Problem w ABS, too high temp, stuck in nozzle

Vertex 3D Printer Vertex - Issues while printing
1

Hi,
First, the termistor is/was correct mounted…
I have printed w PLA w/o any problem (may be too high temp. The nozzle drips filament when in “standby”).
Tried ABS for 1st time today.
Loading was OK.
Let it cool down.
Started a print w ABS @ 245.
Didn’t reach 245 without slowing fans down !!!
Started Printing (stopped fans manually to force temp to 245 to get it start) w/o any extruding.
Measured the heat block temp and found it was ~270 deg !!! (explains why it had a hard time to get to 245).
Now I can’t unload ABS filament. It is stuck in the nozzle.
Dismounted the nozzle , measured the termistor resistant @ diff temp.
Impossible to match the termistor against any type in termistortables.h.
Vertex should be #5, but it do not match well. The wanted 245 deg compares well with ~270 in my measured table.
My table show me that I get higher temp with PLA than the settings show (explains the dripping).
The table don’t match with #10 either (that other purpose in this forum).

Can ABS be stucked in the nozzle due to too high temp ???
Or can PLA together w ABS in high temp, stuck the nozzle ??? (did use PLA Before changing to ABS)

Can the problem be that the termistor is “isolated” from the heating part (i.e. the White termistor protection) ?

For me it looks like the temperature measurement do not work well in the Vertex…

Edit… Change from extruder to nozzle, my bad

2

There is definitely a temperature issue with the stock values. I’m printing at 190° for PLA and 225/230° for ABS. With the fan blowing full speed it takes ages to reach 230° so I’ve slowed the fan speed during the heating process.
Loading ABS after PLA shouldn’t be a problem. The reverse could (so I load the PLA after ABS with the ABS settings).

[quote=“largab”]Can ABS be stuck in the nozzle due to too high temp ???
Or can PLA together w ABS in high temp, stuck the nozzle ??? (did use PLA Before changing to ABS)
[/quote]

It usually doesn’t but PLA heated at 270° will burn in the nozzle and definitely clog it.