diff --git a/platformio.ini b/platformio.ini
index 747006030..1c0fd31b0 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -112,3 +112,4 @@ build_flags = ${common.build_flags} ${common.custom_flags}
 extra_scripts = 
   pre:scripts/pre_script.py
   scripts/main_script.py
+  
diff --git a/src/ems.cpp b/src/ems.cpp
index 5ad2c6048..03f65ad2c 100644
--- a/src/ems.cpp
+++ b/src/ems.cpp
@@ -1037,11 +1037,10 @@ void ems_setWarmWaterCirculation(bool activated) {
     EMS_TxTelegram.action        = EMS_TX_TELEGRAM_WRITE;
     EMS_TxTelegram.dest          = EMS_Boiler.device_id;
     EMS_TxTelegram.type          = EMS_TYPE_UBAFlags;
-    EMS_TxTelegram.offset        = EMS_OFFSET_UBAParameterWW_wwOneTime;
-    EMS_TxTelegram.length        = EMS_MIN_TELEGRAM_LENGTH+1;
+    EMS_TxTelegram.offset        = EMS_OFFSET_UBAParameterWW_wwCirulation;
+    EMS_TxTelegram.length        = EMS_MIN_TELEGRAM_LENGTH;
     EMS_TxTelegram.type_validate = EMS_ID_NONE;               // don't validate
-    EMS_TxTelegram.data[4]       = 0x11;
-    EMS_TxTelegram.data[5]       = (activated ? 0x33 : 0x11); 
+    EMS_TxTelegram.dataValue     = (activated ? 0x22 : 0x02); 
 
     EMS_TxQueue.push(EMS_TxTelegram);
 }
diff --git a/src/ems_devices.h b/src/ems_devices.h
index 9d65b40c4..c780b0c37 100644
--- a/src/ems_devices.h
+++ b/src/ems_devices.h
@@ -46,6 +46,7 @@
 #define EMS_OFFSET_UBAParameterWW_wwtemp 2                  // WW Temperature
 #define EMS_OFFSET_UBAParameterWW_wwactivated 1             // WW Activated
 #define EMS_OFFSET_UBAParameterWW_wwOneTime 0x00            // WW OneTime loading
+#define EMS_OFFSET_UBAParameterWW_wwCirulation 1             // WW circulation
 #define EMS_OFFSET_UBAParameterWW_wwComfort 9               // WW is in comfort or eco mode
 #define EMS_VALUE_UBAParameterWW_wwComfort_Hot 0x00         // the value for hot
 #define EMS_VALUE_UBAParameterWW_wwComfort_Eco 0xD8         // the value for eco