Filament problem

Hi there. One of my 3d printers is FlashForge 3D printer. I have printed succesfully a number of models, some reasonably complex. Both extruders were loaded with PLA. Now I wanted to change the filament in one of the extruders to PVA as I wanted to use water soluable supports. For some reason when I try to unload the filament, the extruders start to heat as the screen shows, however, the temperature does not rise as described in the guide. Waited 15 to 20 minutes - no change at all. Followed step by step the instruction without success. I also tried loading filament - exactly the same - no rise in the temperature. When I print - both extruders get heated normally and there has not been a problem printing. Any idea as to why this is happening? This is kind of annoying as I cannot change the fillament. Any help will be very much appreciated.

Flash forge is not Tiertime printer, but have you checked the material temperature on the extruder you are using for PVA? It uses a higher temperature than PLA.