Index: firmware/App/Modes/ModeHeatDisinfect.c
===================================================================
diff -u -r9c8b132dfff7ad0ef4973698e14d673b9d72a92b -rcb4d35cc50df2d3cc9e828cd92e53cf456ca9b9d
--- firmware/App/Modes/ModeHeatDisinfect.c	(.../ModeHeatDisinfect.c)	(revision 9c8b132dfff7ad0ef4973698e14d673b9d72a92b)
+++ firmware/App/Modes/ModeHeatDisinfect.c	(.../ModeHeatDisinfect.c)	(revision cb4d35cc50df2d3cc9e828cd92e53cf456ca9b9d)
@@ -45,8 +45,6 @@
  *  @{
  */
 
-// TODO add the cooling, test the higher target flow to reduce the gradient
-
 // ********** private definitions **********
 
 // General defines
@@ -140,6 +138,13 @@
     NUM_OF_HEAT_DISINFECT_STATUS                                                                               ///< Number of heat disinfect status.
 } HEAT_DISINFECT_STATUS_T;
 
+/// Non-volatile write structure
+typedef struct
+{
+    BOOL hasDisStatusBeenWrittenToNV;                                                                          ///< Boolean flag to indicate whether the disinfect status been written to NV or not.
+    BOOL hasDisCompleteDateBeenWrittenToNV;                                                                    ///< Boolean flag to indicate whether the disinfect complete date been written to NV or not.
+} DISINFECT_NV_OPS_T;
+
 // ********** private data **********
 
 static DG_HEAT_DISINFECT_STATE_T heatDisinfectState = DG_HEAT_DISINFECT_STATE_START;                           ///< Current active heat disinfect state.
@@ -171,6 +176,7 @@
 static U32 targetDisinfectTime = 0;                                                                            ///< Target disinfect time.
 static BOOL haveDrainParamsBeenInit[ NUM_OF_DG_RESERVOIRS ];                                                   ///< Boolean flag to indicate whether the drain parameters have been reset or not.
 static U32 tempGradOutOfRangeTimer;                                                                            ///< Temperature gradient out of range start timer.
+static DISINFECT_NV_OPS_T disinfectNVOps;                                                                      ///< Disinfect non-volatile memory operations.
 
 // ********** private function prototypes **********
 
@@ -204,6 +210,7 @@
 static HEAT_DISINFECT_STATUS_T getHeatDisinfectStatus( void );
 static void publishHeatDisinfectData( void );
 static void monitorModeHeatDisinfect( void );
+static void writeDisinfectDataToNV( void );
 
