Index: firmware/App/Controllers/Heaters.c
===================================================================
diff -u -r0df32171c99e44512f8ea90ab2068e25ef4bcce2 -r1781335a8c1833fad17b275bf44c7f6675e68423
--- firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 0df32171c99e44512f8ea90ab2068e25ef4bcce2)
+++ firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 1781335a8c1833fad17b275bf44c7f6675e68423)
@@ -49,11 +49,15 @@
 #define HEATERS_ZERO_DELTA_TEMP_C                                  0.0F                                                            ///< Heaters zero delta temperature in C.
 #define HEATERS_DUTY_CYCLE_CONVERSION_FACTOR                       100.0F                                                          ///< Heaters duty cycle 0: OFF, 100: 100% duty cycle.
 #define HEATERS_ZERO_EFFICIENCY                                    0.0F                                                            ///< Zero heater efficiency
+#define HEATER_CNTL_TRANSFER_DELTA_TEMP_C                          0.25F                                                           ///< AC heater delta temperature to transfer control from open to close loop
 
 #define D5_HEAT_TX_INIT_FEED_FORWARD                               0.0F                                                            ///< Initial Feed forward term for heater control
-#define D5_HEAT_TX_P_COEFFICIENT                                   0.050F                                                          ///< P Term for AC primary heater control during treatment mode.
-#define D5_HEAT_TX_I_COEFFICIENT                                   0.015F                                                          ///< I Term for AC primary heater control during treatment mode.
+//#define D5_HEAT_TX_P_COEFFICIENT                                   0.050F                                                          ///< P Term for AC primary heater control during treatment mode.
+//#define D5_HEAT_TX_I_COEFFICIENT                                   0.015F                                                          ///< I Term for AC primary heater control during treatment mode.
 
+#define D5_HEAT_TX_P_COEFFICIENT                                   0.048F                                                          ///< P Term for AC primary heater control during treatment mode.
+#define D5_HEAT_TX_I_COEFFICIENT                                   0.012F                                                          ///< I Term for AC primary heater control during treatment mode.
+
 #define D45_HEAT_P_COEFFICIENT                                     0.20F                                                           ///< P Term for trimmer heater control.
 #define D45_HEAT_I_COEFFICIENT                                     0.05F                                                           ///< I Term for trimmer heater control.
 #define D45_HEAT_TX_INIT_FEED_FORWARD                              0.0F                                                            ///< Initial Feed forward term for heater control
@@ -68,8 +72,10 @@
 #define HEATERS_MAX_OPERATING_VOLTAGE_V                            24.0F                                                           ///< Heaters max operating voltage in volts.
 #define HEATERS_VOLTAGE_OUT_OF_RANGE_TIMEOUT_MS                    ( 2 * MS_PER_SECOND )                                           ///< Heaters voltage out of range time out in milliseconds.
 #define HEATERS_MAX_VOLTAGE_OUT_OF_RANGE_TOL                       0.2F                                                            ///< Heaters max voltage out of range tolerance.
+#define D5_HEATER_DEADBAND_CONTROL                                 0.1F                                                            ///< Heater deadband range for conrtol.
 
-#define D5_HEAT_CONTROL_INTERVAL_MS                                30000                                                           /// Primary heater control interval in milli seconds
+//#define D5_HEAT_CONTROL_INTERVAL_MS                                30000                                                           /// Primary heater control interval in milli seconds
+#define D5_HEAT_CONTROL_INTERVAL_MS                                3000                                                            /// Primary heater control interval in milli seconds
 #define D5_HEAT_CONTROL_INTERVAL_COUNT                             ( D5_HEAT_CONTROL_INTERVAL_MS / TASK_GENERAL_INTERVAL )         ///< Primary heater control interval count.
 #define D45_HEAT_CONTROL_INTERVAL_MS                               ( 1 * MS_PER_SECOND )                                           ///< Trimmer heater control interval in milli seconds
 #define D45_HEAT_CONTROL_INTERVAL_COUNT                            ( D45_HEAT_CONTROL_INTERVAL_MS / TASK_GENERAL_INTERVAL )        ///< Trimmer heater control interval count.
@@ -83,7 +89,6 @@
 #define AC_HEATER_EFFICIENCY                                       0.90F                                                           ///< Approximated AC heater efficiency to be used in energy calcualtions.
 #define DC_HEATER_EFFICIENCY                                       1.0F                                                            ///< DC heater efficiency
 #define D5_HEAT_CONTROL_INTERVAL_START_COUNT                       ( D5_HEAT_CONTROL_INTERVAL_COUNT - 10 )                         ///< AC heater control interval start count to jump feedforward control from open loop.
-
 #define DATA_PUBLISH_COUNTER_START_COUNT                           70                                                              ///< Data publish counter start count.
 
 //static const F32 HEATERS_VOLTAGE_TOLERANCE_V            = HEATERS_MAX_OPERATING_VOLTAGE_V * HEATERS_MAX_VOLTAGE_OUT_OF_RANGE_TOL;  ///< Heaters voltage tolerance in volts.
@@ -555,10 +560,10 @@
 
         if ( DD_MODE_HEAT != opMode )
         {
-            F32 deltaTempC    = targetTemperature - measuredTemperature;
-            F32 capDeltaTempC = MAX( deltaTempC, HEATERS_ZERO_DELTA_TEMP_C );
+            F32 deltaTempC          = targetTemperature - measuredTemperature;
+            F32 capDeltaTempC       = MAX( deltaTempC, HEATERS_ZERO_DELTA_TEMP_C );
 
-            if ( capDeltaTempC <= HEATER_TEMP_CONTROL_TRANSFER )
+            if ( capDeltaTempC <= HEATER_CNTL_TRANSFER_DELTA_TEMP_C )
             {
                 // Transfer Control to target when delta temp is minimal.
                 state = HEATER_EXEC_STATE_CONTROL_TO_TARGET;
@@ -637,8 +642,6 @@
             {
                 startupHeaterControl    = FALSE;
                 F32 deltaTempC          = targetTemperature - inletTemperature;
-                //TODO : testing
-                //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,
@@ -648,8 +651,13 @@
             }
             else
             {
-                ctrl = runPIController( PI_CONTROLLER_ID_D5_HEAT, targetTemperature, measuredTemperature );
-                control[ heater ].data = ctrl;
+                F32 deltaTempC          = fabs( targetTemperature - measuredTemperature );
+
+                if ( deltaTempC >= D5_HEATER_DEADBAND_CONTROL )
+                {
+                    ctrl = runPIController( PI_CONTROLLER_ID_D5_HEAT, targetTemperature, measuredTemperature );
+                    control[ heater ].data = ctrl;
+                }
             }
 #ifdef __HEATERS_DEBUG__
             U32 i;