diff --git a/src/Afterburner/src/Utility/BTC_JSON.cpp b/src/Afterburner/src/Utility/BTC_JSON.cpp
index 5a6ed56..cdc51af 100644
--- a/src/Afterburner/src/Utility/BTC_JSON.cpp
+++ b/src/Afterburner/src/Utility/BTC_JSON.cpp
@@ -32,6 +32,7 @@
 #include "../cfg/BTCConfig.h"
 #include "macros.h"
 #include "../Protocol/Protocol.h"
+#include <string.h>
 
 char defaultJSONstr[64];
 CModerator JSONmoderator;
@@ -289,17 +290,15 @@ void interpretJsonCommand(char* pLine)
     }
     else if(strcmp("LowVoltCutout", it->key) == 0) {
       float fCal = it->value.as<float>();
-      if(fCal != 0) {
-         bool bOK = false;
-         if(NVstore.getHeaterTuning().sysVoltage == 120)
-           bOK = INBOUNDS(fCal, 10.0, 12.5);
-         else
-           bOK = INBOUNDS(fCal, 20.0, 25.0);
-        if(bOK) {
-          sHeaterTuning ht = NVstore.getHeaterTuning();
-          ht.lowVolts = uint8_t(fCal * 10);
-          NVstore.setHeaterTuning(ht);
-        }
+      bool bOK = false;
+      if(NVstore.getHeaterTuning().sysVoltage == 120)
+        bOK |= (fCal == 0) || INBOUNDS(fCal, 10.0, 12.5);
+      else
+        bOK |= (fCal == 0) || INBOUNDS(fCal, 20.0, 25.0);
+      if(bOK) {
+        sHeaterTuning ht = NVstore.getHeaterTuning();
+        ht.lowVolts = uint8_t(fCal * 10);
+        NVstore.setHeaterTuning(ht);
       }
     }
   }
diff --git a/src/Afterburner/src/Utility/NVCore.cpp b/src/Afterburner/src/Utility/NVCore.cpp
index d91cf76..c1df88c 100644
--- a/src/Afterburner/src/Utility/NVCore.cpp
+++ b/src/Afterburner/src/Utility/NVCore.cpp
@@ -23,6 +23,7 @@
 #include "NVCore.h"
 #include "DebugPort.h"
 #include <functional>
+#include <string.h>
 
 #define INBOUNDS(TST, MIN, MAX) (((TST) >= (MIN)) && ((TST) <= (MAX)))
 
@@ -45,7 +46,7 @@ CESP32_NVStorage::validatedLoad(const char* key, char* val, int maxlen, const ch
 }
 
 bool
-CESP32_NVStorage::validatedLoad(const char* key, uint8_t& val, int defVal, std::function<bool(uint8_t, uint8_t, uint8_t)> validator, int min, int max, uint8_t mask)
+CESP32_NVStorage::validatedLoad(const char* key, uint8_t& val, uint8_t defVal, std::function<bool(uint8_t, uint8_t, uint8_t)> validator, uint8_t min, uint8_t max, uint8_t mask)
 {
   val = preferences.getUChar(key, defVal);
   if(!validator(val & mask, min, max)) {
@@ -61,7 +62,7 @@ CESP32_NVStorage::validatedLoad(const char* key, uint8_t& val, int defVal, std::
 }
 
 bool
-CESP32_NVStorage::validatedLoad(const char* key, int8_t& val, int defVal, std::function<bool(int8_t, int8_t, int8_t)> validator, int min, int max)
+CESP32_NVStorage::validatedLoad(const char* key, int8_t& val, int8_t defVal, std::function<bool(int8_t, int8_t, int8_t)> validator, int8_t min, int8_t max)
 {
   val = preferences.getChar(key, defVal);
   if(!validator(val, min, max)) {
@@ -77,7 +78,7 @@ CESP32_NVStorage::validatedLoad(const char* key, int8_t& val, int defVal, std::f
 }
 
 bool
-CESP32_NVStorage::validatedLoad(const char* key, uint16_t& val, int defVal, std::function<bool(uint16_t, uint16_t, uint16_t)> validator, int min, int max)
+CESP32_NVStorage::validatedLoad(const char* key, uint16_t& val, uint16_t defVal, std::function<bool(uint16_t, uint16_t, uint16_t)> validator, uint16_t min, uint16_t max)
 {
   val = preferences.getUShort(key, defVal);
   if(!validator(val, min, max)) {
@@ -134,6 +135,12 @@ bool u8inBounds(uint8_t test, uint8_t minLim, uint8_t maxLim)
   return INBOUNDS(test, minLim, maxLim);
 }
 
