Index: firmware/App/Controllers/Heaters.c
===================================================================
diff -u -re12eefac42a3806a34f3ddac6df30bbb5ca51f6f -r1644c24b0b51661ceaba579e5ebee0d1d5bad85f
--- firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision e12eefac42a3806a34f3ddac6df30bbb5ca51f6f)
+++ firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 1644c24b0b51661ceaba579e5ebee0d1d5bad85f)
@@ -373,10 +373,18 @@
         heatersStatus[ heater ].heaterOnState               = FALSE;
         control[ heater ].data                              = HEATERS_MIN_DUTY_CYCLE;
         heatersStatus[ heater ].state                       = HEATER_EXEC_STATE_OFF;
-        heatersStatus[ D5_HEAT ].controlIntervalCounter     = D5_HEAT_CONTROL_INTERVAL_START_COUNT;
-        heatersStatus[ D45_HEAT ].controlIntervalCounter    = 0;
         startupHeaterControl                                = TRUE;
 
+        //Update control interval counter
+        if ( D5_HEAT == heater )
+        {
+            heatersStatus[ D5_HEAT ].controlIntervalCounter = D5_HEAT_CONTROL_INTERVAL_START_COUNT;
+        }
+        else
+        {
+            heatersStatus[ D45_HEAT ].controlIntervalCounter = 0;
+        }
+
         // update duty cycle
         setHeaterControl( heater );
     }
@@ -608,7 +616,7 @@
     F32 measuredTemperature  = 0.0F;
     F32 ctrl                 = 0.0F;
 
-    if( ++heatersStatus[ heater ].controlIntervalCounter > controlInterval[ heater ] )
+    if ( ++heatersStatus[ heater ].controlIntervalCounter >= controlInterval[ heater ] )
     {
         if ( D5_HEAT == heater )
         {
@@ -619,9 +627,9 @@
             if ( TRUE == startupHeaterControl )
             {
                 startupHeaterControl    = FALSE;
+                F32 deltaTempC          = targetTemperature - inletTemperature;
                 //TODO : testing
-                //F32 deltaTempC          = targetTemperature - inletTemperature;
-                F32 deltaTempC          = 10.0F;          // Hard code for testing, later remove it.
+                //F32 deltaTempC          = 10.0F;          // Hard code for testing, later remove it.
                 F32 capDeltaTempC       = MAX( deltaTempC, HEATERS_ZERO_DELTA_TEMP_C );
                 F32 flowrate            = getTDDialysateFlowrate() / LITER_IN_ML ;
                 F32 feedforward         = calculateDutyCycle( flowrate, capDeltaTempC, PRIMARY_HEATER_MAX_PWR_WATTS, AC_HEATER_EFFICIENCY,