Index: firmware/App/Modes/ModeGenDialysate.c
===================================================================
diff -u -re6415d33321e7990c3b5e82b0c8a87c64cc3a2c8 -ra711f7995e555b503ed8c295f98fbe7bb9e5abf5
--- firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision e6415d33321e7990c3b5e82b0c8a87c64cc3a2c8)
+++ firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision a711f7995e555b503ed8c295f98fbe7bb9e5abf5)
@@ -75,6 +75,8 @@
 static OVERRIDE_F32_T targetHydChamberFluidTemp;                                            ///< Target hydraulics chamber fluid temperature.
 static OVERRIDE_U32_T isDialDeliveryInProgress;                                             ///< To indicate dialysate started delivering to dialyzer for treatment (overrideable)
 static OVERRIDE_U32_T isDialysateGoodtoDeliver;                                             ///< Flag indicating whether ready to deliver dialysate or not.
+static BOOL pendingSpentChamberFill;                                                        ///< Flag indicating spent chamber fill process to be initiated.
+static BOOL pendingBicarbChamberFill;                                                       ///< Flag indicating bicarb chamber fill process to be initiated.
 static BOOL pendingStopDDGenDialRequest;                                                    ///< Flag indicating TD has requested DD stop the generate dialysate.
 static U32 genDialysateDataPublicationTimerCounter;                                         ///< Used to schedule generate dialysate data publication to CAN bus.
 static OVERRIDE_U32_T genDialysateDataPublishInterval;                                      ///< Generate dialysate mode data publish interval.
@@ -96,6 +98,7 @@
 static F32 getGenDialysateTargetTemperature( void );
 static void calculateTargetDialysateTemp( void );
 static void checkDialysateTemperature( void );
+static void monitorChamberLevelStatus( void );
 static void publishGenDialysateModeData( void );
 
 /*********************************************************************//**
@@ -128,6 +131,8 @@
     genDialysateDataPublicationTimerCounter     = 0;
     isTreatmentParamUpdated                     = FALSE;
     bicarbFillStartTimeMS                       = 0;
+    pendingSpentChamberFill                     = FALSE;
+    pendingBicarbChamberFill                    = FALSE;
     //Testing
     bypassStateDelayStartTimeMS                 = 0;
     delayBypassStateFlag                        = TRUE;
@@ -201,13 +206,13 @@
             break;
 
         case DD_GEND_DIALYSATE_BYPASS_STATE:
-            //Close all balancing chamber valves
-            valveControlForBCClosedState();
             setValveState( DD_M4_VALV, VALVE_STATE_OPEN );
             setValveState( D14_VALV, VALVE_STATE_OPEN );
             setValveState( D53_VALV, VALVE_STATE_OPEN );   // Drain valve
             setValveState( D35_VALV, VALVE_STATE_CLOSED );  // VDI
             setValveState( D40_VALV, VALVE_STATE_CLOSED );  // VDO
+            setValveState( D47_VALV, VALVE_STATE_CLOSED );  // spent chamber purge valve
+            setValveState( D64_VALV, VALVE_STATE_CLOSED );
             setValveState( D34_VALV, VALVE_STATE_OPEN );    // Bypass valve
 
             // Turn on the primary heater
@@ -231,6 +236,8 @@
 
         case DD_GEND_DIALYSATE_DELIVERY_STATE:
             //Previous state
+            setValveState( D47_VALV, VALVE_STATE_CLOSED );  // spent chamber purge valve
+            setValveState( D64_VALV, VALVE_STATE_CLOSED );
             setValveState( DD_M4_VALV, VALVE_STATE_OPEN );
             setValveState( D14_VALV, VALVE_STATE_OPEN );
             setValveState( D53_VALV, VALVE_STATE_OPEN );   // Drain valve
@@ -253,8 +260,6 @@
             break;
 
         case DD_GEND_SPENT_CHAMBER_FILL_STATE:
-            //Close all balancing chamber valves
-            valveControlForBCClosedState();
             //Set valves and actuators
             setValveState( D35_VALV, VALVE_STATE_CLOSED );  // VDI
             setValveState( D40_VALV, VALVE_STATE_CLOSED );  // VDO
@@ -283,14 +288,12 @@
             break;
 
         case DD_GEND_BICARB_CHAMBER_FILL_STATE:
-            //Close all balancing chamber valves
-            valveControlForBCClosedState();
             requestConcentratePumpOff( D11_PUMP, FALSE );
             requestConcentratePumpOff( D10_PUMP, FALSE );
             requestConcentratePumpOff( D76_PUMP, FALSE );
 
