Index: firmware/App/Modes/TreatmentEnd.c
===================================================================
diff -u -r0bb3fe3f34c02bd19c36aff2b98876e46a2ad177 -r48fda88cb7d8607181efb80f98deaaab1b343a92
--- firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision 0bb3fe3f34c02bd19c36aff2b98876e46a2ad177)
+++ firmware/App/Modes/TreatmentEnd.c	(.../TreatmentEnd.c)	(revision 48fda88cb7d8607181efb80f98deaaab1b343a92)
@@ -54,6 +54,7 @@
 static BOOL txEndRinsebackRequested;                                        ///< Flag indicates user requesting final rinseback.
 static BOOL txEndDrainCmdSent;                                              ///< Flag indicates DG Drain command has been sent.
 static U32  treatmentEndPublishTimerCtr;                                    ///< Timer counter for determining interval for treatment end status to be published.
+static BOOL airTrapFillInProgress;                                          ///< Flag indicates an air trap fill is in progress.
 
 // ********** private function prototypes **********
 
@@ -84,6 +85,7 @@
     treatmentEndPublishTimerCtr = 0;
     txEndDrainCmdSent = FALSE;
     resetTreatmentEndFlags();
+    airTrapFillInProgress = FALSE;  // set to false initially - so keep after call to reset function
 }
 
 /*********************************************************************//**
@@ -98,6 +100,7 @@
     txEndAlarmRinsebackRequested = FALSE;
     txEndAlarmEndTreatmentRequested = FALSE;
     txEndRinsebackRequested = FALSE;
+    airTrapFillInProgress = isAirTrapFillInProgress();
 }
 
 /*********************************************************************//**
@@ -271,18 +274,20 @@
     {
         signalGoToRinseback();
     }
-    // set BP to air trap fill rate if air trap fill has been initiated
-    else if ( TRUE == isAirTrapFillInProgress() )
+    // if an air trap fill has started, set BP rate and VBV state accordingly
+    else if ( ( airTrapFillInProgress != TRUE ) && ( TRUE == isAirTrapFillInProgress() ) )
     {
-        if ( 0 == getTargetBloodFlowRate() )
-        {
-            setBloodPumpTargetFlowRate( AIR_TRAP_FILL_BLOOD_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
-        }
+        // set BP to air trap fill rate if air trap fill has been initiated
+        setBloodPumpTargetFlowRate( AIR_TRAP_FILL_BLOOD_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+        // close VBV for fill
+        setValvePosition( VBV, VALVE_POSITION_C_CLOSE );
     }
     // re-open VBV and restore BP rate after air trap fill
-    else if ( VALVE_POSITION_C_CLOSE == getSetValvePosition( VBV ) )
+    else if ( ( TRUE == airTrapFillInProgress ) && ( isAirTrapFillInProgress() != TRUE ) )
     {
+        // re-open VBV after fill
         setValvePosition( VBV, VALVE_POSITION_B_OPEN );
+        // restore BP to Tx End blood flow rate
         setBloodPumpTargetFlowRate( TX_END_BP_FLOW_RATE_ML_MIN, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
     }