Limit preheat parameters based on all nozzles

Marlin/macros.h

@@ -126,8 +126,10 @@
 
 #define CEILING(x,y) (((x) + (y) - 1) / (y))
 
+#define MIN3(a, b, c)    min(min(a, b), c)
+#define MIN4(a, b, c, d) min(min(a, b), min(c, d))
 #define MAX3(a, b, c)    max(max(a, b), c)
-#define MAX4(a, b, c, d) max(max(max(a, b), c), d)
+#define MAX4(a, b, c, d) max(max(a, b), max(c, d))
 
 #define UNEAR_ZERO(x) ((x) < 0.000001)
 #define NEAR_ZERO(x) ((x) > -0.000001 && (x) < 0.000001)

Marlin/ultralcd.cpp

@@ -1788,11 +1788,24 @@ void kill_screen(const char* lcd_msg) {
   }
 
   void _lcd_control_temperature_preheat_settings_menu(uint8_t material) {
+    #if HOTENDS > 3
+      #define MINTEMP_ALL MIN4(HEATER_0_MINTEMP, HEATER_1_MINTEMP, HEATER_2_MINTEMP, HEATER_3_MINTEMP)
+      #define MAXTEMP_ALL MAX4(HEATER_0_MAXTEMP, HEATER_1_MAXTEMP, HEATER_2_MAXTEMP, HEATER_3_MAXTEMP)
+    #elif HOTENDS > 2
+      #define MINTEMP_ALL MIN3(HEATER_0_MINTEMP, HEATER_1_MINTEMP, HEATER_2_MINTEMP)
+      #define MAXTEMP_ALL MAX3(HEATER_0_MAXTEMP, HEATER_1_MAXTEMP, HEATER_2_MAXTEMP)
+    #elif HOTENDS > 1
+      #define MINTEMP_ALL min(HEATER_0_MINTEMP, HEATER_1_MINTEMP)
+      #define MAXTEMP_ALL max(HEATER_0_MAXTEMP, HEATER_1_MAXTEMP)
+    #else
+      #define MINTEMP_ALL HEATER_0_MINTEMP
+      #define MAXTEMP_ALL HEATER_0_MAXTEMP
+    #endif
     START_MENU();
     MENU_BACK(MSG_TEMPERATURE);
     MENU_ITEM_EDIT(int3, MSG_FAN_SPEED, &lcd_preheat_fan_speed[material], 0, 255);
     #if TEMP_SENSOR_0 != 0
-      MENU_ITEM_EDIT(int3, MSG_NOZZLE, &lcd_preheat_hotend_temp[material], HEATER_0_MINTEMP, HEATER_0_MAXTEMP - 15);
+      MENU_ITEM_EDIT(int3, MSG_NOZZLE, &lcd_preheat_hotend_temp[material], MINTEMP_ALL, MAXTEMP_ALL - 15);
     #endif
     #if TEMP_SENSOR_BED != 0
       MENU_ITEM_EDIT(int3, MSG_BED, &lcd_preheat_bed_temp[material], BED_MINTEMP, BED_MAXTEMP - 15);