             //Set valves and actuators
-            setValveState( D47_VALV, VALVE_STATE_CLOSED );  // Spent chamber purge valve
+            setValveState( D47_VALV, VALVE_STATE_CLOSED );  // spent chamber purge valve
             setValveState( D35_VALV, VALVE_STATE_CLOSED );  // VDI
             setValveState( D40_VALV, VALVE_STATE_CLOSED );  // VDO
             setValveState( D14_VALV, VALVE_STATE_CLOSED );
@@ -363,6 +366,9 @@
     //Check temperature drift between D30 and D28
     checkDialysateTemperatureSensors();
 
+    //Monitor spent and bicarb chamber level
+    monitorChamberLevelStatus();
+
     //TODO: Transition to post gen dialysate then standby.
     if ( TRUE == pendingStopDDGenDialRequest )
     {
@@ -453,6 +459,30 @@
 
 /*********************************************************************//**
  * @brief
+ * The monitorChamberLevelStatus function checks the spent chamber and bicarb
+ * chamber level status and updates the corrosponding flags.
+ * @details \b Inputs: Spent and bicarb chamber levels.
+ * @details \b Outputs: none
+ * @return none
+ *************************************************************************/
+static void monitorChamberLevelStatus( void )
+{
+    LEVEL_STATE_T spentChamberLevel  = getLevelStatus( D46_LEVL );
+    LEVEL_STATE_T bicarbChamberLevel = getLevelStatus( D63_LEVL );
+
+    if ( LEVEL_STATE_LOW == spentChamberLevel )
+    {
+        pendingSpentChamberFill = TRUE;
+    }
+
+    if ( LEVEL_STATE_LOW == bicarbChamberLevel )
+    {
+        pendingBicarbChamberFill = TRUE;
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The calculateTargetDialysateTemp function calculate the delta temperature
  * required for dialysate temperature to meet the set temperature at dialyzer.
  * @details \b Inputs: Qd and target temperature.
@@ -510,9 +540,8 @@
  *************************************************************************/
 static DD_GEND_MODE_STATE_T handleGenDDialysateBypassState( void )
 {
-    DD_GEND_MODE_STATE_T state       = DD_GEND_DIALYSATE_BYPASS_STATE;
-    LEVEL_STATE_T spentChamberLevel  = getLevelStatus( D46_LEVL );
-    LEVEL_STATE_T bicarbChamberLevel = getLevelStatus( D63_LEVL );
+    DD_GEND_MODE_STATE_T state              = DD_GEND_DIALYSATE_BYPASS_STATE;
+    BOOL balancingChambFillInProgress       = getBalancingChamberFillinProgressStatus();
 
     //Testing
     if ( TRUE == delayBypassStateFlag )
@@ -529,17 +558,19 @@
     }
 
 #ifdef __SPENT_CHAMBER_FILL__
-    if ( LEVEL_STATE_LOW == spentChamberLevel )
+    if ( ( TRUE == pendingSpentChamberFill ) && ( FALSE == balancingChambFillInProgress ) )
     {
         setModeGenDStateTransition( DD_GEND_SPENT_CHAMBER_FILL_STATE );
+        pendingSpentChamberFill = FALSE;
         isDialDeliveryInProgress.data = FALSE;
         state = DD_GEND_SPENT_CHAMBER_FILL_STATE;
     }
 #endif
 #ifdef __BICARB_CHAMBER_FILL__
-    if ( LEVEL_STATE_LOW == bicarbChamberLevel )
+    if ( ( TRUE == pendingBicarbChamberFill ) && ( FALSE == balancingChambFillInProgress ) )
     {
         setModeGenDStateTransition( DD_GEND_BICARB_CHAMBER_FILL_STATE );
+        pendingBicarbChamberFill = FALSE;
         isDialDeliveryInProgress.data = FALSE;
         state = DD_GEND_BICARB_CHAMBER_FILL_STATE;
     }
@@ -579,17 +610,19 @@
         state = DD_GEND_DIALYSATE_BYPASS_STATE;
     }
 #ifdef __SPENT_CHAMBER_FILL__
-    else if ( LEVEL_STATE_LOW == spentChamberLevel )
+    else if ( ( TRUE == pendingSpentChamberFill ) && ( FALSE == balancingChambFillInProgress ) )
     {
         setModeGenDStateTransition( DD_GEND_SPENT_CHAMBER_FILL_STATE );
+        pendingSpentChamberFill = FALSE;
         isDialDeliveryInProgress.data = FALSE;
         state = DD_GEND_SPENT_CHAMBER_FILL_STATE;
     }
 #endif
 #ifdef __BICARB_CHAMBER_FILL__
-    else if ( LEVEL_STATE_LOW == bicarbChamberLevel )
+    else if ( ( TRUE == pendingBicarbChamberFill ) && ( FALSE == balancingChambFillInProgress ) )
     {
         setModeGenDStateTransition( DD_GEND_BICARB_CHAMBER_FILL_STATE );
+        pendingBicarbChamberFill = FALSE;
         isDialDeliveryInProgress.data = FALSE;
         state = DD_GEND_BICARB_CHAMBER_FILL_STATE;
     }