diff --git a/src/libslic3r/GCodeWriter.cpp b/src/libslic3r/GCodeWriter.cpp
index cfd3a45cd2..3e09ad89c9 100644
--- a/src/libslic3r/GCodeWriter.cpp
+++ b/src/libslic3r/GCodeWriter.cpp
@@ -687,7 +687,7 @@ std::string GCodeWriter::lift(LiftType lift_type, bool spiral_vase)
         //BBS
         double above = this->config.retract_lift_above.get_at(m_extruder->id());
         double below = this->config.retract_lift_below.get_at(m_extruder->id());
-        if (m_pos.z() >= above && (below == 0 || m_pos.z() <= below))
+        if (m_pos.z() >= above && m_pos.z() <= below)
             target_lift = this->config.z_hop.get_at(m_extruder->id());
     }
     // BBS
diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 6e3c6aa548..394a5cc1b6 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -2607,6 +2607,7 @@ void PrintConfigDef::init_fff_params()
     def->tooltip    = L("Z hop will only come into effect when Z is above this value and is below the parameter: \"Z hop upper boundary\"");
     def->sidetext   = L("mm");
     def->mode       = comAdvanced;
+    def->min        = 0;
     def->set_default_value(new ConfigOptionFloats{0.});
 
     def             = this->add("retract_lift_below", coFloats);
@@ -2614,6 +2615,7 @@ void PrintConfigDef::init_fff_params()
     def->tooltip    = L("If this value is positive, Z hop will only come into effect when Z is above the parameter: \"Z hop lower boundary\" and is below this value");
     def->sidetext   = L("mm");
     def->mode       = comAdvanced;
+    def->min        = 0;
     def->set_default_value(new ConfigOptionFloats{0.});