thermal runaway error
hi,
I've recently replaced thermistor and heater cartridge of my mk3s printer. since then, I am experiencing thermal runaway error. it happens each time ( 5 attempts up to now) at the start of the layer 4, when the printer fan is at 100%. the screenshot shows the problem. the first two layers are ok ( 215 and 230 degrees), during the third layer, the printer temperature is around 219 degrees to decrease down to 213 degrees as soon as the fan is 100% speed.
it is like if the heater / printer was not able to compensate the temperature drop due to the fan.
any idea what could be the root cause ?
thanks
RE: thermal runaway error
Did you run a PID calibration after replacing everything?
RE: thermal runaway error
yes. I did. the calibration was successful.
RE: thermal runaway error
Did you mount the fan shroud correctly? Perhaps it's cooling the heat block instead of the printed object.
Check the resistance of thermistor and heater with a multimeter - are they ok? ( https://help.prusa3d.com/ja/article/multimeter-usage_2117 )
If at first you don't succeed, skydiving is not for you.
RE: thermal runaway error
During the replacement of the heater and the thermistor, I've also replaced the fan shroud, the old one was not effective anymore after 5 years of printing. I do think I did put the new one at the right position but it is true that with this shroud, the fan is directly cooling the heat block. So I 've replaced it by the mk3s+ fan shroud version that does not have the big hole in the middle. This seems to have fixed the problem.
I don't understand yet how this brand new shroud has triggered this problem.
thanks for the help.
RE: thermal runaway error
that does not have the big hole in the middle.
??? Big hole? Pictures?
RE: thermal runaway error
the mk3s shroud let the airflow coming from the fan hit the heat block located in front of the shroud. The mk3s+ shroud prevents direct airflow to hit the heat block, and drive airflow on the sides and at the bottom to cool the printed part down.
RE:
Did you remove the support section from the shroud?
„For fan-shroud part, please use Prusament ASA / PC-Blend with default settings and 5mm brim if necessary.The fan-shroud STL file includes an inner support rim that needs to be removed after printing. It can be easily removed with needle-nose pliers, a knife, or flush cutters together with the brim. Otherwise, it will block most of the air from coming out. See the corresponding assembly manual chapter to see what the part should look like after removing the inner support.“
(Quote from https://www.printables.com/de/model/88272-i3-mk3s-printable-parts )
If at first you don't succeed, skydiving is not for you.
RE: thermal runaway error
since my printer was not able to print anything before replacing parts, I bought a printed shroud from prusa shop. so it had the support removed.
thanks