Index: firmware/App/Controllers/DGInterface.c
===================================================================
diff -u -r06dc7b658ce158806edc2c907f9b4462275f7bb9 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 06dc7b658ce158806edc2c907f9b4462275f7bb9)
+++ firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -803,14 +803,16 @@
  * @param resID ID of reservoir to set as active (reservoir for HD to draw from)
  * @return none
  *************************************************************************/
-void cmdSetDGActiveReservoir( DG_RESERVOIR_ID_T resID )
+void cmdSetDGActiveReservoir( DG_SWITCH_RSRVRS_CMD_T *cmd )
 {
+    DG_RESERVOIR_ID_T resID = (DG_RESERVOIR_ID_T)cmd->reservoirID;
+
     if ( resID < NUM_OF_DG_RESERVOIRS )
     {
-        dgActiveReservoirSet = resID;
+        dgActiveReservoirSet                           = resID;
         dgCmdResp[ DG_CMD_SWITCH_RESERVOIR ].commandID = DG_CMD_NONE;
 
-        sendDGSwitchReservoirCommand( (U32)resID );
+        sendDGSwitchReservoirCommand( cmd );
     }
     else
     {
Index: firmware/App/Controllers/DGInterface.h
===================================================================
diff -u -ref6283257df7c1f993d58fb934da57ea3e0a7067 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Controllers/DGInterface.h	(.../DGInterface.h)	(revision ef6283257df7c1f993d58fb934da57ea3e0a7067)
+++ firmware/App/Controllers/DGInterface.h	(.../DGInterface.h)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -162,7 +162,7 @@
 void cmdSetDGDialysateHeatingParams( DG_CMD_DIALYSATE_HEATING_PARAMS_T heatingParams );
 void cmdStartDG( void );
 void cmdStopDG( void );
-void cmdSetDGActiveReservoir( DG_RESERVOIR_ID_T resID );
+void cmdSetDGActiveReservoir( DG_SWITCH_RSRVRS_CMD_T *cmd );
 void cmdChangeDGValveSetting( DG_VALVE_SETTING_ID_T valveSettingID );
 void cmdStartDGFill( U32 fillToVolMl, F32 targetFlowLPM );
 void cmdStopDGFill( void );
Index: firmware/App/Modes/ModePostTreat.c
===================================================================
diff -u -r8b73263b38f449dacc0795c67a7cf6240cb79026 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision 8b73263b38f449dacc0795c67a7cf6240cb79026)
+++ firmware/App/Modes/ModePostTreat.c	(.../ModePostTreat.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -538,10 +538,13 @@
 
     if ( ( DG_MODE_GENE == getDGOpMode() ) && ( DG_GEN_IDLE_MODE_STATE_FLUSH_WATER == getDGSubMode() ) )
     {
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
         // The first drain starts with setting the reservoir 2 as active and then the first reservoir is drained
-        DG_RESERVOIR_ID_T id = ( TRUE == isThisFirstDrain ? DG_RESERVOIR_2 : DG_RESERVOIR_1 );
+        rsrvrCmd.reservoirID            = (U32)( TRUE == isThisFirstDrain ? DG_RESERVOIR_2 : DG_RESERVOIR_1 );
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
 
-        cmdSetDGActiveReservoir( id );
+        cmdSetDGActiveReservoir( &rsrvrCmd );
 
         if ( TRUE == hasDGCompletedReservoirSwitch() )
         {
Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r34d0843fa73e79ba3b085dd4aaa393a1ec126fd4 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 34d0843fa73e79ba3b085dd4aaa393a1ec126fd4)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -925,9 +925,14 @@
 
     if ( TRUE == fillReservoirOneStartRequested )
     {
-        fillReservoirOneStartRequested = FALSE;
-        state = PRE_TREATMENT_RESERVOIR_MGMT_DRAIN_CMD_STATE;
-        cmdSetDGActiveReservoir( DG_RESERVOIR_2 );
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+        rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_2;
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+        fillReservoirOneStartRequested  = FALSE;
+        state                           = PRE_TREATMENT_RESERVOIR_MGMT_DRAIN_CMD_STATE;
+
+        cmdSetDGActiveReservoir( &rsrvrCmd );
     }
 
     return state;
@@ -1142,14 +1147,24 @@
                 else
 #endif
                 {
+                    DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+                    rsrvrCmd.reservoirID                     = (U32)DG_RESERVOIR_1;
+                    rsrvrCmd.useLastTrimmerHeaterDC          = FALSE;
                     reservoirFlushedStatus[ DG_RESERVOIR_1 ] = TRUE;
-                    cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
+
+                    cmdSetDGActiveReservoir( &rsrvrCmd );
                 }
             }
             else
             {
+                DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+                rsrvrCmd.reservoirID                     = (U32)DG_RESERVOIR_2;
+                rsrvrCmd.useLastTrimmerHeaterDC          = FALSE;
                 reservoirFlushedStatus[ DG_RESERVOIR_2 ] = TRUE;
-                cmdSetDGActiveReservoir( DG_RESERVOIR_2 );
+
+                cmdSetDGActiveReservoir( &rsrvrCmd );
             }
         }
     }
Index: firmware/App/Modes/PreTreatmentRecirc.c
===================================================================
diff -u -r34d0843fa73e79ba3b085dd4aaa393a1ec126fd4 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision 34d0843fa73e79ba3b085dd4aaa393a1ec126fd4)
+++ firmware/App/Modes/PreTreatmentRecirc.c	(.../PreTreatmentRecirc.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -154,14 +154,19 @@
  *************************************************************************/
 static void setupPreTreatmentRecirculate( void )
 {
+    DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+    rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_1;
+    rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
     doorClosedRequired( TRUE, TRUE );
 
     setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
     setValvePosition( VDO, VALVE_POSITION_C_CLOSE );
     setValvePosition( VBA, VALVE_POSITION_B_OPEN );
     setValvePosition( VBV, VALVE_POSITION_B_OPEN );
     setValveAirTrap( STATE_CLOSED );
-    cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
+    cmdSetDGActiveReservoir( &rsrvrCmd );
     cmdStartDGTrimmerHeater();
     startAirTrapControl();
 
Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r34d0843fa73e79ba3b085dd4aaa393a1ec126fd4 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 34d0843fa73e79ba3b085dd4aaa393a1ec126fd4)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -589,8 +589,13 @@
 
     if ( TRUE == getReservoirFillStatus( DG_RESERVOIR_1 ) )
     {
-        cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
+        rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_1;
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
+        cmdSetDGActiveReservoir( &rsrvrCmd );
+
         if ( TRUE == hasDGCompletedReservoirSwitch() )
         {
             U32 dialyzerDialysateVolume = getDialyzerDialysateVolume();
@@ -770,8 +775,13 @@
 
     if ( TRUE == getReservoirFillStatus( DG_RESERVOIR_2 ) )
     {
-        cmdSetDGActiveReservoir( DG_RESERVOIR_2 );
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
+        rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_1;
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
+        cmdSetDGActiveReservoir( &rsrvrCmd );
+
         if ( TRUE == hasDGCompletedReservoirSwitch() )
         {
             signalBloodPumpHardStop();
Index: firmware/App/Modes/TreatmentEnd.c
===================================================================
diff -u -r8b73263b38f449dacc0795c67a7cf6240cb79026 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision 8b73263b38f449dacc0795c67a7cf6240cb79026)
+++ firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -220,7 +220,12 @@
     {
         if ( getDGInactiveReservoir() != DG_RESERVOIR_1 )
         {
-            cmdSetDGActiveReservoir( DG_RESERVOIR_2 );
+            DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
+
+            rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_2;
+            rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
+            cmdSetDGActiveReservoir( &rsrvrCmd );
         }
         else
         {
Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -r9d81efee3ea73c452bb6b84501c8accf85ab81f7 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 9d81efee3ea73c452bb6b84501c8accf85ab81f7)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -606,16 +606,20 @@
     if ( ( TRUE == didTimeout( reservoirSwitchStartTimeMS, 15000 /*RESERVOIR_SETTLE_TIME_MS*/ ) ) &&
          ( ( dilutionLevelPct >= MAX_RESERVOIR_DILUTION ) || ( volSpentML >= (F32)FILL_RESERVOIR_TO_VOLUME_ML ) || ( getReservoirWeight( active ) > MAX_RESERVOIR_VOL_BEFORE_SWITCH_ML ) ) )
     {
-        DG_RESERVOIR_ID_T inactiveRes = getDGInactiveReservoir();
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
+        DG_RESERVOIR_ID_T inactiveRes   = getDGInactiveReservoir();
+        rsrvrCmd.reservoirID            = (U32)inactiveRes;
+        rsrvrCmd.useLastTrimmerHeaterDC = TRUE;
+
         // TODO test code remove
         //if ( TRUE == test ) // TODO comment the if statement
         {
             // Signal dialysis sub-mode to capture baseline volume for next reservoir.
             setStartReservoirVolume( inactiveRes );
 
             // Command DG to switch reservoirs
-            cmdSetDGActiveReservoir( inactiveRes );
+            cmdSetDGActiveReservoir( &rsrvrCmd );
 
             // Signal dialysis sub-mode to switch reservoirs
             signalReservoirsSwitched();
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r9d81efee3ea73c452bb6b84501c8accf85ab81f7 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 9d81efee3ea73c452bb6b84501c8accf85ab81f7)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -1429,7 +1429,7 @@
  * @param activeReservoir reservoir ID to set as active
  * @return TRUE if msg successfully queued for transmit, FALSE if not
  *************************************************************************/
-BOOL sendDGSwitchReservoirCommand( U32 activeReservoir )
+BOOL sendDGSwitchReservoirCommand( DG_SWITCH_RSRVRS_CMD_T *cmd )
 {
     BOOL result;
     MESSAGE_T msg;
@@ -1438,9 +1438,9 @@
     // Create a message record
     blankMessage( &msg );
     msg.hdr.msgID = MSG_ID_DG_SWITCH_RESERVOIR_CMD;
-    msg.hdr.payloadLen = sizeof( U32 );
+    msg.hdr.payloadLen = sizeof( DG_SWITCH_RSRVRS_CMD_T );
 
-    memcpy( payloadPtr, &activeReservoir, sizeof( U32 ) );
+    memcpy( payloadPtr, cmd, sizeof( DG_SWITCH_RSRVRS_CMD_T ) );
 
     // Serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
     result = serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_DG, ACK_REQUIRED );
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -re8053e6bdafd0638102e01c4250dfd74c0850ba1 -ref398e685d6cfbdcb8c18fd9319819672c6c9d89
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision e8053e6bdafd0638102e01c4250dfd74c0850ba1)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision ef398e685d6cfbdcb8c18fd9319819672c6c9d89)
@@ -357,7 +357,7 @@
 BOOL sendDialysateHeatingParamsToDG( DG_CMD_DIALYSATE_HEATING_PARAMS_T *params );
 
 // MSG_ID_DG_SWITCH_RESERVOIR_CMD
-BOOL sendDGSwitchReservoirCommand( U32 activeReservoir );
+BOOL sendDGSwitchReservoirCommand( DG_SWITCH_RSRVRS_CMD_T *cmd );
 
 // MSG_ID_DG_CHANGE_VALVE_SETTING_CMD
 BOOL sendDGChangeValveSettingCommand( U32 valveSettingCmd );