diff --git a/data/settings.html b/data/settings.html
index d29695c..ddcdf82 100644
--- a/data/settings.html
+++ b/data/settings.html
@@ -63,13 +63,13 @@
         <div id="opentherm-settings-busy" aria-busy="true"></div>
         <form action="/api/settings" id="opentherm-settings" class="hidden">
           <div class="grid">
-            <label for="opentherm-in-pin">
+            <label for="opentherm-in-gpio">
               In GPIO
-              <input type="number" inputmode="numeric" class="opentherm-in-pin" name="opentherm[inPin]" min="0" max="99" step="1" required>
+              <input type="number" inputmode="numeric" class="opentherm-in-gpio" name="opentherm[inGpio]" min="0" max="254" step="1">
             </label>
-            <label for="opentherm-in-pin">
+            <label for="opentherm-in-gpio">
               Out GPIO
-              <input type="number" inputmode="numeric" class="opentherm-out-pin" name="opentherm[outPin]" min="0" max="99" step="1" required>
+              <input type="number" inputmode="numeric" class="opentherm-out-gpio" name="opentherm[outGpio]" min="0" max="254" step="1">
             </label>
             <label for="opentherm-member-id-code">
               Master MemberID code
@@ -77,10 +77,6 @@
             </label>
           </div>
 
-          <fieldset>
-            <mark>After changing GPIO, the ESP must be restarted for the changes to take effect.</mark>
-          </fieldset>
-
           <fieldset>
             <legend>Options</legend>
             <label for="opentherm-dhw-present">
@@ -190,9 +186,9 @@
             </label>
           </fieldset>
 
-          <label for="outdoor-sensor-pin">
+          <label for="outdoor-sensor-gpio">
             GPIO
-            <input type="number" inputmode="numeric" class="outdoor-sensor-pin" name="sensors[outdoor][pin]" min="0" max="99" step="1" required>
+            <input type="number" inputmode="numeric" class="outdoor-sensor-gpio" name="sensors[outdoor][gpio]" min="0" max="254" step="1">
           </label>
           <label for="outdoor-sensor-offset">
             Temp offset (calibration)
@@ -229,9 +225,9 @@
             </label>
           </fieldset>
 
-          <label for="indoor-sensor-pin">
+          <label for="indoor-sensor-gpio">
             GPIO
-            <input type="number" inputmode="numeric" class="indoor-sensor-pin" name="sensors[indoor][pin]" min="0" max="99" step="1" required>
+            <input type="number" inputmode="numeric" class="indoor-sensor-gpio" name="sensors[indoor][gpio]" min="0" max="254" step="1">
           </label>
 
           <div class="grid">
@@ -267,9 +263,9 @@
           <br>
 
           <div class="grid">
-            <label for="extpump-pin">
+            <label for="extpump-gpio">
               Relay GPIO
-              <input type="number" inputmode="numeric" class="extpump-pin" name="externalPump[pin]" min="0" max="99" step="1" required>
+              <input type="number" inputmode="numeric" class="extpump-gpio" name="externalPump[gpio]" min="0" max="254" step="1">
             </label>
             <label for="extpump-pc-time">
               Post circulation time <small>(min)</small>
diff --git a/data/static/app.js.gz b/data/static/app.js.gz
index 4bc122e..306d6ea 100644
Binary files a/data/static/app.js.gz and b/data/static/app.js.gz differ
diff --git a/lib/CustomOpenTherm/CustomOpenTherm.h b/lib/CustomOpenTherm/CustomOpenTherm.h
index 6dc7f40..e8aa77d 100644
--- a/lib/CustomOpenTherm/CustomOpenTherm.h
+++ b/lib/CustomOpenTherm/CustomOpenTherm.h
@@ -8,6 +8,7 @@ public:
   typedef std::function<void(unsigned long, unsigned long, OpenThermResponseStatus, byte)> AfterSendRequestCallback;
 
   CustomOpenTherm(int inPin = 4, int outPin = 5, bool isSlave = false) : OpenTherm(inPin, outPin, isSlave) {}
+  ~CustomOpenTherm() {}
 
   CustomOpenTherm* setYieldCallback(YieldCallback callback = nullptr) {
     this->yieldCallback = callback;
diff --git a/platformio.ini b/platformio.ini
index 4fa665a..136261b 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -17,7 +17,7 @@ framework = arduino
 lib_deps = 
 	bblanchon/ArduinoJson@^7.0.3
 	;ihormelnyk/OpenTherm Library@^1.1.5
-	https://github.com/ihormelnyk/opentherm_library.git?080324
+	https://github.com/ihormelnyk/opentherm_library.git
 	arduino-libraries/ArduinoMqttClient@^0.1.8
 	lennarthennigs/ESP Telnet@^2.2
 	gyverlibs/FileData@^1.0.2
@@ -34,18 +34,18 @@ build_flags =
 	-D USE_SERIAL=${secrets.use_serial}
 	-D USE_TELNET=${secrets.use_telnet}
 	-D DEBUG_BY_DEFAULT=${secrets.debug}
-	-D HOSTNAME_DEFAULT='"${secrets.hostname}"'
-	-D AP_SSID_DEFAULT='"${secrets.ap_ssid}"'
-	-D AP_PASSWORD_DEFAULT='"${secrets.ap_password}"'
-	-D STA_SSID_DEFAULT='"${secrets.sta_ssid}"'
-	-D STA_PASSWORD_DEFAULT='"${secrets.sta_password}"'
-	-D PORTAL_LOGIN_DEFAULT='"${secrets.portal_login}"'
-	-D PORTAL_PASSWORD_DEFAULT='"${secrets.portal_password}"'
-	-D MQTT_SERVER_DEFAULT='"${secrets.mqtt_server}"'
-	-D MQTT_PORT_DEFAULT=${secrets.mqtt_port}
-	-D MQTT_USER_DEFAULT='"${secrets.mqtt_user}"'
-	-D MQTT_PASSWORD_DEFAULT='"${secrets.mqtt_password}"'
-	-D MQTT_PREFIX_DEFAULT='"${secrets.mqtt_prefix}"'
+	-D DEFAULT_HOSTNAME='"${secrets.hostname}"'
+	-D DEFAULT_AP_SSID='"${secrets.ap_ssid}"'
+	-D DEFAULT_AP_PASSWORD='"${secrets.ap_password}"'
+	-D DEFAULT_STA_SSID='"${secrets.sta_ssid}"'
+	-D DEFAULT_STA_PASSWORD='"${secrets.sta_password}"'
+	-D DEFAULT_PORTAL_LOGIN='"${secrets.portal_login}"'
+	-D DEFAULT_PORTAL_PASSWORD='"${secrets.portal_password}"'
+	-D DEFAULT_MQTT_SERVER='"${secrets.mqtt_server}"'
+	-D DEFAULT_MQTT_PORT=${secrets.mqtt_port}
+	-D DEFAULT_MQTT_USER='"${secrets.mqtt_user}"'
+	-D DEFAULT_MQTT_PASSWORD='"${secrets.mqtt_password}"'
+	-D DEFAULT_MQTT_PREFIX='"${secrets.mqtt_prefix}"'
 upload_speed = 921600
 monitor_speed = 115200
 monitor_filters = direct
@@ -67,7 +67,7 @@ board_build.ldscript = eagle.flash.1m256.ld
 ;board_build.ldscript = eagle.flash.4m1m.ld
 
 [esp32_defaults]
-platform = espressif32
+platform = espressif32@^6.5
 board_build.partitions = esp32_partitions.csv
 lib_deps =
 	${env.lib_deps}
@@ -91,12 +91,12 @@ extra_scripts = ${esp8266_defaults.extra_scripts}
 board_build.ldscript = ${esp8266_defaults.board_build.ldscript}
 build_flags = 
 	${esp8266_defaults.build_flags}
-	-D OT_IN_PIN_DEFAULT=4
-	-D OT_OUT_PIN_DEFAULT=5
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=12
-	-D SENSOR_INDOOR_PIN_DEFAULT=14
-	-D LED_STATUS_PIN=13
-	-D LED_OT_RX_PIN=15
+	-D DEFAULT_OT_IN_GPIO=4
+	-D DEFAULT_OT_OUT_GPIO=5
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=12
+	-D DEFAULT_SENSOR_INDOOR_GPIO=14
+	-D LED_STATUS_GPIO=13
+	-D LED_OT_RX_GPIO=15
 
