Nozzle needs to be changed if it gets blocked due to dust accumulation, or after consumption of one filament spool.
A. Changing the extruder Nozzle
Caution: Before changing the nozzle please ensure the extruder temperature (Heat Extruder) is set to off so that the nozzle is cold in nature
Heat up the extruder so as to retract the filament from the extruder.
Once the filament is removed from the top of the extruder, switch off the extruder heat switch from Repetier and wait for the nozzle to cool down
Unscrew the grub screw as shown below from both the side of the block
Remove/pull downwards the nozzle from the block as shown below
Push back up the new nozzle along with the telfon tube as show below
Once inserted properly, tighten up both the end grub screw holding the nozzle firmly towards the block as show in the below image
Now load the filament as per the filament loading procedure and also carry out the extruder calibration procedure to ensure the nozzle is well fitted