+bool u8inBoundsOrZero(uint8_t test, uint8_t minLim, uint8_t maxLim)
+{
+  return INBOUNDS(test, minLim, maxLim) || (test == 0);
+}
+
+
 bool s8inBounds(int8_t test, int8_t minLim, int8_t maxLim)
 {
   return INBOUNDS(test, minLim, maxLim);
diff --git a/src/Afterburner/src/Utility/NVCore.h b/src/Afterburner/src/Utility/NVCore.h
index 396cc69..46c1bd9 100644
--- a/src/Afterburner/src/Utility/NVCore.h
+++ b/src/Afterburner/src/Utility/NVCore.h
@@ -28,6 +28,7 @@
 
 bool finBounds(float tets, float min, float max);
 bool u8inBounds(uint8_t test, uint8_t minLim, uint8_t maxLim);
+bool u8inBoundsOrZero(uint8_t test, uint8_t minLim, uint8_t maxLim);
 bool s8inBounds(int8_t test, int8_t minLim, int8_t maxLim);
 bool u8Match2(uint8_t test, uint8_t test1, uint8_t test2);
 bool u16inBounds(uint16_t test, uint16_t minLim, uint16_t maxLim);
@@ -47,9 +48,9 @@ class CESP32_NVStorage {
 protected:
   Preferences preferences;
 protected:
-  bool validatedLoad(const char* key, int8_t& val, int defVal, std::function<bool(int8_t, int8_t, int8_t)> validator, int min, int max);
-  bool validatedLoad(const char* key, uint8_t& val, int defVal, std::function<bool(uint8_t, uint8_t, uint8_t)> validator, int min, int max, uint8_t mask=0xff);
-  bool validatedLoad(const char* key, uint16_t& val, int defVal, std::function<bool(uint16_t, uint16_t, uint16_t)> validator, int min, int max);
+  bool validatedLoad(const char* key, int8_t& val, int8_t defVal, std::function<bool(int8_t, int8_t, int8_t)> validator, int8_t min, int8_t max);
+  bool validatedLoad(const char* key, uint8_t& val, uint8_t defVal, std::function<bool(uint8_t, uint8_t, uint8_t)> validator, uint8_t min, uint8_t max, uint8_t mask=0xff);
+  bool validatedLoad(const char* key, uint16_t& val, uint16_t defVal, std::function<bool(uint16_t, uint16_t, uint16_t)> validator, uint16_t min, uint16_t max);
   bool validatedLoad(const char* key, long& val, long defVal, long min, long max);
   bool validatedLoad(const char* key, char* val, int maxlen, const char* defVal);
   bool validatedLoad(const char* key, float& val, float defVal, float min, float max);
diff --git a/src/Afterburner/src/Utility/NVStorage.cpp b/src/Afterburner/src/Utility/NVStorage.cpp
index c3f6925..85fb434 100644
--- a/src/Afterburner/src/Utility/NVStorage.cpp
+++ b/src/Afterburner/src/Utility/NVStorage.cpp
@@ -241,9 +241,9 @@ sHeaterTuning::load()
   validatedLoad("fanSensor", fanSensor, 1, u8inBounds, 1, 2);
   validatedLoad("glowDrive", glowDrive, 5, u8inBounds, 1, 6);
   if(sysVoltage == 120)
-    validatedLoad("lowVolts", lowVolts, 115, u8inBounds, 100, 125);
+    validatedLoad("lowVolts", lowVolts, 115, u8inBoundsOrZero, 100, 125);
   else
-    validatedLoad("lowVolts", lowVolts, 230, u8inBounds, 200, 250);
+    validatedLoad("lowVolts", lowVolts, 230, u8inBoundsOrZero, 200, 250);
   validatedLoad("pumpCal", pumpCal, 0.02, 0.001, 1);
   validatedLoad("tempOfs", tempOfs, 0.0, -10.0, +10.0);
   preferences.end();