 [env:d1_mini_lite]
 platform = ${esp8266_defaults.platform}
@@ -107,12 +107,12 @@ extra_scripts = ${esp8266_defaults.extra_scripts}
 board_build.ldscript = ${esp8266_defaults.board_build.ldscript}
 build_flags = 
 	${esp8266_defaults.build_flags}
-	-D OT_IN_PIN_DEFAULT=4
-	-D OT_OUT_PIN_DEFAULT=5
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=12
-	-D SENSOR_INDOOR_PIN_DEFAULT=14
-	-D LED_STATUS_PIN=13
-	-D LED_OT_RX_PIN=15
+	-D DEFAULT_OT_IN_GPIO=4
+	-D DEFAULT_OT_OUT_GPIO=5
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=12
+	-D DEFAULT_SENSOR_INDOOR_GPIO=14
+	-D LED_STATUS_GPIO=13
+	-D LED_OT_RX_GPIO=15
 
 [env:d1_mini_pro]
 platform = ${esp8266_defaults.platform}
@@ -123,12 +123,12 @@ extra_scripts = ${esp8266_defaults.extra_scripts}
 board_build.ldscript = ${esp8266_defaults.board_build.ldscript}
 build_flags = 
 	${esp8266_defaults.build_flags}
-	-D OT_IN_PIN_DEFAULT=4
-	-D OT_OUT_PIN_DEFAULT=5
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=12
-	-D SENSOR_INDOOR_PIN_DEFAULT=14
-	-D LED_STATUS_PIN=13
-	-D LED_OT_RX_PIN=15
+	-D DEFAULT_OT_IN_GPIO=4
+	-D DEFAULT_OT_OUT_GPIO=5
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=12
+	-D DEFAULT_SENSOR_INDOOR_GPIO=14
+	-D LED_STATUS_GPIO=13
+	-D LED_OT_RX_GPIO=15
 
 [env:s2_mini]
 platform = ${esp32_defaults.platform}
@@ -139,12 +139,12 @@ lib_ignore = ${esp32_defaults.lib_ignore}
 extra_scripts = ${esp32_defaults.extra_scripts}
 build_flags = 
 	${esp32_defaults.build_flags}
-	-D OT_IN_PIN_DEFAULT=33
-	-D OT_OUT_PIN_DEFAULT=35
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=9
-	-D SENSOR_INDOOR_PIN_DEFAULT=7
-	-D LED_STATUS_PIN=11
-	-D LED_OT_RX_PIN=12
+	-D DEFAULT_OT_IN_GPIO=33
+	-D DEFAULT_OT_OUT_GPIO=35
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=9
+	-D DEFAULT_SENSOR_INDOOR_GPIO=7
+	-D LED_STATUS_GPIO=11
+	-D LED_OT_RX_GPIO=12
 
 [env:s3_mini] 
 platform = ${esp32_defaults.platform}
@@ -158,12 +158,12 @@ extra_scripts = ${esp32_defaults.extra_scripts}
 build_flags = 
 	${esp32_defaults.build_flags}
 	-D USE_BLE=1
-	-D OT_IN_PIN_DEFAULT=35
-	-D OT_OUT_PIN_DEFAULT=36
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=13
-	-D SENSOR_INDOOR_PIN_DEFAULT=12
-	-D LED_STATUS_PIN=11
-	-D LED_OT_RX_PIN=10
+	-D DEFAULT_OT_IN_GPIO=35
+	-D DEFAULT_OT_OUT_GPIO=36
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=13
+	-D DEFAULT_SENSOR_INDOOR_GPIO=12
+	-D LED_STATUS_GPIO=11
+	-D LED_OT_RX_GPIO=10
 
 [env:c3_mini] 
 platform = ${esp32_defaults.platform}
@@ -179,12 +179,12 @@ build_unflags =
 build_flags = 
 	${esp32_defaults.build_flags}
 	-D USE_BLE=1
-	-D OT_IN_PIN_DEFAULT=8
-	-D OT_OUT_PIN_DEFAULT=10
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=0
-	-D SENSOR_INDOOR_PIN_DEFAULT=1
-	-D LED_STATUS_PIN=4
-	-D LED_OT_RX_PIN=5
+	-D DEFAULT_OT_IN_GPIO=8
+	-D DEFAULT_OT_OUT_GPIO=10
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=0
+	-D DEFAULT_SENSOR_INDOOR_GPIO=1
+	-D LED_STATUS_GPIO=4
+	-D LED_OT_RX_GPIO=5
 
 [env:nodemcu_32s]
 platform = ${esp32_defaults.platform}
@@ -198,12 +198,12 @@ extra_scripts = ${esp32_defaults.extra_scripts}
 build_flags = 
 	${esp32_defaults.build_flags}
 	-D USE_BLE=1
-	-D OT_IN_PIN_DEFAULT=21
-	-D OT_OUT_PIN_DEFAULT=22
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=12
-	-D SENSOR_INDOOR_PIN_DEFAULT=13
-	-D LED_STATUS_PIN=2 ; 18
-	-D LED_OT_RX_PIN=19
+	-D DEFAULT_OT_IN_GPIO=21
+	-D DEFAULT_OT_OUT_GPIO=22
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=12
+	-D DEFAULT_SENSOR_INDOOR_GPIO=13
+	-D LED_STATUS_GPIO=2 ; 18
+	-D LED_OT_RX_GPIO=19
 	;-D WOKWI=1
 
 [env:d1_mini32]
@@ -218,9 +218,9 @@ extra_scripts = ${esp32_defaults.extra_scripts}
 build_flags = 
 	${esp32_defaults.build_flags}
 	-D USE_BLE=1
-	-D OT_IN_PIN_DEFAULT=21
-	-D OT_OUT_PIN_DEFAULT=22
-	-D SENSOR_OUTDOOR_PIN_DEFAULT=12
-	-D SENSOR_INDOOR_PIN_DEFAULT=18
-	-D LED_STATUS_PIN=2
-	-D LED_OT_RX_PIN=19
+	-D DEFAULT_OT_IN_GPIO=21
+	-D DEFAULT_OT_OUT_GPIO=22
+	-D DEFAULT_SENSOR_OUTDOOR_GPIO=12
+	-D DEFAULT_SENSOR_INDOOR_GPIO=18
+	-D LED_STATUS_GPIO=2
+	-D LED_OT_RX_GPIO=19
diff --git a/src/MainTask.h b/src/MainTask.h
index b0866f1..62519a0 100644
--- a/src/MainTask.h
+++ b/src/MainTask.h
@@ -52,14 +52,14 @@ protected:
   }
 
   void setup() {
-    #ifdef LED_STATUS_PIN
-      pinMode(LED_STATUS_PIN, OUTPUT);
-      digitalWrite(LED_STATUS_PIN, LOW);
+    #ifdef LED_STATUS_GPIO
+      pinMode(LED_STATUS_GPIO, OUTPUT);
+      digitalWrite(LED_STATUS_GPIO, LOW);
     #endif
 
-    if (settings.externalPump.pin != 0) {
-      pinMode(settings.externalPump.pin, OUTPUT);
-      digitalWrite(settings.externalPump.pin, LOW);
+    if (GPIO_IS_VALID(settings.externalPump.gpio)) {
+      pinMode(settings.externalPump.gpio, OUTPUT);
+      digitalWrite(settings.externalPump.gpio, LOW);
     }
   }
 
@@ -89,10 +89,6 @@ protected:
       Log.sinfoln(FPSTR(L_MAIN), F("Restart signal received. Restart after 10 sec."));
     }
 
-    if (!tOt->isEnabled() && settings.opentherm.inPin > 0 && settings.opentherm.outPin > 0 && settings.opentherm.inPin != settings.opentherm.outPin) {
-      tOt->enable();
-    }
-
     if (network->isConnected()) {
       vars.sensors.rssi = WiFi.RSSI();
 
