Purge macro prusaslicer issues.

Caveman

I have installed duet wifi on my corexy and try to use prusaslicer for main slicing.
And run into a problem. Purging is not happening because the heater does not heat up until after purging.

This is my start code:
M291 P"Homing all axis" R"Printing.." S1 T2
G21 ; metric values
G28 ; home all
;G29 S2 ; mark if you want to disable mesh grid
G32 ; Run mesh grid compenstion
; Purge extruder
G92 E0 F100 ; reset extruder
G1 Z10 F3000 ; move z up little to prevent scratching of surface
M98 P/macros/Filament/Purge ; Run nozzle purge macro
G1 E-1 F2000 ; Retract 1mm filament
G92 E0 ; reset extruder
M291 P"Printing started !" R"Printing.." S1 T3

This is my macro:
;purge hotend
M291 P"purge started !" R"purging.." S1 T2 ; display msg
G1 Z10 F3000 ; move z up little to prevent scratching of surface
G1 X5 Y70 Z0.3 F5000.0 ; move to start-line position
G1 Z0.3 F1000 ; print height
G1 X5 Y220 F1500.0 E15 ; draw 1st line
G1 X5.2 Y220 Z0.3 F5000.0 ; move to side a little
G1 X5.2 Y70 Z0.3 F1500.0 E30 ; draw 2nd line
;G1 E-1 F2000 ; Retract 1mm filament
G1 Z10 F3000 ; move z up little to prevent scratching of surface
G1 X150 Y150 F6000 ; move to center of the bed
M291 P"purge finished !" R"purging.." S1 T2 ; display msg

Should I add temp setting to macro?

OBELIKS

Is this the whole start code?
Because you are completely missing the temperatures.

I would put this before G32

M104 S{first_layer_temperature[0]-40} ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S{first_layer_temperature[0]-40} ; wait for extruder temp

This way you avoid runny extruder while printer is running mesh procedure.

Then add this before ; Purge extruder

M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp

Phaedrux

You'd have to share a sliced gcode file so we can see the full start gcode with the temp commands inserted by the slicer. You may also be able to use M116 before the purge to wait for temps.

https://duet3d.dozuki.com/Wiki/Gcode#Section_M116_Wait