Index: firmware/App/Modes/ModeDrain.c
===================================================================
diff -u -rf656b17f3d8d93b4fca49c9725e096e7eb55acc7 -r1a5efe97f5f39594b45797fded52cafce92afe80
--- firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision f656b17f3d8d93b4fca49c9725e096e7eb55acc7)
+++ firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision 1a5efe97f5f39594b45797fded52cafce92afe80)
@@ -34,20 +34,27 @@
 // ********** private definitions **********
 
 #define TARGET_DRAIN_PUMP_RPM           2100                                ///< Target drain pump speed (in RPM).
-#define DRAIN_WEIGHT_UNCHANGE_TIMEOUT    ( 15 * MS_PER_SECOND )              ///< Time period of unchanged weight during draining before timeout.
+#define DRAIN_WEIGHT_UNCHANGE_TIMEOUT   ( 2 * MS_PER_SECOND )               ///< Time period of unchanged weight during draining before timeout.
+/// Time period to wait after drain complete and before taring load cells.
+#define DRAIN_EMPTY_TARE_WAIT           ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )
 
 #define TARGET_RO_PRESSURE_PSI          130                                 ///< Target pressure for RO pump.
 #define TARGET_RO_FLOW_RATE_L           0.3                                 ///< Target flow rate for RO pump.
 
+#define DELAY_RES_DRAIN_VALVE_MS        1000                                ///< Delay reservoir drain valve open by 1 second.
+#define DELAY_DRAIN_PUMP_MS             2000                                ///< Delay drain pump on by 2 seconds.
+
 // ********** private data **********
 
-static DG_DRAIN_STATE_T drainState = DG_DRAIN_STATE_START;                  ///< Currently active drain state.
+static DG_DRAIN_STATE_T drainState;                                         ///< Currently active drain state.
+static U32 drainEmptyTareTimerCtr;                                          ///< Timer counter for delay between drain complete and load cell tare.
 
 static U32 tempTrans = 0;
 
 // ********** private function prototypes **********
 
 static DG_DRAIN_STATE_T handleDrainState( void );
+static DG_DRAIN_STATE_T handleTareState( void );
 
 /*********************************************************************//**
  * @brief
@@ -59,6 +66,7 @@
 void initDrainMode( void )
 {
     drainState = DG_DRAIN_STATE_START;
+    drainEmptyTareTimerCtr = 0;
 }
 
 /*********************************************************************//**
@@ -73,30 +81,22 @@
     // re-initialize each time we transition to drain mode
     initDrainMode();
 
-/*#ifndef V_2_SYSTEM
+#ifndef V_2_SYSTEM
     DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
 
     if ( DG_RESERVOIR_1 == inactiveReservoir )
     {
-        setValveState( VRD1, VALVE_STATE_OPEN );
+        setValveStateDelayed( VRD1, VALVE_STATE_OPEN, DELAY_RES_DRAIN_VALVE_MS );
     }
     else if ( DG_RESERVOIR_2 == inactiveReservoir )
     {
-        setValveState( VRD2, VALVE_STATE_OPEN );
+        setValveStateDelayed( VRD2, VALVE_STATE_OPEN, DELAY_RES_DRAIN_VALVE_MS );
     }
-#endif*/
-
-    // TODO test code remove
-    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
-    tempTrans = 0;
+#endif
+    // set initial actuator states
     setValveState( VDR, VALVE_STATE_DRAIN_C_TO_NO );
-    // TODO test code remove
+    setDrainPumpTargetRPMDelayed( TARGET_DRAIN_PUMP_RPM, DELAY_DRAIN_PUMP_MS );
 
-    // set initial actuator states
-    //setValveState( VDR, VALVE_STATE_DRAIN_C_TO_NO ); TODO uncomment
-
-    //setDrainPumpTargetRPM( TARGET_DRAIN_PUMP_RPM ); //TODO comment this for testing
-
     // NOTE: The target flow rate should be set prior to setting the start primary heater
     // because the initial guess in the heaters driver needs the target flow to calculate
     // the new PWMs for the main and small primary heaters
@@ -123,13 +123,20 @@
     switch ( drainState )
     {
         case DG_DRAIN_STATE_START:
-            drainState = DG_DRAIN_STATE_DRAIN;
+            if ( TRUE == isDrainPumpOn() )
+            {
+                drainState = DG_DRAIN_STATE_DRAIN;
+            }
             break;
 
         case DG_DRAIN_STATE_DRAIN:
             drainState = handleDrainState();
             break;
 
+        case DG_DRAIN_STATE_TARE:
+            drainState = handleTareState();
+            break;
+
         default:
             SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_DRAIN_MODE_INVALID_EXEC_STATE, drainState )
             drainState = DG_DRAIN_STATE_START;
@@ -141,9 +148,10 @@
 
 /*********************************************************************//**
  * @brief
- * The handleDrainState function handles the drain state  of the drain mode state machine.
+ * The handleDrainState function handles the drain state of the drain mode
+ * state machine.
  * @details Inputs: none
- * @details Outputs: Drain out from reservoir
+ * @details Outputs: none
  * @return the next state
  *************************************************************************/
 static DG_DRAIN_STATE_T handleDrainState( void )
@@ -174,6 +182,48 @@
     if ( TRUE == hasTargetDrainVolumeBeenReached( inactiveReservoir, DRAIN_WEIGHT_UNCHANGE_TIMEOUT ) )
     {
         setDrainPumpTargetRPM( 0 );
+
+#ifndef V_2_SYSTEM
+        if ( DG_RESERVOIR_1 == inactiveReservoir )
+        {
+            setValveState( VRD1, VALVE_STATE_CLOSED );
+        }
+        else if ( DG_RESERVOIR_2 == inactiveReservoir )
+        {
+            setValveState( VRD2, VALVE_STATE_CLOSED );
+        }
+#endif
+
+        if ( TRUE == isReservoirTarePending() )
+        {   // Tare reservoir load cells at empty if requested
+            result = DG_DRAIN_STATE_TARE;
+        }
+        else
+        {
+            requestNewOperationMode( DG_MODE_CIRC );
+        }
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handleTareState function handles the tare state of the drain mode
+ * state machine.
+ * @details Inputs: drainEmptyTareTimerCtr
+ * @details Outputs: drainEmptyTareTimerCtr
+ * @return the next state
+ *************************************************************************/
+static DG_DRAIN_STATE_T handleTareState( void )
+{
+    DG_DRAIN_STATE_T result = DG_DRAIN_STATE_TARE;
+    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
+
+    if ( ++drainEmptyTareTimerCtr > DRAIN_EMPTY_TARE_WAIT )
+    {
+        drainEmptyTareTimerCtr = 0;
+        tareLoadCellsAtEmpty( inactiveReservoir );
         requestNewOperationMode( DG_MODE_CIRC );
 
 #ifndef V_2_SYSTEM