@@ -140,8 +136,8 @@ protected:
     this->yield();
 
 
-    #ifdef LED_STATUS_PIN
-      this->ledStatus(LED_STATUS_PIN);
+    #ifdef LED_STATUS_GPIO
+      this->ledStatus(LED_STATUS_GPIO);
     #endif
     this->externalPump();
     this->yield();
@@ -211,7 +207,7 @@ protected:
     }
   }
 
-  void ledStatus(uint8_t ledPin) {
+  void ledStatus(uint8_t gpio) {
     uint8_t errors[4];
     uint8_t errCount = 0;
     static uint8_t errPos = 0;
@@ -219,7 +215,7 @@ protected:
     static bool ledOn = false;
 
     if (!this->blinkerInitialized) {
-      this->blinker->init(ledPin);
+      this->blinker->init(gpio);
       this->blinkerInitialized = true;
     }
 
@@ -247,14 +243,14 @@ protected:
     if (!this->blinker->running() && millis() - endBlinkTime >= 5000) {
       if (errCount == 0) {
         if (!ledOn) {
-          digitalWrite(ledPin, HIGH);
+          digitalWrite(gpio, HIGH);
           ledOn = true;
         }
 
         return;
 
       } else if (ledOn) {
-        digitalWrite(ledPin, LOW);
+        digitalWrite(gpio, LOW);
         ledOn = false;
         endBlinkTime = millis();
         return;
@@ -283,10 +279,10 @@ protected:
       this->heatingEnabled = true;
     }
     
-    if (!settings.externalPump.use || settings.externalPump.pin == 0) {
+    if (!settings.externalPump.use || !GPIO_IS_VALID(settings.externalPump.gpio)) {
       if (vars.states.externalPump) {
-        if (settings.externalPump.pin != 0) {
-          digitalWrite(settings.externalPump.pin, LOW);
+        if (GPIO_IS_VALID(settings.externalPump.gpio)) {
+          digitalWrite(settings.externalPump.gpio, LOW);
         }
 
         vars.states.externalPump = false;
@@ -300,7 +296,7 @@ protected:
 
     if (vars.states.externalPump && !this->heatingEnabled) {
       if (this->extPumpStartReason == MainTask::PumpStartReason::HEATING && millis() - this->heatingDisabledTime > (settings.externalPump.postCirculationTime * 1000u)) {
-        digitalWrite(settings.externalPump.pin, LOW);
+        digitalWrite(settings.externalPump.gpio, LOW);
 
         vars.states.externalPump = false;
         vars.parameters.extPumpLastEnableTime = millis();
@@ -308,7 +304,7 @@ protected:
         Log.sinfoln("EXTPUMP", F("Disabled: expired post circulation time"));
 
       } else if (this->extPumpStartReason == MainTask::PumpStartReason::ANTISTUCK && millis() - this->externalPumpStartTime >= (settings.externalPump.antiStuckTime * 1000u)) {
-        digitalWrite(settings.externalPump.pin, LOW);
+        digitalWrite(settings.externalPump.gpio, LOW);
 
         vars.states.externalPump = false;
         vars.parameters.extPumpLastEnableTime = millis();
@@ -324,7 +320,7 @@ protected:
       this->externalPumpStartTime = millis();
       this->extPumpStartReason = MainTask::PumpStartReason::HEATING;
 
-      digitalWrite(settings.externalPump.pin, HIGH);
+      digitalWrite(settings.externalPump.gpio, HIGH);
 
       Log.sinfoln("EXTPUMP", F("Enabled: heating on"));
 
@@ -333,7 +329,7 @@ protected:
       this->externalPumpStartTime = millis();
       this->extPumpStartReason = MainTask::PumpStartReason::ANTISTUCK;
 
-      digitalWrite(settings.externalPump.pin, HIGH);
+      digitalWrite(settings.externalPump.gpio, HIGH);
 
       Log.sinfoln("EXTPUMP", F("Enabled: anti stuck"));
     }
diff --git a/src/OpenThermTask.h b/src/OpenThermTask.h
index ff53ed6..ac55146 100644
--- a/src/OpenThermTask.h
+++ b/src/OpenThermTask.h
@@ -1,27 +1,35 @@
 #include <CustomOpenTherm.h>
-
-CustomOpenTherm* ot;
 extern FileData fsSettings;
 
 class OpenThermTask : public Task {
 public:
-  OpenThermTask(bool _enabled = false, unsigned long _interval = 0) : Task(_enabled, _interval) {
-    ot = new CustomOpenTherm(settings.opentherm.inPin, settings.opentherm.outPin);
+  OpenThermTask(bool _enabled = false, unsigned long _interval = 0) : Task(_enabled, _interval) {}
+
+  ~OpenThermTask() {
+    delete this->instance;
   }
 
 protected:
-  unsigned short readyTime = 60000;
-  unsigned short dhwSetTempInterval = 60000;
-  unsigned short heatingSetTempInterval = 60000;
+  const unsigned short readyTime = 60000;
+  const unsigned short dhwSetTempInterval = 60000;
+  const unsigned short heatingSetTempInterval = 60000;
+  const unsigned int initializingInterval = 3600000;
 
+  CustomOpenTherm* instance = nullptr;
+  unsigned long instanceCreatedTime = 0;
+  byte instanceInGpio = 0;
+  byte instanceOutGpio = 0;
+  bool isInitialized = false;
+  unsigned long initializedTime = 0;
+  unsigned int initializedMemberIdCode = 0;
+  byte dhwFlowRateMultiplier = 1;
+  byte pressureMultiplier = 1;
   bool pump = true;
   unsigned long lastSuccessResponse = 0;
   unsigned long prevUpdateNonEssentialVars = 0;
-  unsigned long startupTime = millis();
   unsigned long dhwSetTempTime = 0;
   unsigned long heatingSetTempTime = 0;
-  byte dhwFlowRateMultiplier = 1;
-  byte pressureMultiplier = 1;
+
 
   const char* getTaskName() {
     return "OpenTherm";
@@ -36,9 +44,35 @@ protected:
   }
 
   void setup() {
-    Log.sinfoln(FPSTR(L_OT), F("Started. GPIO IN: %hhu, GPIO OUT: %hhu"), settings.opentherm.inPin, settings.opentherm.outPin);
+    #ifdef LED_OT_RX_GPIO
+      pinMode(LED_OT_RX_GPIO, OUTPUT);
+      digitalWrite(LED_OT_RX_GPIO, LOW);
+    #endif
 
-    ot->setAfterSendRequestCallback([this](unsigned long request, unsigned long response, OpenThermResponseStatus status, byte attempt) {
+    // delete instance
+    if (this->instance != nullptr) {
+      delete this->instance;
+      this->instance = nullptr;
+      Log.sinfoln(FPSTR(L_OT), F("Stopped"));
+    }
+
+    if (!GPIO_IS_VALID(settings.opentherm.inGpio) || !GPIO_IS_VALID(settings.opentherm.outGpio)) {
+      Log.swarningln(FPSTR(L_OT), F("Not started. GPIO IN: %hhu or GPIO OUT: %hhu is not valid"), settings.opentherm.inGpio, settings.opentherm.outGpio);
+      return;
+    }
+
+    // create instance
+    this->instance = new CustomOpenTherm(settings.opentherm.inGpio, settings.opentherm.outGpio);
+
+    // flags
+    this->instanceCreatedTime = millis();
+    this->instanceInGpio = settings.opentherm.inGpio;
+    this->instanceOutGpio = settings.opentherm.outGpio;
+    this->isInitialized = false;
+
+    Log.sinfoln(FPSTR(L_OT), F("Started. GPIO IN: %hhu, GPIO OUT: %hhu"), settings.opentherm.inGpio, settings.opentherm.outGpio);
+
+    this->instance->setAfterSendRequestCallback([this](unsigned long request, unsigned long response, OpenThermResponseStatus status, byte attempt) {
       Log.straceln(
         FPSTR(L_OT),
         F("ID: %4d   Request: %8lx   Response: %8lx   Attempt: %2d   Status: %s"),
@@ -48,68 +82,39 @@ protected:
       if (status == OpenThermResponseStatus::SUCCESS) {
         this->lastSuccessResponse = millis();
 
