diff --git a/lib/WebServerHandlers/UpgradeHandler.h b/lib/WebServerHandlers/UpgradeHandler.h
index 83fe3fd..f135b0e 100644
--- a/lib/WebServerHandlers/UpgradeHandler.h
+++ b/lib/WebServerHandlers/UpgradeHandler.h
@@ -174,7 +174,7 @@ public:
         Log.serrorln(
           FPSTR(L_PORTAL_OTA),
           F("File '%s', on writing %d bytes: %s"),
-          upload.filename.c_str(), upload.totalSize, result->error
+          upload.filename.c_str(), upload.totalSize, result->error.c_str()
         );
 
       } else {
diff --git a/src/MqttTask.h b/src/MqttTask.h
index 7236d0b..0b7f5d9 100644
--- a/src/MqttTask.h
+++ b/src/MqttTask.h
@@ -385,8 +385,8 @@ protected:
     bool isStupidMode = !settings.pid.enable && !settings.equitherm.enable;
     byte heatingMinTemp = isStupidMode ? settings.heating.minTemp : 10;
     byte heatingMaxTemp = isStupidMode ? settings.heating.maxTemp : 30;
-    bool editableOutdoorTemp = settings.sensors.outdoor.type == 1;
-    bool editableIndoorTemp = settings.sensors.indoor.type == 1;
+    bool editableOutdoorTemp = settings.sensors.outdoor.type == SensorType::MANUAL;
+    bool editableIndoorTemp = settings.sensors.indoor.type == SensorType::MANUAL;
 
     if (force || _dhwPresent != settings.opentherm.dhwPresent) {
       _dhwPresent = settings.opentherm.dhwPresent;
diff --git a/src/OpenThermTask.h b/src/OpenThermTask.h
index ac55146..f24a19e 100644
--- a/src/OpenThermTask.h
+++ b/src/OpenThermTask.h
@@ -257,7 +257,7 @@ protected:
       setMaxHeatingTemp(settings.heating.maxTemp);
 
       // Get outdoor temp (if necessary)
-      if (settings.sensors.outdoor.type == 0) {
+      if (settings.sensors.outdoor.type == SensorType::BOILER) {
         updateOutsideTemp();
       }
 
diff --git a/src/RegulatorTask.h b/src/RegulatorTask.h
index 150092d..df18016 100644
--- a/src/RegulatorTask.h
+++ b/src/RegulatorTask.h
@@ -84,7 +84,7 @@ protected:
     float newTemp = 0;
 
     // if use equitherm
-    if (settings.emergency.useEquitherm && settings.sensors.outdoor.type != 1) {
+    if (settings.emergency.useEquitherm && settings.sensors.outdoor.type != SensorType::MANUAL) {
       float etResult = getEquithermTemp(settings.heating.minTemp, settings.heating.maxTemp);
 
       if (fabs(prevEtResult - etResult) + 0.0001 >= 0.5) {
@@ -97,7 +97,7 @@ protected:
         newTemp += prevEtResult;
       }
 
-    } else if(settings.emergency.usePid && settings.sensors.indoor.type != 1) {
+    } else if(settings.emergency.usePid && settings.sensors.indoor.type != SensorType::MANUAL) {
       if (vars.parameters.heatingEnabled) {
         float pidResult = getPidTemp(
           settings.heating.minTemp,
diff --git a/src/SensorsTask.h b/src/SensorsTask.h
index ad6fca2..b0ea500 100644
--- a/src/SensorsTask.h
+++ b/src/SensorsTask.h
@@ -63,21 +63,21 @@ protected:
     bool indoorTempUpdated = false;
     bool outdoorTempUpdated = false;
 
-    if (settings.sensors.outdoor.type == 2 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
+    if (settings.sensors.outdoor.type == SensorType::DS18B20 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
       outdoorTemperatureSensor();
       outdoorTempUpdated = true;
     }
 
-    if (settings.sensors.indoor.type == 2 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
+    if (settings.sensors.indoor.type == SensorType::DS18B20 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
       indoorTemperatureSensor();
       indoorTempUpdated = true;
     }
-#if USE_BLE
-    else if (settings.sensors.indoor.type == 3) {
+    #if USE_BLE
+    else if (settings.sensors.indoor.type == SensorType::BLUETOOTH) {
       indoorTemperatureBluetoothSensor();
       indoorTempUpdated = true;
     }
-#endif
+    #endif
 
     if (outdoorTempUpdated && fabs(vars.temperatures.outdoor - this->filteredOutdoorTemp) > 0.099) {
       vars.temperatures.outdoor = this->filteredOutdoorTemp + settings.sensors.outdoor.offset;
diff --git a/src/Settings.h b/src/Settings.h
index da988fe..6576040 100644
--- a/src/Settings.h
+++ b/src/Settings.h
@@ -100,15 +100,13 @@ struct Settings {
 
   struct {
     struct {
-      // 0 - boiler, 1 - manual, 2 - ds18b20
-      byte type = 0;
+      SensorType type = SensorType::BOILER;
       byte gpio = DEFAULT_SENSOR_OUTDOOR_GPIO;
       float offset = 0.0f;
     } outdoor;
 
     struct {
-      // 1 - manual, 2 - ds18b20, 3 - ble
-      byte type = 1;
+      SensorType type = SensorType::MANUAL;
       byte gpio = DEFAULT_SENSOR_INDOOR_GPIO;
       uint8_t bleAddresss[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
       float offset = 0.0f;
diff --git a/src/defines.h b/src/defines.h
index dc15054..852ae42 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -111,4 +111,11 @@
 
