IBTS acting up!


the other day I was roasting 5-6 back to back roasts. I’ve done that several times before but this time I got IBTS fan-error. Wasnt to surprised since I havent cleaned IBTS/fan for a while. Said and done I removed the housing and I found alot of build up (looking moldy?) on the PCBs. Cleaned it up, made a couple of huffs and puffs into the ibts-fan-hole and put everything back. Error was gone.

HOWEVER, now the IBTS is acting really weird. It pretty accurate (as far as I can tell) in the beginning of the roast, but when temp is geting higher the ibts seems just so stabilize and flatten out (se picture below).

Ideas? I’ve ordered a bunch of spare parts and my goal is to take the machine a part to do a holiday cleaning. It has been through stress test now with all the xmas orders coming in. Is cleaning enough or has anyone seen this behavior before and knows “that ibts needs to go to the recycle pile”.

That’s usually an indication the lens of the IBTS is dirty. Since you cleaned the IBTS fan there’s a good chance you got some of the roasting ‘snot’ (that yellowish-brown dust) from the fan down onto the IR sensor lens or possibly lodged in the view port for the IR sensor.

Not a hard job to clean the IBTS. IIRC the manual recommends alcohol and a cotton swabs. You should clean the walls of the view port as well as the lens (the ‘lens’ is a flat surface- it’s not refractive). The first time takes several passes; future cleanings should go quicker. Don’t reuse any of the swabs. Don’t dip a previously used swab into the alcohol reservoir. When you look at the swabs after cleaning you probably won’t see any contaminant but it’s there. Frustrating when doing the cleaning to not know the job is done but that’s what you have to deal with. Which means there’s trail & error Involved- you have to try the Bullet and see how it compares.

What I think I see in the chart above is typical of what contamination to the IR sensor of the IBTS does… it’s like putting a filter between the lens and the IR source (the heated beans in the drum).



Thanks alot for putting time and effort into answering me! Appriciate it!

Really didnt know the IBTS was that sensetive for contamination but it sure makes sense. Im gonna try the swab and alcohol-cleanse before i change the sensor.

Merry christmas!

Hope it proves an easy fix. And thx for the Christmas greeting!


In case of anyone else having the same issue and is in search for answers:

I inspected with a very bright flashlight the sensor and could confirm there were tiny particles of… something… on the sensor. I did as Bab suggested and used swabs and alcohol for cleaning. Also did a deep clean on everything on the machine.

IBTS is working as intended again. If I had seen those dirt particles beforehand I would’ve said “nah thats fine it wont affect the ibts”… Well… it does.

Keep your stuff clean, Ive added another cleaning day to the routine thats for sure.

Again thanks to Bab, Roast world mvp.


Yes, that is good to know. Just like any camera lens, smudges and spots can look darker