-        #ifdef LED_OT_RX_PIN
+        #ifdef LED_OT_RX_GPIO
         {
-          digitalWrite(LED_OT_RX_PIN, HIGH);
+          digitalWrite(LED_OT_RX_GPIO, HIGH);
           delayMicroseconds(2000);
-          digitalWrite(LED_OT_RX_PIN, LOW);
+          digitalWrite(LED_OT_RX_GPIO, LOW);
         }
         #endif
       }
     });
 
-    ot->setYieldCallback([this]() {
+    this->instance->setYieldCallback([this]() {
       this->delay(25);
     });
 
-    ot->begin();
-
-    #ifdef LED_OT_RX_PIN
-      pinMode(LED_OT_RX_PIN, OUTPUT);
-      digitalWrite(LED_OT_RX_PIN, LOW);
-    #endif
-  }
-
-  void initBoiler() {
-    this->dhwFlowRateMultiplier = 1;
-    this->pressureMultiplier = 1;
-
-    // Not all boilers support these, only try once when the boiler becomes connected
-    if (updateSlaveVersion()) {
-      Log.straceln(FPSTR(L_OT), F("Slave version: %u, type: %u"), vars.parameters.slaveVersion, vars.parameters.slaveType);
-
-    } else {
-      Log.swarningln(FPSTR(L_OT), F("Get slave version failed"));
-    }
-
-    // 0x013F
-    if (setMasterVersion(0x3F, 0x01)) {
-      Log.straceln(FPSTR(L_OT), F("Master version: %u, type: %u"), vars.parameters.masterVersion, vars.parameters.masterType);
-      
-    } else {
-      Log.swarningln(FPSTR(L_OT), F("Set master version failed"));
-    }
-
-    if (updateSlaveConfig()) {
-      Log.straceln(FPSTR(L_OT), F("Slave member id: %u, flags: %u"), vars.parameters.slaveMemberId, vars.parameters.slaveFlags);
-
-    } else {
-      Log.swarningln(FPSTR(L_OT), F("Get slave config failed"));
-    }
-
-    if (setMasterConfig(settings.opentherm.memberIdCode & 0xFF, (settings.opentherm.memberIdCode & 0xFFFF) >> 8)) {
-      Log.straceln(FPSTR(L_OT), F("Master member id: %u, flags: %u"), vars.parameters.masterMemberId, vars.parameters.masterFlags);
-      
-    } else {
-      Log.swarningln(FPSTR(L_OT), F("Set master config failed"));
-    }
+    this->instance->begin();
   }
 
   void loop() {
     static byte currentHeatingTemp, currentDhwTemp = 0;
-    unsigned long localResponse;
 
-    bool heatingEnabled = (vars.states.emergency || settings.heating.enable) && this->pump && isReady();
+    if (this->instanceInGpio != settings.opentherm.inGpio || this->instanceOutGpio != settings.opentherm.outGpio) {
+      this->setup();
+
+    } else if (this->initializedMemberIdCode != settings.opentherm.memberIdCode || millis() - this->initializedTime > this->initializingInterval) {
+      this->isInitialized = false; 
+    }
+
+    if (this->instance == nullptr) {
+      this->delay(5000);
+      return;
+    }
+
+    bool heatingEnabled = (vars.states.emergency || settings.heating.enable) && this->pump && this->isReady();
     bool heatingCh2Enabled = settings.opentherm.heatingCh2Enabled;
     if (settings.opentherm.heatingCh1ToCh2) {
       heatingCh2Enabled = heatingEnabled;
@@ -118,7 +123,7 @@ protected:
       heatingCh2Enabled = settings.opentherm.dhwPresent && settings.dhw.enable;
     }
 
-    localResponse = ot->setBoilerStatus(
+    unsigned long response = this->instance->setBoilerStatus(
       heatingEnabled,
       settings.opentherm.dhwPresent && settings.dhw.enable,
       false,
@@ -128,20 +133,20 @@ protected:
       settings.opentherm.dhwBlocking
     );
 
-    if (!CustomOpenTherm::isValidResponse(localResponse)) {
-      Log.swarningln(FPSTR(L_OT), F("Invalid response after setBoilerStatus: %s"), CustomOpenTherm::statusToString(ot->getLastResponseStatus()));
+    if (!CustomOpenTherm::isValidResponse(response)) {
+      Log.swarningln(FPSTR(L_OT), F("Invalid response after setBoilerStatus: %s"), CustomOpenTherm::statusToString(this->instance->getLastResponseStatus()));
     }
 
     if (!vars.states.otStatus && millis() - this->lastSuccessResponse < 1150) {
-      Log.sinfoln(FPSTR(L_OT), F("Connected. Initializing"));
+      Log.sinfoln(FPSTR(L_OT), F("Connected"));
       
       vars.states.otStatus = true;
-      this->initBoiler();
       
     } else if (vars.states.otStatus && millis() - this->lastSuccessResponse > 1150) {
       Log.swarningln(FPSTR(L_OT), F("Disconnected"));
 
       vars.states.otStatus = false;
+      this->isInitialized = false;
     }
 
     // If boiler is disconnected, no need try setting other OT stuff
@@ -155,17 +160,27 @@ protected:
       return;
     }
 
+    if (!this->isInitialized) {
+      Log.sinfoln(FPSTR(L_OT), F("Initializing..."));
+      this->isInitialized = true;
+      this->initializedTime = millis();
+      this->initializedMemberIdCode = settings.opentherm.memberIdCode;
+      this->dhwFlowRateMultiplier = 1;
+      this->pressureMultiplier = 1;
+      this->initialize();
+    }
+
     if (vars.parameters.heatingEnabled != heatingEnabled) {
       this->prevUpdateNonEssentialVars = 0;
       vars.parameters.heatingEnabled = heatingEnabled;
       Log.sinfoln(FPSTR(L_OT_HEATING), "%s", heatingEnabled ? F("Enabled") : F("Disabled"));
     }
 
-    vars.states.heating = CustomOpenTherm::isCentralHeatingActive(localResponse);
-    vars.states.dhw = settings.opentherm.dhwPresent ? CustomOpenTherm::isHotWaterActive(localResponse) : false;
-    vars.states.flame = CustomOpenTherm::isFlameOn(localResponse);
-    vars.states.fault = CustomOpenTherm::isFault(localResponse);
-    vars.states.diagnostic = CustomOpenTherm::isDiagnostic(localResponse);
+    vars.states.heating = CustomOpenTherm::isCentralHeatingActive(response);
+    vars.states.dhw = settings.opentherm.dhwPresent ? CustomOpenTherm::isHotWaterActive(response) : false;
+    vars.states.flame = CustomOpenTherm::isFlameOn(response);
+    vars.states.fault = CustomOpenTherm::isFault(response);
+    vars.states.diagnostic = CustomOpenTherm::isDiagnostic(response);
 
     // These parameters will be updated every minute
     if (millis() - this->prevUpdateNonEssentialVars > 60000) {
@@ -282,7 +297,7 @@ protected:
     // Fault reset action
     if (vars.actions.resetFault) {
       if (vars.states.fault) {
-        if (ot->sendBoilerReset()) {
+        if (this->instance->sendBoilerReset()) {
           Log.sinfoln(FPSTR(L_OT), F("Boiler fault reset successfully"));
 
         } else {
@@ -296,7 +311,7 @@ protected:
     // Diag reset action
     if (vars.actions.resetDiagnostic) {
       if (vars.states.diagnostic) {
-        if (ot->sendServiceReset()) {
+        if (this->instance->sendServiceReset()) {
           Log.sinfoln(FPSTR(L_OT), F("Boiler diagnostic reset successfully"));
           
         } else {
@@ -318,7 +333,7 @@ protected:
       Log.sinfoln(FPSTR(L_OT_DHW), F("Set temp = %u"), newDhwTemp);
 
       // Set DHW temp
-      if (ot->setDhwTemp(newDhwTemp)) {
+      if (this->instance->setDhwTemp(newDhwTemp)) {
         currentDhwTemp = newDhwTemp;
         this->dhwSetTempTime = millis();
 
