Index: firmware/App/Controllers/Heaters.c
===================================================================
diff -u -re803f3e6d135641015dc78e2aeac0a5489c9492c -r325e67dab10f6666702bf0f1256015b31e58de4f
--- firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision e803f3e6d135641015dc78e2aeac0a5489c9492c)
+++ firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 325e67dab10f6666702bf0f1256015b31e58de4f)
@@ -41,6 +41,7 @@
  */
 
 // ********** private definitions **********
+
 #define AC_HEATER_TX_MAX_DUTY_CYCLE                                0.50F                                                           ///< AC Heater treatment mode max duty cycle (50% of 1400W : 700W )
 #define AC_HEATER_HEAT_MAX_DUTY_CYCLE                              0.70F                                                           ///< AC Heater heat disinfect mode max duty cycle (70% of 1400W : 980W )
 #define AC_HEATER_MAX_DUTY_CYCLE                                   1.0F                                                            ///< AC Heater max duty cycle (100.0%) or ON state
@@ -120,6 +121,8 @@
     F32 temperature;                                                                                                                ///< Temperature range ( 10.0 to 90.0 deg )
 } HEATER_START_CMD_PAYLOAD_T;
 
+// ********** private data **********
+
 static HEATER_STATUS_T heatersStatus[ NUM_OF_DD_HEATERS ];                                                                         ///< Heaters status.
 static OVERRIDE_F32_T targetTempC[ NUM_OF_DD_HEATERS ];                                                                            ///< Heater target temperature.
 static OVERRIDE_F32_T control[ NUM_OF_DD_HEATERS ];                                                                                ///< Heater control ( Primary : On/Off, Trimmer : Dutycycle).
@@ -140,6 +143,7 @@
 #ifdef __HEATERS_DEBUG__
 static F32 pIControlSignal[ NUM_OF_CONTROLLER_SIGNAL ];
 #endif
+
 // ********** private function prototypes **********
 
 static HEATERS_STATE_T handleHeaterStateOff( DD_HEATERS_T heater );
@@ -738,7 +742,7 @@
         {
             measuredTemperature = getD4AverageTemperature();
             // Inlet temperature post heat exchanger
-            inletTemperature    = getTemperatureValue( X6_TEMP );
+            inletTemperature    = getTemperatureValue( D78_TEMP );
 
             if ( TRUE == startupHeaterControl )
             {