diff --git a/src/libslic3r/GCode/WipeTower.cpp b/src/libslic3r/GCode/WipeTower.cpp
index c43a3df1cd..0280212a1c 100644
--- a/src/libslic3r/GCode/WipeTower.cpp
+++ b/src/libslic3r/GCode/WipeTower.cpp
@@ -1242,6 +1242,8 @@ void WipeTower::plan_toolchange(float z_par, float layer_height_par, unsigned in
 	// this is an actual toolchange - let's calculate depth to reserve on the wipe tower
     float depth = 0.f;
     float width = m_wipe_tower_width - 2 * m_perimeter_width;
+    if (width <= EPSILON)
+        return;
 
     // BBS: remove old filament ramming and first line
 #if 0
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 6f5c15d848..d850e5ba52 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2822,7 +2822,7 @@ void PrintConfigDef::init_fff_params()
     def->label = L("Prime volume");
     def->tooltip = L("The volume of material to prime extruder on tower.");
     def->sidetext = L("mm³");
-    def->min = 0;
+    def->min = 1.0;
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloat(45.));
 
@@ -2846,6 +2846,7 @@ void PrintConfigDef::init_fff_params()
     def->label = L("Width");
     def->tooltip = L("Width of prime tower");
     def->sidetext = L("mm");
+    def->min = 2.0;
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloat(35.));