@@ -328,7 +343,7 @@ protected:
 
       // Set DHW temp to CH2
       if (settings.opentherm.dhwToCh2) {
-        if (!ot->setHeatingCh2Temp(newDhwTemp)) {
+        if (!this->instance->setHeatingCh2Temp(newDhwTemp)) {
           Log.swarningln(FPSTR(L_OT_DHW), F("Failed set ch2 temp"));
         }
       }
@@ -340,7 +355,7 @@ protected:
       Log.sinfoln(FPSTR(L_OT_HEATING), F("Set temp = %u"), vars.parameters.heatingSetpoint);
 
       // Set heating temp
-      if (ot->setHeatingCh1Temp(vars.parameters.heatingSetpoint)) {
+      if (this->instance->setHeatingCh1Temp(vars.parameters.heatingSetpoint)) {
         currentHeatingTemp = vars.parameters.heatingSetpoint;
         this->heatingSetTempTime = millis();
 
@@ -350,7 +365,7 @@ protected:
 
       // Set heating temp to CH2
       if (settings.opentherm.heatingCh1ToCh2) {
-        if (!ot->setHeatingCh2Temp(vars.parameters.heatingSetpoint)) {
+        if (!this->instance->setHeatingCh2Temp(vars.parameters.heatingSetpoint)) {
           Log.swarningln(FPSTR(L_OT_HEATING), F("Failed set ch2 temp"));
         }
       }
@@ -373,8 +388,40 @@ protected:
     }
   }
 
+  void initialize() {
+    // Not all boilers support these, only try once when the boiler becomes connected
+    if (updateSlaveVersion()) {
+      Log.straceln(FPSTR(L_OT), F("Slave version: %u, type: %u"), vars.parameters.slaveVersion, vars.parameters.slaveType);
+
+    } else {
+      Log.swarningln(FPSTR(L_OT), F("Get slave version failed"));
+    }
+
+    // 0x013F
+    if (setMasterVersion(0x3F, 0x01)) {
+      Log.straceln(FPSTR(L_OT), F("Master version: %u, type: %u"), vars.parameters.masterVersion, vars.parameters.masterType);
+      
+    } else {
+      Log.swarningln(FPSTR(L_OT), F("Set master version failed"));
+    }
+
+    if (updateSlaveConfig()) {
+      Log.straceln(FPSTR(L_OT), F("Slave member id: %u, flags: %u"), vars.parameters.slaveMemberId, vars.parameters.slaveFlags);
+
+    } else {
+      Log.swarningln(FPSTR(L_OT), F("Get slave config failed"));
+    }
+
+    if (setMasterConfig(settings.opentherm.memberIdCode & 0xFF, (settings.opentherm.memberIdCode & 0xFFFF) >> 8)) {
+      Log.straceln(FPSTR(L_OT), F("Master member id: %u, flags: %u"), vars.parameters.masterMemberId, vars.parameters.masterFlags);
+      
+    } else {
+      Log.swarningln(FPSTR(L_OT), F("Set master config failed"));
+    }
+  }
+
   bool isReady() {
-    return millis() - this->startupTime > this->readyTime;
+    return millis() - this->instanceCreatedTime > this->readyTime;
   }
 
   bool needSetDhwTemp() {
@@ -386,7 +433,7 @@ protected:
   }
 
   bool updateSlaveConfig() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::SConfigSMemberIDcode,
       0
@@ -447,7 +494,7 @@ protected:
       return true;
     }
 
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::WRITE_DATA,
       OpenThermMessageID::MConfigMMemberIDcode,
       request
@@ -457,22 +504,22 @@ protected:
   }
 
   bool setMaxModulationLevel(byte value) {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::WRITE_DATA,
       OpenThermMessageID::MaxRelModLevelSetting,
-      ot->toF88(value)
+      this->instance->toF88(value)
     ));
 
     if (!CustomOpenTherm::isValidResponse(response)) {
       return false;
     }
 
-    vars.parameters.maxModulation = ot->fromF88(response);
+    vars.parameters.maxModulation = this->instance->fromF88(response);
     return true;
   }
 
   bool updateSlaveOtVersion() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::OpenThermVersionSlave,
       0
@@ -487,23 +534,23 @@ protected:
   }
 
   bool setMasterOtVersion(float version) {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::WRITE_DATA,
       OpenThermMessageID::OpenThermVersionMaster,
-      ot->toF88(version)
+      this->instance->toF88(version)
     ));
 
     if (!CustomOpenTherm::isValidResponse(response)) {
       return false;
     }
 
-    vars.parameters.masterOtVersion = ot->fromF88(response);
+    vars.parameters.masterOtVersion = this->instance->fromF88(response);
 
     return true;
   }
 
   bool updateSlaveVersion() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::SlaveVersion,
       0
@@ -520,7 +567,7 @@ protected:
   }
 
   bool setMasterVersion(uint8_t version, uint8_t type) {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::WRITE_DATA,
       OpenThermMessageID::MasterVersion,
       (unsigned int) version | (unsigned int) type << 8
@@ -537,7 +584,7 @@ protected:
   }
 
   bool updateMinMaxDhwTemp() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::TdhwSetUBTdhwSetLB,
       0
@@ -561,7 +608,7 @@ protected:
   }
 
   bool updateMinMaxHeatingTemp() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::MaxTSetUBMaxTSetLB,
       0
@@ -584,7 +631,7 @@ protected:
   }
 
   bool setMaxHeatingTemp(byte value) {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermMessageType::WRITE_DATA,
       OpenThermMessageID::MaxTSet,
       CustomOpenTherm::temperatureToData(value)
@@ -594,7 +641,7 @@ protected:
   }
 
   bool updateOutsideTemp() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::Toutside,
       0
@@ -609,7 +656,7 @@ protected:
   }
 
   bool updateHeatingTemp() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermMessageType::READ_DATA,
       OpenThermMessageID::Tboiler,
       0
@@ -630,7 +677,7 @@ protected:
 
 
   bool updateDhwTemp() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermMessageType::READ_DATA,
       OpenThermMessageID::Tdhw,
       0
@@ -650,7 +697,7 @@ protected:
   }
 
   bool updateDhwFlowRate() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermMessageType::READ_DATA,
       OpenThermMessageID::DHWFlowRate,
       0
@@ -670,7 +717,7 @@ protected:
   }
 
   bool updateFaultCode() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::ASFflags,
       0
@@ -685,7 +732,7 @@ protected:
   }
 
   bool updateModulationLevel() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::RelModLevel,
       0
@@ -695,7 +742,7 @@ protected:
       return false;
     }
 
-    float modulation = ot->fromF88(response);
+    float modulation = this->instance->fromF88(response);
     if (!vars.states.flame) {
       vars.sensors.modulation = 0;
     } else {
@@ -706,7 +753,7 @@ protected:
   }
 
   bool updatePressure() {
-    unsigned long response = ot->sendRequest(CustomOpenTherm::buildRequest(
+    unsigned long response = this->instance->sendRequest(CustomOpenTherm::buildRequest(
       OpenThermRequestType::READ_DATA,
       OpenThermMessageID::CHPressure,
       0
diff --git a/src/SensorsTask.h b/src/SensorsTask.h
index 6098e2b..ad6fca2 100644
--- a/src/SensorsTask.h
+++ b/src/SensorsTask.h
@@ -60,39 +60,38 @@ protected:
   }
 
   void loop() {
-    bool needUpdateIndoorTemp = false;
-    bool needUpdateOutdoorTemp = false;
+    bool indoorTempUpdated = false;
+    bool outdoorTempUpdated = false;
 
-    if (settings.sensors.outdoor.type == 2 && settings.sensors.outdoor.pin) {
+    if (settings.sensors.outdoor.type == 2 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
       outdoorTemperatureSensor();
-      needUpdateOutdoorTemp = true;
+      outdoorTempUpdated = true;
     }
 
