BB nozzle always dirty

[Ziogianni84 3]

Why does my BB nozzle (loaded with PVA - 220°C) comes out charred after every print?

If you compare it to the AA there's a huge difference, since as you can see (on the right side of the pic) the BB nozzle is covered by a burnt layer of goo.

Edited October 22, 2017 by Guest

[kmanstudios 1,120]

That is the nature of PVA materials. It gets worse as the humidity goes up too.

[Dim3nsioneer 558]

The situation gets a bit less bad when you switch off the prime blob for the BB core as the nozzles deeply dips into that blob (no idea why but I guess this could be fixed). But you need a skirt or brim to have proper priming for the PVA this way.