MINTEMP BED during print (araound end of first layer)
Hello.
Maybe someone can help me pinpointing the issue:
Am aware that it could be the sensor/wire, but heating the bed, wiggling the wire, I never see any odd readings on the display.
I thought it might have something to do with which temps slicer sets for first and additional layer, but since the issue happened with PLA and PETG (where PLA has no temperature difference for first layer in the slicer), I am not too sure anymore.
Also the log (what I could get trough Octoprint) does not really show a temp issue, even though the error is triggered. So I wonder if something else might be totally wrong here. Not every print, just sporadic.
Here is the log from when it failed the last time:
2026-03-27 00:50:02,730 - octoprint.util.comm - WARNING - Received an error from the printer's firmware: Heaters switched off. MINTEMP BED triggered! | Last lines in terminal: | Send: N65118 G1 X73.541 Y50.83 E.04556*97 | Recv: ok | Send: N65119 G1 X73.215 Y50.102 E.05826*85 | Recv: ok | Send: N65120 G1 X73.04 Y49.323 E.05832*97 | Recv: ok | Send: N65121 G1 X73.023 Y48.525 E.0583*102 | Recv: ok | Send: N65122 G1 X73.164 Y47.74 E.05826*110 | Recv: ok | Send: N65123 G1 X73.544 Y46.843 E.07116*92 | Recv: ok | Send: N65124 G1 X74.022 Y46.176 E.05994*86 | Recv: ok | Send: N65125 G1 X74.608 Y45.635 E.05825*81 | Recv: ok | Send: N65126 G1 X75.291 Y45.221 E.05834*86 | Recv: T:210.5 /210.0 B:60.1 /60.0 T0:210.5 /210.0 @:80 B@:66 P:0.0 A:36.6 | Recv: LCD status changed | Recv: Error:Heaters switched off. MINTEMP BED triggered!
I wonder: Would the Prusa firmware cancel a print immediately, if a sensor is showing perfect values but for some weird reason there is a hickup, and for a second or so crazy values are received (which might not even show in the log)? Would think that if value is out of the ordinary for a second, or so, ignore the value and treat it as a faulty read?
Am on the current firmware 3.14.1-8237
Octoprint Version 1.11.7
RE:
Its probably a faulty wire still even if you havent found it it but could also be a temp drop.
The very first layer on nearly all filament profiles has zero part fan. Then after the first layer the fan kicks on. Some filament profiles start it at layer 3. I suspect your part fan is kicking in and cooling the bed more than it can cope with. Generally the part is placed in the middle by the slicer and guess where the thermistor for the bed is located, thats right, in the middle underneath.
You could alter the filament profile to make the Full fan speed at layer setting something like 3-5 (its a red/expert level setting). Or for a small part position it away from the middle as an experiment.
And yes once it goes to mintemp its an instant cutoff as thats a safety function.