-    if (settings.sensors.indoor.type == 2 && settings.sensors.indoor.pin) {
+    if (settings.sensors.indoor.type == 2 && GPIO_IS_VALID(settings.sensors.indoor.gpio)) {
       indoorTemperatureSensor();
-      needUpdateIndoorTemp = true;
+      indoorTempUpdated = true;
     }
-
 #if USE_BLE
-    if (settings.sensors.indoor.type == 3) {
-      bluetoothSensor();
-      needUpdateIndoorTemp = true;
+    else if (settings.sensors.indoor.type == 3) {
+      indoorTemperatureBluetoothSensor();
+      indoorTempUpdated = true;
     }
 #endif
 
-    if (needUpdateOutdoorTemp && fabs(vars.temperatures.outdoor - this->filteredOutdoorTemp) > 0.099) {
+    if (outdoorTempUpdated && fabs(vars.temperatures.outdoor - this->filteredOutdoorTemp) > 0.099) {
       vars.temperatures.outdoor = this->filteredOutdoorTemp + settings.sensors.outdoor.offset;
       Log.sinfoln(FPSTR(L_SENSORS_OUTDOOR), F("New temp: %f"), vars.temperatures.outdoor);
     }
 
-    if (needUpdateIndoorTemp && fabs(vars.temperatures.indoor - this->filteredIndoorTemp) > 0.099) {
+    if (indoorTempUpdated && fabs(vars.temperatures.indoor - this->filteredIndoorTemp) > 0.099) {
       vars.temperatures.indoor = this->filteredIndoorTemp + settings.sensors.indoor.offset;
       Log.sinfoln(FPSTR(L_SENSORS_INDOOR), F("New temp: %f"), vars.temperatures.indoor);
     }
   }
 
 #if USE_BLE
-  void bluetoothSensor() {
+  void indoorTemperatureBluetoothSensor() {
     static bool initBleNotify = false;
     if (!initBleSensor && millis() > 5000) {
       Log.sinfoln(FPSTR(L_SENSORS_BLE), F("Init BLE"));
@@ -210,9 +209,9 @@ protected:
 
   void outdoorTemperatureSensor() {
     if (!this->initOutdoorSensor) {
-      Log.sinfoln(FPSTR(L_SENSORS_OUTDOOR), F("Starting on gpio %hhu..."), settings.sensors.outdoor.pin);
+      Log.sinfoln(FPSTR(L_SENSORS_OUTDOOR), F("Starting on gpio %hhu..."), settings.sensors.outdoor.gpio);
 
-      this->oneWireOutdoorSensor->begin(settings.sensors.outdoor.pin);
+      this->oneWireOutdoorSensor->begin(settings.sensors.outdoor.gpio);
       this->outdoorSensor->begin();
 
       Log.straceln(
@@ -276,9 +275,9 @@ protected:
 
   void indoorTemperatureSensor() {
     if (!this->initIndoorSensor) {
-      Log.sinfoln(FPSTR(L_SENSORS_INDOOR), F("Starting on gpio %hhu..."), settings.sensors.indoor.pin);
+      Log.sinfoln(FPSTR(L_SENSORS_INDOOR), F("Starting on gpio %hhu..."), settings.sensors.indoor.gpio);
 
-      this->oneWireIndoorSensor->begin(settings.sensors.indoor.pin);
+      this->oneWireIndoorSensor->begin(settings.sensors.indoor.gpio);
       this->indoorSensor->begin();
 
       Log.straceln(
diff --git a/src/Settings.h b/src/Settings.h
index 9545ccf..da988fe 100644
--- a/src/Settings.h
+++ b/src/Settings.h
@@ -1,5 +1,5 @@
 struct NetworkSettings {
-  char hostname[25] = HOSTNAME_DEFAULT;
+  char hostname[25] = DEFAULT_HOSTNAME;
   bool useDhcp = true;
 
   struct {
@@ -10,14 +10,14 @@ struct NetworkSettings {
   } staticConfig;
 
   struct {
-    char ssid[33] = AP_SSID_DEFAULT;
-    char password[65] = AP_PASSWORD_DEFAULT;
+    char ssid[33] = DEFAULT_AP_SSID;
+    char password[65] = DEFAULT_AP_PASSWORD;
     byte channel = 6;
   } ap;
 
   struct {
-    char ssid[33] = STA_SSID_DEFAULT;
-    char password[65] = STA_PASSWORD_DEFAULT;
+    char ssid[33] = DEFAULT_STA_SSID;
+    char password[65] = DEFAULT_STA_PASSWORD;
     byte channel = 0;
   } sta;
 } networkSettings;
@@ -31,13 +31,13 @@ struct Settings {
 
   struct {
     bool useAuth = false;
-    char login[13] = PORTAL_LOGIN_DEFAULT;
-    char password[33] = PORTAL_PASSWORD_DEFAULT;
+    char login[13] = DEFAULT_PORTAL_LOGIN;
+    char password[33] = DEFAULT_PORTAL_PASSWORD;
   } portal;
 
   struct {
-    byte inPin = OT_IN_PIN_DEFAULT;
-    byte outPin = OT_OUT_PIN_DEFAULT;
+    byte inGpio = DEFAULT_OT_IN_GPIO;
+    byte outGpio = DEFAULT_OT_OUT_GPIO;
     unsigned int memberIdCode = 0;
     bool dhwPresent = true;
     bool summerWinterMode = false;
@@ -49,11 +49,11 @@ struct Settings {
   } opentherm;
 
   struct {
-    char server[81] = MQTT_SERVER_DEFAULT;
-    unsigned short port = MQTT_PORT_DEFAULT;
-    char user[33] = MQTT_USER_DEFAULT;
-    char password[33] = MQTT_PASSWORD_DEFAULT;
-    char prefix[33] = MQTT_PREFIX_DEFAULT;
+    char server[81] = DEFAULT_MQTT_SERVER;
+    unsigned short port = DEFAULT_MQTT_PORT;
+    char user[33] = DEFAULT_MQTT_USER;
+    char password[33] = DEFAULT_MQTT_PASSWORD;
+    char prefix[33] = DEFAULT_MQTT_PREFIX;
     unsigned short interval = 5;
   } mqtt;
 
@@ -102,14 +102,14 @@ struct Settings {
     struct {
       // 0 - boiler, 1 - manual, 2 - ds18b20
       byte type = 0;
-      byte pin = SENSOR_OUTDOOR_PIN_DEFAULT;
+      byte gpio = DEFAULT_SENSOR_OUTDOOR_GPIO;
       float offset = 0.0f;
     } outdoor;
 
     struct {
       // 1 - manual, 2 - ds18b20, 3 - ble
       byte type = 1;
-      byte pin = SENSOR_INDOOR_PIN_DEFAULT;
+      byte gpio = DEFAULT_SENSOR_INDOOR_GPIO;
       uint8_t bleAddresss[6] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
       float offset = 0.0f;
     } indoor;
@@ -117,7 +117,7 @@ struct Settings {
 
   struct {
     bool use = false;
-    byte pin = EXT_PUMP_PIN_DEFAULT;
+    byte gpio = DEFAULT_EXT_PUMP_GPIO;
     unsigned short postCirculationTime = 600;
     unsigned int antiStuckInterval = 2592000;
     unsigned short antiStuckTime = 300;
diff --git a/src/defines.h b/src/defines.h
index 0e4586d..dc15054 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -4,9 +4,6 @@
 
 #define EMERGENCY_TIME_TRESHOLD     120000
 #define MQTT_RECONNECT_INTERVAL     15000
-#define MQTT_KEEPALIVE              30
-
-#define OPENTHERM_OFFLINE_TRESHOLD  10
 
 #define EXT_SENSORS_INTERVAL        5000
 #define EXT_SENSORS_FILTER_K        0.15
@@ -14,16 +11,12 @@
 #define CONFIG_URL                  "http://%s/"
 #define SETTINGS_VALID_VALUE        "stvalid" // only 8 chars!
 
