What is the problem?
If got some problem with thermal runaway with my 2 months old Ender 3 V2. First I got the thermal runaway error but then I got the "Printer halted. kill()" message. So I investigated a little bit and tried to reproduce it. I need to say, at the moment I have no silicone sock, my new one arrives in a few hours
And I was succesfull, I heat the hotend to like 200°C and then set it to 0°C. After a few seconds I reactivate it to 200°C and then I get an error after 10 receives. I think it's, because it needs too long for reheating and the temp is still falling. Is this just because I don't have no silicone sock or is it also the firmware?
Additional information about your setup
printer: Ender 3 V2, firmware: I've got it from creality. It's this one
Marlin-2.0.1-BL-Touch – V1.1.1(without adapter board)
terminal.log (3.2 KB)
The lack of the silicone sock can definitely influence how heating the hotend performs. If you haven't run a PID tune, I'd recommend that.
And, if you've been working on the hotend at all, check that the thermistor is secured properly. It needs to be in the well in the side of the heater block and the screw holding it in place should be tight enough that it won't move around. Just don't tighten it past that, or it can break the wires.
edit: Also, with the way that PID heating is configured, your reproduction steps are creating a 'perfect' set of conditions, more or less. By default, the heater will be turned on 'full' until it's within 10 degrees or so, then it starts to back off and use less power.
The thermal runaway algorithm basically watches the temperature when the heater is on and if there's not an increase within a specific amount of time, it triggers the runaway alarm.
So, by heating the hotend up to temperature, turning the target off and then back on, you've caused the heater to start in the 'not full power' range, but without the sock it's probably losing more heat than the PID values are tuned for, so it can't actually keep up. When the thermal runaway code sees the temperature isn't increasing fast enough, it sets off the alarm.
I printed a temp tower today for my new filament and with the sock the error is gone. On 230°C i get like ±1°C fluctuation. But at 200°C I only get like ±0.2°C fluctuation. So it's pretty stable now.
Edit: Thanks for all this valuable information. At the moment it works but I think I'll do a PID tune. At the very least, as soon as I buy a new hotend.