Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -r55425a4c5370a6fa1faad61dc24fcd76b854d3ed -r6145c5d1a645646587fb077df3c61eef2354f744
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 55425a4c5370a6fa1faad61dc24fcd76b854d3ed)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 6145c5d1a645646587fb077df3c61eef2354f744)
@@ -160,6 +160,54 @@
 
     sendCommandResponseMsg( &cmdResponse );
 }
+
+/*********************************************************************//**
+ * @brief
+ * The changeValveSettingCmd function changes valve settings according to
+ * the given setting ID.
+ * @details Inputs: none
+ * @details Outputs: Specified valve settings has been setup.
+ * @param valveSettingID ID of valve setting to change valves to
+ * @return none
+ *************************************************************************/
+void changeValveSettingCmd( VALVE_SETTING_ID_T valveSettingID )
+{
+    DG_CMD_RESPONSE_T cmdResponse;
+
+    cmdResponse.commandID = DG_CMD_VALVE_SETTING;
+    cmdResponse.rejected = TRUE;
+    cmdResponse.rejectCode = DG_CMD_REQUEST_REJECT_REASON_NONE;
+
+    // valve setting command only valid in re-circulate mode
+    if ( DG_MODE_CIRC == getCurrentOperationMode() )
+    {
+        switch ( valveSettingID )
+        {
+            case VALVE_SETTING_R1_TO_R2:
+                cmdResponse.rejected = FALSE;
+                setValveState( VRO, VALVE_STATE_R1_C_TO_NO );
+                setValveState( VRI, VALVE_STATE_R2_C_TO_NC );
+                break;
+
+            case VALVE_SETTING_R2_TO_R1:
+                cmdResponse.rejected = FALSE;
+                setValveState( VRO, VALVE_STATE_R2_C_TO_NC );
+                setValveState( VRI, VALVE_STATE_R1_C_TO_NO );
+                break;
+
+            default:
+                // invalid reservoir given - cmd will be NAK'd w/ false result.
+                cmdResponse.rejectCode = DG_CMD_REQUEST_REJECT_REASON_INVALID_PARAMETER;
+                break;
+        }
+    }
+    else
+    {
+        cmdResponse.rejectCode = DG_CMD_REQUEST_REJECT_REASON_INVALID_MODE;
+    }
+
+    sendCommandResponseMsg( &cmdResponse );
+}
 
 /*********************************************************************//**
  * @brief
Index: firmware/App/Services/Reservoirs.h
===================================================================
diff -u -r8059b3b67364c3593091a23266f33186430ffe26 -r6145c5d1a645646587fb077df3c61eef2354f744
--- firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision 8059b3b67364c3593091a23266f33186430ffe26)
+++ firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision 6145c5d1a645646587fb077df3c61eef2354f744)
@@ -38,6 +38,14 @@
     NUM_OF_RESERVOIRS       ///< Number of reservoirs
 } RESERVOIR_ID_T;
 
+/// Enumeration of valve settings.
+typedef enum Valve_Setting
+{
+    VALVE_SETTING_R1_TO_R2 = 0,         ///< Valve setting for displacement from reservoir 1 to reservoir 2
+    VALVE_SETTING_R2_TO_R1,             ///< Valve setting for displacement from reservoir 2 to reservoir 1
+    NUM_OF_VALVE_SETTTINGS              ///< Number of valve settings
+} VALVE_SETTING_ID_T;
+
 #pragma pack(push,1)
 
 /// Drain command data structure.
@@ -61,13 +69,14 @@
 
 void initReservoirs( void );
 void execReservoirs( void );
+
+void setActiveReservoirCmd( RESERVOIR_ID_T resID );                 // handle switch reservoirs command from HD
+void changeValveSettingCmd( VALVE_SETTING_ID_T valveSettingID );    // handle valve setting change command from HD
+void startFillCmd( U32 fillToVolMl );                               // handle fill command from HD
+void stopFillCmd( void );                                           // handle stop fill command from HD
+void startDrainCmd( DRAIN_CMD_T drainCmd );                         // handle drain command from HD
+void stopDrainCmd( void );                                          // handle stop drain command from HD
 
-void setActiveReservoirCmd( RESERVOIR_ID_T resID );    // handle switch reservoirs command from HD
-void startFillCmd( U32 fillToVolMl );                  // handle fill command from HD
-void stopFillCmd( void );                              // handle stop fill command from HD
-void startDrainCmd( DRAIN_CMD_T drainCmd );            // handle drain command from HD
-void stopDrainCmd( void );                             // handle stop drain command from HD
-
 RESERVOIR_ID_T getInactiveReservoir( void );
 BOOL hasTargetFillVolumeBeenReached( RESERVOIR_ID_T reservoirId );
 BOOL hasTargetDrainVolumeBeenReached( RESERVOIR_ID_T reservoirId , U32 timeout );
Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r88f28230d288947ba84840b967e95b32e3deffaa -r6145c5d1a645646587fb077df3c61eef2354f744
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 88f28230d288947ba84840b967e95b32e3deffaa)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 6145c5d1a645646587fb077df3c61eef2354f744)
@@ -1011,6 +1011,10 @@
             handleSwitchReservoirCmd( message );
             break;
 
+        case MSG_ID_DG_CHANGE_VALVE_SETTING_CMD:
+            handleChangeValveSettingCmd( message );
+            break;
+
         case MSG_ID_DG_FILL_CMD:
             handleFillCmd( message );
             break;
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r853d846a60d61d1c6f8987d9cdcfc2bc32913840 -r6145c5d1a645646587fb077df3c61eef2354f744
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 853d846a60d61d1c6f8987d9cdcfc2bc32913840)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 6145c5d1a645646587fb077df3c61eef2354f744)
@@ -937,8 +937,34 @@
     sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_DG_2_HD, result );
 }
 
+
 /*********************************************************************//**
  * @brief
+ * The handleChangeValveSettingCmd function handles a switch reservoirs command
+ * from the HD.
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleChangeValveSettingCmd( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+
+    if ( message->hdr.payloadLen == sizeof( U32 ) )
+    {
+        VALVE_SETTING_ID_T valveSettingID;
+
+        result = TRUE;
+        memcpy( &valveSettingID, message->payload, sizeof( U32 ) );
+        changeValveSettingCmd( valveSettingID );
+    }
+
+    sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_DG_2_HD, result );
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleFillCmd function handles a fill command from the HD.
  * @details Inputs: none
  * @details Outputs: message handled
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -rb549c9d87eb01cf1afee74e9fc1e41b3731bdca4 -r6145c5d1a645646587fb077df3c61eef2354f744
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision b549c9d87eb01cf1afee74e9fc1e41b3731bdca4)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 6145c5d1a645646587fb077df3c61eef2354f744)
@@ -111,13 +111,16 @@
 // MSG_ID_REQUEST_FW_VERSIONS
 void handleFWVersionCmd( MESSAGE_T *message );
 
-// MSG_ID_DG_SWITCH_RESERVOIR
+// MSG_ID_DG_SWITCH_RESERVOIR_CMD
 void handleSwitchReservoirCmd( MESSAGE_T *message );
 
-// MSG_ID_DG_FILL
+// MSG_ID_DG_CHANGE_VALVE_SETTING_CMD
+void handleChangeValveSettingCmd( MESSAGE_T *message );
+
+// MSG_ID_DG_FILL_CMD
 void handleFillCmd( MESSAGE_T *message );
 
-// MSG_ID_DG_DRAIN
+// MSG_ID_DG_DRAIN_CMD
 void handleDrainCmd( MESSAGE_T *message );
 
 // MSG_ID_STARTING_STOPPING_TREATMENT