Strange bed temperature overshoot after E3D installation


I have noticed a strange issue, after I installed my new E3D v6 hotend.
For some strange reason my bed temperature increases after the print has started and remains rising and then slowly drops.
The temperature rise seems to be approx 10C for each print.
My first idea was that I needed to run autotune for the bed, but this did not help.

In this screenshot the bed tempeature overshoot is marked yellow.

I have never seen this with my original hotend, and it only started to happen after I have installed my E3D.

During the captured print I checked the LED of both heater drivers, but only one of them was active (would be the hotend for sure).

I have one theory that might fit, but seems to be a bit far fetched:…
I am printing a small object 20x20mm on the middle of the bed, where if I am not mistaken the bed thermistor is located.
As the bed heater does not seem to be controlled, could it be that the E3D hot end irradiates so much heat that the thermistor picks it up and the reported bed temp starts to rise. Then as the distance between the hotend and the bed increases with each layer, the influence on the bed temperature decreased, hence the drop in temperature.

I have the original K8200 heated bed, with the velleman 3mm glass plate ontop.
The heater is a 12V replacement heater and the thermistor is also a replacement, which I both used with the original hotend as well.
I also ran autotune on the E3D setup, and stored the settings.

Has anyone seen such an effect before ?
And or has an explaination and or fix ?
Because I do not quite now if this is something to worry about during printing.

Best Regards,


Look at where the plastic is being layer down on the bed.
If you are print on the thermistor on the bed this will happen as the plastic be 190C will heat the thermistor.