+#define GPIO_IS_NOT_CONFIGURED      0xff
 #define DEFAULT_HEATING_MIN_TEMP    20
 #define DEFAULT_HEATING_MAX_TEMP    90
 #define DEFAULT_DHW_MIN_TEMP        30
 #define DEFAULT_DHW_MAX_TEMP        60
 
-
-#ifndef WM_DEBUG_MODE
-  #define WM_DEBUG_MODE WM_DEBUG_NOTIFY
-#endif
-
 #ifndef USE_SERIAL
   #define USE_SERIAL true
 #endif
@@ -36,80 +29,86 @@
   #define USE_BLE false
 #endif
 
-#ifndef HOSTNAME_DEFAULT
-  #define HOSTNAME_DEFAULT "opentherm"
+#ifndef DEFAULT_HOSTNAME
+  #define DEFAULT_HOSTNAME "opentherm"
 #endif
 
-#ifndef AP_SSID_DEFAULT
-  #define AP_SSID_DEFAULT "OpenTherm Gateway"
+#ifndef DEFAULT_AP_SSID
+  #define DEFAULT_AP_SSID "OpenTherm Gateway"
 #endif
 
-#ifndef AP_PASSWORD_DEFAULT
-  #define AP_PASSWORD_DEFAULT "otgateway123456"
+#ifndef DEFAULT_AP_PASSWORD
+  #define DEFAULT_AP_PASSWORD "otgateway123456"
 #endif
 
-#ifndef STA_SSID_DEFAULT
-  #define STA_SSID_DEFAULT ""
+#ifndef DEFAULT_STA_SSID
+  #define DEFAULT_STA_SSID ""
 #endif
 
-#ifndef STA_PASSWORD_DEFAULT
-  #define STA_PASSWORD_DEFAULT ""
+#ifndef DEFAULT_STA_PASSWORD
+  #define DEFAULT_STA_PASSWORD ""
 #endif
 
 #ifndef DEBUG_BY_DEFAULT
   #define DEBUG_BY_DEFAULT false
 #endif
 
-#ifndef PORTAL_LOGIN_DEFAULT
-  #define PORTAL_LOGIN_DEFAULT ""
+#ifndef DEFAULT_PORTAL_LOGIN
+  #define DEFAULT_PORTAL_LOGIN ""
 #endif
 
-#ifndef PORTAL_PASSWORD_DEFAULT
-  #define PORTAL_PASSWORD_DEFAULT ""
+#ifndef DEFAULT_PORTAL_PASSWORD
+  #define DEFAULT_PORTAL_PASSWORD ""
 #endif
 
-#ifndef MQTT_SERVER_DEFAULT
-  #define MQTT_SERVER_DEFAULT ""
+#ifndef DEFAULT_MQTT_SERVER
+  #define DEFAULT_MQTT_SERVER ""
 #endif
 
-#ifndef MQTT_PORT_DEFAULT
-  #define MQTT_PORT_DEFAULT 1883
+#ifndef DEFAULT_MQTT_PORT
+  #define DEFAULT_MQTT_PORT 1883
 #endif
 
-#ifndef MQTT_USER_DEFAULT
-  #define MQTT_USER_DEFAULT ""
+#ifndef DEFAULT_MQTT_USER
+  #define DEFAULT_MQTT_USER ""
 #endif
 
-#ifndef MQTT_PASSWORD_DEFAULT
-  #define MQTT_PASSWORD_DEFAULT ""
+#ifndef DEFAULT_MQTT_PASSWORD
+  #define DEFAULT_MQTT_PASSWORD ""
 #endif
 
-#ifndef MQTT_PREFIX_DEFAULT
-  #define MQTT_PREFIX_DEFAULT "opentherm"
+#ifndef DEFAULT_MQTT_PREFIX
+  #define DEFAULT_MQTT_PREFIX "opentherm"
 #endif
 
-#ifndef OT_IN_PIN_DEFAULT
-  #define OT_IN_PIN_DEFAULT 0
+#ifndef DEFAULT_OT_IN_GPIO
+  #define DEFAULT_OT_IN_GPIO GPIO_IS_NOT_CONFIGURED
 #endif
 
-#ifndef OT_OUT_PIN_DEFAULT
-  #define OT_OUT_PIN_DEFAULT 0
+#ifndef DEFAULT_OT_OUT_GPIO
+  #define DEFAULT_OT_OUT_GPIO GPIO_IS_NOT_CONFIGURED
 #endif
 
-#ifndef SENSOR_OUTDOOR_PIN_DEFAULT
-  #define SENSOR_OUTDOOR_PIN_DEFAULT 0
+#ifndef DEFAULT_SENSOR_OUTDOOR_GPIO
+  #define DEFAULT_SENSOR_OUTDOOR_GPIO GPIO_IS_NOT_CONFIGURED
 #endif
 
-#ifndef SENSOR_INDOOR_PIN_DEFAULT
-  #define SENSOR_INDOOR_PIN_DEFAULT 0
+#ifndef DEFAULT_SENSOR_INDOOR_GPIO
+  #define DEFAULT_SENSOR_INDOOR_GPIO GPIO_IS_NOT_CONFIGURED
 #endif
 
-#ifndef EXT_PUMP_PIN_DEFAULT
-  #define EXT_PUMP_PIN_DEFAULT 0
+#ifndef DEFAULT_EXT_PUMP_GPIO
+  #define DEFAULT_EXT_PUMP_GPIO GPIO_IS_NOT_CONFIGURED
 #endif
 
 #ifndef PROGMEM
   #define PROGMEM 
 #endif
 
+#ifndef GPIO_IS_VALID_GPIO
+  #define GPIO_IS_VALID_GPIO(gpioNum) (gpioNum >= 0 && gpioNum <= 16)
+#endif
+
+#define GPIO_IS_VALID(gpioNum) (gpioNum != GPIO_IS_NOT_CONFIGURED && GPIO_IS_VALID_GPIO(gpioNum))
+
 char buffer[255];
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index 0aa1fef..46a10cb 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -143,7 +143,7 @@ void setup() {
   tMqtt = new MqttTask(false, 500);
   Scheduler.start(tMqtt);
 
-  tOt = new OpenThermTask(false, 750);
+  tOt = new OpenThermTask(true, 750);
   Scheduler.start(tOt);
 
   tSensors = new SensorsTask(true, EXT_SENSORS_INTERVAL);
diff --git a/src/utils.h b/src/utils.h
index 1d71eb5..fac36e0 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -273,8 +273,8 @@ void settingsToJson(const Settings& src, JsonVariant dst, bool safe = false) {
     dst["portal"]["login"] = src.portal.login;
     dst["portal"]["password"] = src.portal.password;
 
-    dst["opentherm"]["inPin"] = src.opentherm.inPin;
-    dst["opentherm"]["outPin"] = src.opentherm.outPin;
+    dst["opentherm"]["inGpio"] = src.opentherm.inGpio;
+    dst["opentherm"]["outGpio"] = src.opentherm.outGpio;
     dst["opentherm"]["memberIdCode"] = src.opentherm.memberIdCode;
     dst["opentherm"]["dhwPresent"] = src.opentherm.dhwPresent;
     dst["opentherm"]["summerWinterMode"] = src.opentherm.summerWinterMode;
@@ -324,11 +324,11 @@ void settingsToJson(const Settings& src, JsonVariant dst, bool safe = false) {
   dst["equitherm"]["t_factor"] = roundd(src.equitherm.t_factor, 3);
 
   dst["sensors"]["outdoor"]["type"] = src.sensors.outdoor.type;
-  dst["sensors"]["outdoor"]["pin"] = src.sensors.outdoor.pin;
+  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"]["pin"] = src.sensors.indoor.pin;
+  dst["sensors"]["indoor"]["gpio"] = src.sensors.indoor.gpio;
 
   char bleAddress[18];
   sprintf(
@@ -346,7 +346,7 @@ void settingsToJson(const Settings& src, JsonVariant dst, bool safe = false) {
 
   if (!safe) {
     dst["externalPump"]["use"] = src.externalPump.use;
-    dst["externalPump"]["pin"] = src.externalPump.pin;
+    dst["externalPump"]["gpio"] = src.externalPump.gpio;
     dst["externalPump"]["postCirculationTime"] = roundd(src.externalPump.postCirculationTime / 60, 0);
     dst["externalPump"]["antiStuckInterval"] = roundd(src.externalPump.antiStuckInterval / 86400, 0);
     dst["externalPump"]["antiStuckTime"] = roundd(src.externalPump.antiStuckTime / 60, 0);
@@ -404,21 +404,37 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
 