 /*********************************************************************//**
  * @brief
@@ -217,35 +224,37 @@
  * isPartialDisinfectInProgress, isDrainPumpOnInMixDrain,
  * hasROFCirculationBeenStarted, ROFCirculationTimer, targetDisinfectTime
  * ROFCirculationCoolingCounter, concentratePumpsPrimeTimer,
- * haveDrainParamsBeenInit, tempGradOutOfRangeTimer
+ * haveDrainParamsBeenInit, tempGradOutOfRangeTimer, disinfectNVOps
  * @return none
  *************************************************************************/
 void initHeatDisinfectMode( void )
 {
-    heatDisinfectState                          = DG_HEAT_DISINFECT_STATE_START;
-    prevHeatDisinfectState                      = DG_HEAT_DISINFECT_STATE_START;
-    heatDisinfectUIState                        = HEAT_DISINFECT_UI_STATE_NOT_RUNNING;
-    stateTimer                                  = 0;
-    isThisLastDrain                             = FALSE;
-    stateTrialCounter                           = 0;
-    areTempSensorsInRange                       = FALSE;
-    rsrvr1Status                                = NUM_OF_DG_RESERVOIR_STATUS;
-    rsrvr2Status                                = NUM_OF_DG_RESERVOIR_STATUS;
-    R1HeatDisinfectVol                          = 0.0;
-    R2HeatDisinfectVol                          = 0.0;
-    overallHeatDisinfectTimer                   = 0;
-    cancellationMode                            = CANCELLATION_MODE_NONE;
-    rsrvrFillStableTimeCounter                  = 0;
-    isPartialDisinfectInProgress                = FALSE;
-    isDrainPumpInMixDrainOn                     = FALSE;
-    ROFCirculationTimer                         = 0;
-    ROFCoolingTimer                             = 0;
-    hasROFCirculationBeenStarted                = FALSE;
-    concentratePumpsPrimeTimer                  = 0;
-    targetDisinfectTime                         = 0;
-    haveDrainParamsBeenInit[ DG_RESERVOIR_1 ]   = FALSE;
-    haveDrainParamsBeenInit[ DG_RESERVOIR_2 ]   = FALSE;
-    tempGradOutOfRangeTimer                     = 0;
+    heatDisinfectState                               = DG_HEAT_DISINFECT_STATE_START;
+    prevHeatDisinfectState                           = DG_HEAT_DISINFECT_STATE_START;
+    heatDisinfectUIState                             = HEAT_DISINFECT_UI_STATE_NOT_RUNNING;
+    stateTimer                                       = 0;
+    isThisLastDrain                                  = FALSE;
+    stateTrialCounter                                = 0;
+    areTempSensorsInRange                            = FALSE;
+    rsrvr1Status                                     = NUM_OF_DG_RESERVOIR_STATUS;
+    rsrvr2Status                                     = NUM_OF_DG_RESERVOIR_STATUS;
+    R1HeatDisinfectVol                               = 0.0;
+    R2HeatDisinfectVol                               = 0.0;
+    overallHeatDisinfectTimer                        = 0;
+    cancellationMode                                 = CANCELLATION_MODE_NONE;
+    rsrvrFillStableTimeCounter                       = 0;
+    isPartialDisinfectInProgress                     = FALSE;
+    isDrainPumpInMixDrainOn                          = FALSE;
+    ROFCirculationTimer                              = 0;
+    ROFCoolingTimer                                  = 0;
+    hasROFCirculationBeenStarted                     = FALSE;
+    concentratePumpsPrimeTimer                       = 0;
+    targetDisinfectTime                              = 0;
+    haveDrainParamsBeenInit[ DG_RESERVOIR_1 ]        = FALSE;
+    haveDrainParamsBeenInit[ DG_RESERVOIR_2 ]        = FALSE;
+    tempGradOutOfRangeTimer                          = 0;
+    disinfectNVOps.hasDisCompleteDateBeenWrittenToNV = FALSE;
+    disinfectNVOps.hasDisStatusBeenWrittenToNV       = FALSE;
 }
 
 /*********************************************************************//**
@@ -1228,10 +1237,6 @@
             stopHeater( DG_TRIMMER_HEATER );
             stateTimer = getMSTimerCount();
             state      = DG_HEAT_DISINFECT_STATE_COOL_DOWN_HEATERS;
-
-            // Set the disinfect flags
-            setDisinfectStatus( TRUE );
-            setLastDisinfectDate( USAGE_INFO_HEAT_DISINFECT, getRTCTimestamp() );
             break;
 
         case HEAT_DISINFECT_HEAT_UP_IN_PROGRESS:
@@ -1259,6 +1264,8 @@
     // Set the heat disinfect UI state
     heatDisinfectUIState = HEAT_DISINFECT_UI_STATE_COOL_DOWN_DEVICE;
 
+    writeDisinfectDataToNV();
+
     if ( TRUE == didTimeout( stateTimer, POST_HEAT_DISINFECT_WAIT_TIME_MS ) )
     {
         // Stop the drain pump and the RO pump to exit the closed loop
@@ -2110,4 +2117,25 @@
     }
 }
 
+/*********************************************************************//**
+ * @brief
+ * The writeDisinfectDataToNV function writes the disinfection data to the
+ * non-volatile memory.
+ * @details Inputs: disinfectNVOps
+ * @details Outputs: disinfectNVOps
+ * @return: none
+ *************************************************************************/
+static void writeDisinfectDataToNV( void )
+{
+    if ( FALSE == disinfectNVOps.hasDisCompleteDateBeenWrittenToNV )
+    {
+        disinfectNVOps.hasDisCompleteDateBeenWrittenToNV = setDisinfectStatus( TRUE );
+    }
+
+    if ( FALSE == disinfectNVOps.hasDisStatusBeenWrittenToNV )
+    {
+        disinfectNVOps.hasDisStatusBeenWrittenToNV = setLastDisinfectDate( USAGE_INFO_HEAT_DISINFECT, getRTCTimestamp() );
+    }
+}
+
 /**@}*/