Ninja profile - heat to slow, please check the beans

[hificoffee]

Hi Chris,

The Ninja profile repeatedly fails about two minutes into the roast an onscreen error appears “heat to slow, please check the beans”. if I swap back to classic the roast completes ok. Swapping back to Nija same error I use the recommended 2.6 setting.
I have added the exact supplied cup measure and checked chimney is well seated. I have tried adding in a few more beans though receive the same error code.
Any ideas please, I am interested to try out this profile?

Classic profile is working ok

Thanks,
John

[kaffelogic]

Hi John, we have been testing all roasters with the Ninja profile before shipping, a test that your roaster passed. This message appears if the roaster is running significantly below the profile curve, but I can't think of any reason it would do that. Are you able to post a roast log? This will give me more diagnostic information that will help me determine the cause.

[hificoffee]

Hi Chris

Yesterday’s occurrences was a little strange I could not roast the Guatemala Bean - smaller dense hard bean with the Ninja profile although a roast completed with Ninja with low density larger bean from india. Always using the exact cup amount and chimney securely seated.

I tried increasing the amount of beans a little to the Guatemalan though failed with the error perhaps I should have tried less than the cup amount?

Can environmental conditions cause the error - AC line voltage here was 232v ( I tried turning off other appliances after the error and retried a roast but same error) , warm day, bean density?

Also, this morning makes a mockery of yesterdays results, as switching to the Ninga profile this morning the Guatemala roast completed without error!

update: I attached logs this morning when creating the post, though when I checked back this evening I could not seem them attached.

Thanks
John

[kaffelogic]

I am still trying to work out whether the roaster is being a sensitive little flower and I just need to re-program it to be a bit more tolerant of variation early in the roast - or there is something wrong with yours meaning I will need to replace it and revise our factory QA processes accordingly. Thanks for posting a wealth of data. I'm pretty sure line voltage is not an issue as it is still definitely over 230V (most of our testing takes place at 237V). I will need to spend some time replicating your results to make a final diagnosis which could take me well into next week.

[kaffelogic]

I have identified a specific error with the 'heat too slow' criteria. This only shows itself with certain profiles because it depends on how sharply the profile curve changes slope in the first minute. This has been rectified in firmware version 7.3.5 and I am confident the problem will go away once you update the firmware.

John, I have had a good look at the roaster you returned to me and it is producing the correct amount of air, in other words, there is nothing wrong with it. The problems you were having came from the particular combination of beans, profile, and the above-mentioned bug. The replacement roaster will have been producing a slightly different amount of air, hence explaining its different occurrence rate of the 'heat too slow' message, but both roasters are within the functional range. The profile-following algorithm makes up for the small differences in air between roasters.

It is now possible to calibrate roasters to match air flow more precisely and I will be publishing more information about how to do this in the future, however it is not necessary to do this for general use.

[PQRS]

Hi Chris,
I have had the same issue with both Ninja Profile and Firestarter using Ethiopian beans which are quite small. Firestarter worked ok when I tried larger Nicaraguan beans. I've only got a roast log from the last time it did this. Can't remember which profile i used was either Ninja or Firestarter. The standard profile works fine.
Paul

[PQRS]

Forgot to say I have loaded new firmware.
Paul