Set up: (2) AMS 2 Pro, (1) AMS HT. All set to drying mode (one of the AMS 2 Pro has its own power supply). Both AMS 2 Pro were set to PLA, the AMS HT to ABS. One of the AMS 2 Pro went way over temp; it was set to 45 C for 12 hours, but got to 64 C before I terminated that. Here is a pic for when it…

Looks like this bug: [image] Overshooting set temperature whilst drying filament AMS 2 Pro The past few months I have noticed the AMS 2 Pro having a “thermal runaway” at least on 3 occasions. Could have been more as there are occasions where I set it on dryin…

Ah, thank you, that indeed sounds the same, more or less. Yah, mine was definitely not runaway, it did actually stabilize at 64 C or so, it just happily controlled the temperature to the wrong set-point as far as I could see. I’d give extremely high odds of firmware bug when multiple AMS are drying …

AMS 2 Pro over temp for drying

Bambu Lab AMS AMS 2 Pro

krellboy July 19, 2026, 5:23pm 2

Looks like this bug:

And it’s not “thermal runaway”, but read the thread.