 #define GPIO_IS_VALID(gpioNum) (gpioNum != GPIO_IS_NOT_CONFIGURED && GPIO_IS_VALID_GPIO(gpioNum))
 
+enum class SensorType : byte {
+  BOILER,
+  MANUAL,
+  DS18B20,
+  BLUETOOTH
+};
+
 char buffer[255];
\ No newline at end of file
diff --git a/src/utils.h b/src/utils.h
index fac36e0..c17c6ed 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -323,11 +323,11 @@ void settingsToJson(const Settings& src, JsonVariant dst, bool safe = false) {
   dst["equitherm"]["k_factor"] = roundd(src.equitherm.k_factor, 3);
   dst["equitherm"]["t_factor"] = roundd(src.equitherm.t_factor, 3);
 
-  dst["sensors"]["outdoor"]["type"] = src.sensors.outdoor.type;
+  dst["sensors"]["outdoor"]["type"] = static_cast<byte>(src.sensors.outdoor.type);
   dst["sensors"]["outdoor"]["gpio"] = src.sensors.outdoor.gpio;
   dst["sensors"]["outdoor"]["offset"] = roundd(src.sensors.outdoor.offset, 2);
 
-  dst["sensors"]["indoor"]["type"] = src.sensors.indoor.type;
+  dst["sensors"]["indoor"]["type"] = static_cast<byte>(src.sensors.indoor.type);
   dst["sensors"]["indoor"]["gpio"] = src.sensors.indoor.gpio;
 
   char bleAddress[18];
@@ -574,7 +574,7 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
   }
 
   if (src["emergency"]["useEquitherm"].is<bool>()) {
-    if (dst.sensors.outdoor.type != 1) {
+    if (dst.sensors.outdoor.type != SensorType::MANUAL) {
       dst.emergency.useEquitherm = src["emergency"]["useEquitherm"].as<bool>();
 
     } else {
@@ -589,7 +589,7 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
   }
 
   if (src["emergency"]["usePid"].is<bool>()) {
-    if (dst.sensors.indoor.type != 1) {
+    if (dst.sensors.indoor.type != SensorType::MANUAL) {
       dst.emergency.usePid = src["emergency"]["usePid"].as<bool>();
 
     } else {
@@ -792,16 +792,27 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
 
   // sensors
   if (!src["sensors"]["outdoor"]["type"].isNull()) {
-    unsigned char value = src["sensors"]["outdoor"]["type"].as<unsigned char>();
+    byte value = src["sensors"]["outdoor"]["type"].as<unsigned char>();
 
-    if (value >= 0 && value <= 2) {
-      dst.sensors.outdoor.type = value;
+    switch (value) {
+      case static_cast<byte>(SensorType::BOILER):
+        dst.sensors.outdoor.type = SensorType::BOILER;
+        changed = true;
+        break;
 
-      if (dst.sensors.outdoor.type == 1) {
+      case static_cast<byte>(SensorType::MANUAL):
+        dst.sensors.outdoor.type = SensorType::MANUAL;
         dst.emergency.useEquitherm = false;
-      }
+        changed = true;
+        break;
 
-      changed = true;
+      case static_cast<byte>(SensorType::DS18B20):
+        dst.sensors.outdoor.type = SensorType::DS18B20;
+        changed = true;
+        break;
+
+      default:
+        break;
     }
   }
 
@@ -832,16 +843,35 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
   }
 
   if (!src["sensors"]["indoor"]["type"].isNull()) {
-    unsigned char value = src["sensors"]["indoor"]["type"].as<unsigned char>();
+    byte value = src["sensors"]["indoor"]["type"].as<unsigned char>();
 
-    if (value >= 1 && value <= 3) {
-      dst.sensors.indoor.type = value;
 
-      if (dst.sensors.indoor.type == 1) {
-        dst.emergency.usePid = false;
-      }
+    switch (value) {
+      case static_cast<byte>(SensorType::BOILER):
+        dst.sensors.indoor.type = SensorType::BOILER;
+        changed = true;
+        break;
 
-      changed = true;
+      case static_cast<byte>(SensorType::MANUAL):
+        dst.sensors.indoor.type = SensorType::MANUAL;
+        dst.emergency.useEquitherm = false;
+        changed = true;
+        break;
+
+      case static_cast<byte>(SensorType::DS18B20):
+        dst.sensors.indoor.type = SensorType::DS18B20;
+        changed = true;
+        break;
+
+      #if USE_BLE
+      case static_cast<byte>(SensorType::BLUETOOTH):
+        dst.sensors.indoor.type = SensorType::BLUETOOTH;
+        changed = true;
+        break;
+      #endif
+
+      default:
+        break;
     }
   }
 
@@ -1001,7 +1031,7 @@ bool jsonToVars(const JsonVariantConst src, Variables& dst) {
   if (!src["temperatures"]["indoor"].isNull()) {
     double value = src["temperatures"]["indoor"].as<double>();
 
-    if (settings.sensors.indoor.type == 1 && value > -100 && value < 100) {
+    if (settings.sensors.indoor.type == SensorType::MANUAL && value > -100 && value < 100) {
       dst.temperatures.indoor = roundd(value, 2);
       changed = true;
     }
@@ -1010,7 +1040,7 @@ bool jsonToVars(const JsonVariantConst src, Variables& dst) {
   if (!src["temperatures"]["outdoor"].isNull()) {
     double value = src["temperatures"]["outdoor"].as<double>();
 
-    if (settings.sensors.outdoor.type == 1 && value > -100 && value < 100) {
+    if (settings.sensors.outdoor.type == SensorType::MANUAL && value > -100 && value < 100) {
       dst.temperatures.outdoor = roundd(value, 2);
       changed = true;
     }