Bed and nozzle temps read too high cold, and nozzle too high when hot
 
Notifications
Clear all

Bed and nozzle temps read too high cold, and nozzle too high when hot  

  RSS
Blackbird351
(@blackbird351)
Eminent Member
Bed and nozzle temps read too high cold, and nozzle too high when hot

I did not notice this until I set up my MK3 next to my MK2s (plus I am used to F not C) and it did not seem to affect most prints (now that some of the filaments are getting older, they don't seem to like the cooler temps). At room temp, the MK2 reads 29C on both the bed and nozzle. The MK3 reads 20C on both.
The room is around 20C so the MK3 is correct.

I also have an IR camera and verified the MK3 bed is indeed 20C, and the MK2 bed is not 29C, but 20C.

I preheated the MK2 to 215 & 55. When the display got to 55C the bed was 55C using the IR camera. The hottest spot on the nozzle I could find read 182C.

Bumped the settings to 255 and 100. Bed showed 100C on the display and read 100C with the camera. The nozzle read 220.

Hot, the nozzle is getting to about 85% of set temp. Cold the nozzle and bed are about 71% of displayed temp.

This is really strange behavior and i am trying to make sense of it. Thermistor? Firmware?
Has anybody else seen this? Any thoughts?
Thanks.

Posted : 03/03/2018 9:53 pm
Blackbird351
(@blackbird351)
Eminent Member
Topic starter answered:
Re: Bed and nozzle temps read too high cold, and nozzle too high when hot

I should add that I have the MMU on the MK2s, so I am running that firmware.
Thanks.

Posted : 03/03/2018 9:54 pm
Zinga
(@zinga)
Trusted Member
Re: Bed and nozzle temps read too high cold, and nozzle too high when hot

I also noticed this when I switched out my hotend thermistor for the PT100 and my temps at idle were 18C (room temp) for the hotend and 26C for the bed. After some searching I found a thread somewhere that it was normal for the room temp to be off since they're calibrated for the higher temperatures. IR thermometer does confirm my bed thermistor is reading accurately at 80C.

Not sure about your hotend, maybe the thermistor is getting that hot inside the heater block and the outside of the heater block is cooler?

Posted : 04/03/2018 8:25 pm
Share: