Index: firmware/App/Modes/ModePostTreat.c
===================================================================
diff -u -raa7b1f5f68aae23c1c52b32658fcb625c29accfb -r269317d07ab6ccbff5294953d2ecc1cbc43336ab
--- firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision aa7b1f5f68aae23c1c52b32658fcb625c29accfb)
+++ firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision 269317d07ab6ccbff5294953d2ecc1cbc43336ab)
@@ -62,6 +62,7 @@
 static BOOL disposableRemovalConfirmed;                             ///< Flag indicates user confirms disposable removal.
 static BOOL rinseConcentrateLines;                                  ///< FLag indicates to rinse concentrate lines.
 static BOOL isThisFirstDrain;                                       ///< Flag to indicate whether this is the first time the reservoir is drained.
+static BOOL dgCommandSent;                                          ///< Flag indicates whether a DG command has been already sent.
 static HD_POST_TREATMENT_STATE_T currentPostTreatmentState;         ///< Current state of post-treatment mode state machine.
 static DRAIN_STATE_T currentDrainReservoirState;                    ///< Current drain reservoir state.
 static U32 postTreatmentPublishTimerCounter;                        ///< Timer counter used to schedule post-treatment data broadcast.
@@ -88,7 +89,8 @@
  * @details Inputs: none
  * @details Outputs: patientDisconnectionConfirmed, disposableRemovalConfirmed,
  * rinseConcentrateLines, isThisFirstDrain, currentPostTreatmentState,
- * currentDrainReservoirState, postTreatmentPublishTimerCounter, treatmentLogData
+ * currentDrainReservoirState, postTreatmentPublishTimerCounter, treatmentLogData,
+ * dgCommandSent
  * @return none
  *************************************************************************/
 void initPostTreatmentMode( void )
@@ -97,6 +99,7 @@
     disposableRemovalConfirmed       = FALSE;
     rinseConcentrateLines            = FALSE;
     isThisFirstDrain                 = TRUE;
+    dgCommandSent                    = FALSE;
     currentPostTreatmentState        = HD_POST_TREATMENT_DRAIN_RESERVOIRS_STATE;
     currentDrainReservoirState       = DRAIN_RESERVOIR_SWITCH_STATE;
     postTreatmentPublishTimerCounter = 0;
@@ -528,8 +531,8 @@
  * @brief
  * The handleDrainReservoirSwitchState function waits for DG to complete
  * reservoir switch.
- * @details Inputs: isThisFirstDrain
- * @details Outputs: rinseConcentrateLines
+ * @details Inputs: isThisFirstDrain, dgCommandSent
+ * @details Outputs: rinseConcentrateLines, dgCommandSent
  * @return next state
  *************************************************************************/
 static DRAIN_STATE_T handleDrainReservoirSwitchState( void )
@@ -538,20 +541,36 @@
 
     if ( ( DG_MODE_GENE == getDGOpMode() ) && ( DG_GEN_IDLE_MODE_STATE_FLUSH_WATER == getDGSubMode() ) )
     {
-        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+        DG_CMD_RESPONSE_T dgCmdResp;
 
-        // The first drain starts with setting the reservoir 2 as active and then the first reservoir is drained
-        rsrvrCmd.reservoirID            = (U32)( TRUE == isThisFirstDrain ? DG_RESERVOIR_2 : DG_RESERVOIR_1 );
-        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+        if ( FALSE == dgCommandSent )
+        {
+            DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
-        cmdSetDGActiveReservoir( &rsrvrCmd );
+            // The first drain starts with setting the reservoir 2 as active and then the first reservoir is drained
+            rsrvrCmd.reservoirID            = (U32)( TRUE == isThisFirstDrain ? DG_RESERVOIR_2 : DG_RESERVOIR_1 );
+            rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+            dgCommandSent                   = TRUE;
 
-        if ( TRUE == hasDGCompletedReservoirSwitch() )
+            cmdSetDGActiveReservoir( &rsrvrCmd );
+        }
+        else if ( TRUE == getDGCommandResponse( DG_CMD_SWITCH_RESERVOIR, &dgCmdResp ) )
         {
-            // Check if the reservoir switch has been completed
-            // If this is the first drain, rinse the concentrate lines too
-            rinseConcentrateLines = ( TRUE == isThisFirstDrain ? TRUE : FALSE );
-            state                 = DRAIN_RESERVOIR_START_DRAIN_STATE;
+            if ( DG_CMD_REQUEST_REJECT_REASON_NONE == dgCmdResp.rejectCode )
+            {
+                if ( TRUE == hasDGCompletedReservoirSwitch() )
+                {
+                    // Check if the reservoir switch has been completed
+                    // If this is the first drain, rinse the concentrate lines too
+                    rinseConcentrateLines = ( TRUE == isThisFirstDrain ? TRUE : FALSE );
+                    dgCommandSent         = FALSE;
+                    state                 = DRAIN_RESERVOIR_START_DRAIN_STATE;
+                }
+            }
+            else
+            {
+                dgCommandSent = FALSE;
+            }
         }
     }
 
@@ -562,8 +581,8 @@
  * @brief
  * The handleDrainReservoirStartDrainState function sends command to DG to
  * send the drain command to DG.
- * @details Inputs: rinseConcentrateLines
- * @details Outputs: none
+ * @details Inputs: rinseConcentrateLines, dgCommandSent
+ * @details Outputs: dgCommandSent
  * @return next state
  *************************************************************************/
 static DRAIN_STATE_T handleDrainReservoirStartDrainState( void )
@@ -575,16 +594,28 @@
         DG_CMD_RESPONSE_T dgCmdResp;
 
         // If DG is still in the Idle mode in the flush water state and the drain command has not been sent, send the drain command
-        if ( FALSE == getDGCommandResponse( DG_CMD_START_DRAIN, &dgCmdResp ) )
+        if ( FALSE == dgCommandSent )
         {
             cmdStartDGDrain( DRAIN_RESERVOIR_TO_VOLUME_ML, TRUE, rinseConcentrateLines, TRUE );
+            dgCommandSent = TRUE;
         }
+        else if ( TRUE == getDGCommandResponse( DG_CMD_START_DRAIN, &dgCmdResp ) )
+        {
+            if ( DG_CMD_REQUEST_REJECT_REASON_NONE == dgCmdResp.rejectCode )
+            {
+                if ( DG_MODE_DRAI == getDGOpMode() )
+                {
+                    // If the drain has started, transition to drain state
+                    dgCommandSent = FALSE;
+                    state         = DRAIN_RESERVOIR_DRAIN_STATE;
+                }
+            }
+            else
+            {
+                dgCommandSent = FALSE;
+            }
+        }
     }
-    else if ( DG_MODE_DRAI == getDGOpMode() )
-    {
-        // If the drain has started, transition to drain state
-        state = DRAIN_RESERVOIR_DRAIN_STATE;
-    }
 
     return state;
 }