing hot air and snot off of the main PCB.


Wildly different readings from mine:

Is yours in standby mode with those stats?

I believe my screenshot was taken with P9 applied, hence the voltage drop to 116v

That screen shot was not from my roast. I just plagarized the photo from another thread.

What are your stats?

Here is a photo of the Info screen from a roast from around 2 months ago.
I had a fan pointed at the IBTS air entrance. That is why the IR Ambient temp is so low.

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What was your approximate room temp? Those readings are all a lot cooler than mine.

I had my room I heated this time, or only heated by the roaster, and initially that was a stable 15F degrees cooler.

So in Celsius I was now at 24C room temp, and my IGBT1 went to 92C with 2 USB fans.

I briefly used one of the fans on the front plate, directed at the vents for the IGBT SENSOR FAN, but I saw no change in that. It hovers around 62C.

IGBT1 is the main one that’ll cause an error 32 code, and at 100C it is a shutdown. 92C was cool enough that I ran P9 for 5minutes and no shut down.

The main issue is learning how to roast in cooler air temps. It changes the way my roasts developed, and I had to apply new heat application, so I’ll do some cupping and find out if my changes were good or not. but that isn’t the issue, as I was not too happy with my 450g roasts anyway. my main thing is now being able to roast 1Kg, and that is exciting! So far it looks promising.

Also, far less hot plastic smell. I only got the smell once, so the room temp plays a part in the plastic warping and off gassing. I think just for your health it is best not to breathe in plastic fumes.

So, I’ll have to figure out a solution for the summer hear, I guess.

It is sad, because the roasts are otherwise better with the warmer room temp air.

Here was my setup and stats with a room temp 75F or 24C

With the IGBT1 temp at 92C, I felt a lot better having firmware 610.

However, my PCB and R ambient temps didn’t seem to change with a cooler room. They looked the same as before.

I’ve actually had cooler IR ambient temps with a hotter room before.

I live in Southern California. The ambient temperature in the room doesn’t change much summer to winter. It is usually in the 18C to 24C range. (65F to 75F) humidity is normally between 10% to 30%.
The room where I roast is not heated or cooled.
I haven’t noticed much difference in my overlay curves and cuppings, summer to winter.
I haven’t paid much attention to the IGTB1 when roasting. I will have to watch that. Actually: I am not sure what the IGTB1 is measuring. Is that the raw temperature from the IBTS?

When I point a fan at the front of the Bullet, the IR Ambient will drop from 65C down to 38C in just a few minutes. Something that doesn’t make sense to me is that the PCB temp will also drop a few degress.

I never smell “hot plastic” that would worry me.

Here is a snapshot of my current setup. I mounted a fan to the bottom of the PCB guard. I also mounted some aluminum roof flashing to keep the heat and snot away from the PCB.
The white “sock” collects the chaff and helps the beans cool faster. I removed the white filter inside the cooling bowl housing.


IGBT1 is what causes the dreaded ERROR 32 Power off (or P0), when it hits 100C. It is also the sensor that your computer fan is cooling under the roaster.