 
     // opentherm
-    if (!src["opentherm"]["inPin"].isNull()) {
-      unsigned char value = src["opentherm"]["inPin"].as<unsigned char>();
+    if (!src["opentherm"]["inGpio"].isNull()) {
+      if (src["opentherm"]["inGpio"].is<JsonString>() && src["opentherm"]["inGpio"].as<JsonString>().size() == 0) {
+        if (dst.opentherm.inGpio != GPIO_IS_NOT_CONFIGURED) {
+          dst.opentherm.inGpio = GPIO_IS_NOT_CONFIGURED;
+          changed = true;
+        }
+        
+      } else {
+        unsigned char value = src["opentherm"]["inGpio"].as<unsigned char>();
 
-      if (value >= 0 && value < 50) {
-        dst.opentherm.inPin = value;
-        changed = true;
+        if (value >= 0 && value <= 254) {
+          dst.opentherm.inGpio = value;
+          changed = true;
+        }
       }
     }
     
-    if (!src["opentherm"]["outPin"].isNull()) {
-      unsigned char value = src["opentherm"]["outPin"].as<unsigned char>();
+    if (!src["opentherm"]["outGpio"].isNull()) {
+      if (src["opentherm"]["outGpio"].is<JsonString>() && src["opentherm"]["outGpio"].as<JsonString>().size() == 0) {
+        if (dst.opentherm.outGpio != GPIO_IS_NOT_CONFIGURED) {
+          dst.opentherm.outGpio = GPIO_IS_NOT_CONFIGURED;
+          changed = true;
+        }
+        
+      } else {
+        unsigned char value = src["opentherm"]["outGpio"].as<unsigned char>();
 
-      if (value >= 0 && value < 50) {
-        dst.opentherm.outPin = value;
-        changed = true;
+        if (value >= 0 && value <= 254) {
+          dst.opentherm.outGpio = value;
+          changed = true;
+        }
       }
     }
 
@@ -789,12 +805,20 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
     }
   }
 
-  if (!src["sensors"]["outdoor"]["pin"].isNull()) {
-    unsigned char value = src["sensors"]["outdoor"]["pin"].as<unsigned char>();
+  if (!src["sensors"]["outdoor"]["gpio"].isNull()) {
+    if (src["sensors"]["outdoor"]["gpio"].is<JsonString>() && src["sensors"]["outdoor"]["gpio"].as<JsonString>().size() == 0) {
+      if (dst.sensors.outdoor.gpio != GPIO_IS_NOT_CONFIGURED) {
+        dst.sensors.outdoor.gpio = GPIO_IS_NOT_CONFIGURED;
+        changed = true;
+      }
+      
+    } else {
+      unsigned char value = src["sensors"]["outdoor"]["gpio"].as<unsigned char>();
 
-    if (value >= 0 && value <= 50) {
-      dst.sensors.outdoor.pin = value;
-      changed = true;
+      if (value >= 0 && value <= 254) {
+        dst.sensors.outdoor.gpio = value;
+        changed = true;
+      }
     }
   }
 
@@ -821,12 +845,20 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
     }
   }
 
-  if (!src["sensors"]["indoor"]["pin"].isNull()) {
-    unsigned char value = src["sensors"]["indoor"]["pin"].as<unsigned char>();
-
-    if (value >= 0 && value <= 50) {
-      dst.sensors.indoor.pin = value;
-      changed = true;
+  if (!src["sensors"]["indoor"]["gpio"].isNull()) {
+    if (src["sensors"]["indoor"]["gpio"].is<JsonString>() && src["sensors"]["indoor"]["gpio"].as<JsonString>().size() == 0) {
+      if (dst.sensors.indoor.gpio != GPIO_IS_NOT_CONFIGURED) {
+        dst.sensors.indoor.gpio = GPIO_IS_NOT_CONFIGURED;
+        changed = true;
+      }
+      
+    } else {
+      unsigned char value = src["sensors"]["indoor"]["gpio"].as<unsigned char>();
+      
+      if (value >= 0 && value <= 254) {
+        dst.sensors.indoor.gpio = value;
+        changed = true;
+      }
     }
   }
 
@@ -861,12 +893,20 @@ bool jsonToSettings(const JsonVariantConst src, Settings& dst, bool safe = false
       changed = true;
     }
 
-    if (!src["externalPump"]["pin"].isNull()) {
-      unsigned char value = src["externalPump"]["pin"].as<unsigned char>();
+    if (!src["externalPump"]["gpio"].isNull()) {
+      if (src["externalPump"]["gpio"].is<JsonString>() && src["externalPump"]["gpio"].as<JsonString>().size() == 0) {
+        if (dst.externalPump.gpio != GPIO_IS_NOT_CONFIGURED) {
+          dst.externalPump.gpio = GPIO_IS_NOT_CONFIGURED;
+          changed = true;
+        }
+        
+      } else {
+        unsigned char value = src["externalPump"]["gpio"].as<unsigned char>();
 
-      if (value >= 0 && value <= 50) {
-        dst.externalPump.pin = value;
-        changed = true;
+        if (value >= 0 && value <= 254) {
+          dst.externalPump.gpio = value;
+          changed = true;
+        }
       }
     }
 
diff --git a/src_data/static/app.js b/src_data/static/app.js
index d46ea1d..97b8807 100644
--- a/src_data/static/app.js
+++ b/src_data/static/app.js
@@ -491,8 +491,8 @@ async function loadSettings() {
   setInputValue('.portal-password', result.portal.password);
   setBusy('#portal-settings-busy', '#portal-settings', false);
 
-  setInputValue('.opentherm-in-pin', result.opentherm.inPin);
-  setInputValue('.opentherm-out-pin', result.opentherm.outPin);
+  setInputValue('.opentherm-in-gpio', result.opentherm.inGpio < 255 ? result.opentherm.inGpio : '');
+  setInputValue('.opentherm-out-gpio', result.opentherm.outGpio < 255 ? result.opentherm.outGpio : '');
   setInputValue('.opentherm-member-id-code', result.opentherm.memberIdCode);
   setCheckboxValue('.opentherm-dhw-present', result.opentherm.dhwPresent);
   setCheckboxValue('.opentherm-sw-mode', result.opentherm.summerWinterMode);
@@ -512,18 +512,18 @@ async function loadSettings() {
   setBusy('#mqtt-settings-busy', '#mqtt-settings', false);
 
   setRadioValue('.outdoor-sensor-type', result.sensors.outdoor.type);
-  setInputValue('.outdoor-sensor-pin', result.sensors.outdoor.pin);
+  setInputValue('.outdoor-sensor-gpio', result.sensors.outdoor.gpio  < 255 ? result.sensors.outdoor.gpio : '');
   setInputValue('.outdoor-sensor-offset', result.sensors.outdoor.offset);
   setBusy('#outdoor-sensor-settings-busy', '#outdoor-sensor-settings', false);
 
   setRadioValue('.indoor-sensor-type', result.sensors.indoor.type);
-  setInputValue('.indoor-sensor-pin', result.sensors.indoor.pin);
+  setInputValue('.indoor-sensor-gpio', result.sensors.indoor.gpio < 255 ? result.sensors.indoor.gpio : '');
   setInputValue('.indoor-sensor-offset', result.sensors.indoor.offset);
   setInputValue('.indoor-sensor-ble-addresss', result.sensors.indoor.bleAddresss);
   setBusy('#indoor-sensor-settings-busy', '#indoor-sensor-settings', false);
 
   setCheckboxValue('.extpump-use', result.externalPump.use);
-  setInputValue('.extpump-pin', result.externalPump.pin);
+  setInputValue('.extpump-gpio', result.externalPump.gpio < 255 ? result.externalPump.gpio : '');
   setInputValue('.extpump-pc-time', result.externalPump.postCirculationTime);
   setInputValue('.extpump-as-interval', result.externalPump.antiStuckInterval);
   setInputValue('.extpump-as-time', result.externalPump.antiStuckTime);