S5: Nozzle offset probe failed... beacuse of a high temperature???

[yetAnotherUsername 4]

I've just spent nearly 3h trying to start a print and getting the famous "The difference between height of both print cores exceeds realistic value". Actually it worked the first time, but the print did not succeed due to no filament flow (using original and new Ulitmaker Tough PLA - already has signs of grinding...). The next 30-so times it did not work, mostly failing both heads, sometimes only one (i.e. the bed movement stops a few mm before touching the head). I have cleaned the glass (plus the alu bed below) and the sensor, twice recalibrated the bed z offset, recalibrated the heads switch (pointless for me but was following the instruction from the linked thread), replaced heads multiple times, and finally removed the screws and checked the cables themselves. Nothing has helped, nothing - S5 was still failing the test...!

 

Actually it's the 2nd time this happened to me already (and the printer is seldom used...) but the 1st time it eventually "started to work again". So I decided to check whether is has something to do with the temperature of the head compartment and bingo - after letting it cool down for about 5-10 min it passed the test and started printing!

 

What is really frustrating about this is that I didn't even want to use dual extrusion and yet every time I print the stubborn printer (or its makers) makes me go through the test (even though the 2nd filament is not even loaded). The printer refuses to print without the 2nd head as well (why?!).

 

So in conclusion

BUG: nozzle leveling test fails when heads compartment is too warm (so trying to quickly restart a print after a failed test is likely to fail).

 

REQUEST: please allow users to remove the 2nd head and thus not go through the nozzle leveling test for each print.

 

By the way: is it my impression or the nozzle test is done always in the same spot? If so no wander that eventually it fails since the bed gets more and more "dirty" in that spot...

 

 

Greg

 

P.S. You can test it on your printer: simply abort a print just after the nozzle offset test and then immediately start it again.

 

Edited February 9, 2021 by yetAnotherUsername
Typo in the title & added P.S.

[civileng 1]

I am experiencing this same issue. I have to wait for the build plate to completely cool down before the Ultimaker lets me do a reattempt. I've followed all the suggested steps on the website with no success.