Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r0563950b76967db544ca2d17fe2b1008ca13b41b -rf41cae1e5c4dae0a89e5987f95ebb04b773b6b6b
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 0563950b76967db544ca2d17fe2b1008ca13b41b)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision f41cae1e5c4dae0a89e5987f95ebb04b773b6b6b)
@@ -37,9 +37,9 @@
 
 
 #define AIR_TRAP_DATA_PUB_INTERVAL          ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )           ///< Interval (ms/task time) at which the air trap data is published on the CAN bus.
-#define AIR_TRAP_FILL_TIMEOUT_MS            ( 6 * MS_PER_SECOND )                               ///< Air trap fill timeout period (in ms).
+#define AIR_TRAP_FILL_TIMEOUT_MS            ( 10 * MS_PER_SECOND )                              ///< Air trap fill timeout period (in ms).
 #define AIR_PUMP_ON_DELAY_TIME_MS           ( 10 * MS_PER_SECOND )                              ///< Delay between air pump On (in ms).
-#define AIR_PUMP_UPPER_LEVEL_PERSISTENCE    ( 300 / TASK_GENERAL_INTERVAL )                     ///< Persistence time for air pump operation after air trap upper level reads air.
+#define AIR_PUMP_ON_STOP_TIME_MIN_MS        200                                                 ///< Stop air Pump time.
 #define AIR_PUMP_ON_ERROR_MAX_CNT           6                                                   ///< Maximum number of air pump on events within time window before alarm triggered. Do not exceed MAX_TIME_WINDOWED_COUNT.
 #define AIR_PUMP_ON_ERROR_TIME_WIN_MS       ( 60 * MS_PER_SECOND )                              ///< Time window for Air Pump on count error.
 #define AIR_TRAP_LEVEL_DEBOUNCE_TIME_MS     ( 400 )                                             ///< Air trap level sensor debounce time
@@ -76,8 +76,11 @@
 
 static U32  fillStartTime = 0;                                                              ///< Time stamp for start of air trap fill.
 static U32  airPumpOnDelayStartTime = 0;                                                    ///< Air pump On start time.
+static U32  stopAirPumpStartTime = 0;                                                       ///< Stop air pump start time.
+// Air pump on delay after fill adjustment
+static const U32 AIR_PUMP_ON_DELAY_ADJUST_AFTER_FILL = ( AIR_PUMP_ON_DELAY_TIME_MS - ( 1 * MS_PER_SECOND ) );
 
-static U32 airPumpUpperLevelCtr = 0;                                                        ///< Timer count for air pump persistence.
+static BOOL airTrapValveOpenAtStartOfTreatement = FALSE;                                    ///< To Keep the fluid level high close to Air trap upper level during start of treatment
 
 // ********** private function prototypes **********
 
@@ -98,9 +101,10 @@
     U32 i;
 
     resetAirTrap();
-    airTrapDataPublicationTimerCounter = DATA_PUBLISH_COUNTER_START_COUNT;
-    airPumpUpperLevelCtr               = 0;
-    airPumpOnDelayStartTime            = getMSTimerCount();
+    airTrapDataPublicationTimerCounter      = DATA_PUBLISH_COUNTER_START_COUNT;
+    airTrapValveOpenAtStartOfTreatement     = TRUE;
+    airPumpOnDelayStartTime                 = getMSTimerCount();
+    stopAirPumpStartTime                    = 0;
 
     for ( i = 0; i < NUM_OF_AIR_TRAP_LEVEL_SENSORS; i++ )
     {
@@ -356,6 +360,11 @@
 {
     AIR_TRAP_STATE_T result = AIR_TRAP_VALVE_CLOSED_STATE;
 
+    // Air pump stop time based on the blood flow rate
+    S32  qB                 = abs( getTargetBloodFlowRate() );
+    U32  qBx                = ( 0 == qB ? MIN_SET_BLOOD_FLOW_RATE : (U32)qB );
+    U32  airPumpStopTime    = AIR_PUMP_ON_STOP_TIME_MIN_MS + ( ( qBx - MIN_SET_BLOOD_FLOW_RATE ) / 2 );
+
     // Transition to manual valve control state when requested
     if ( TRUE == pendingStopAirTrapController )
     {
@@ -365,40 +374,50 @@
         if ( AIR_PUMP_STATE_ON == getAirPumpState() )
         {
             setAirPumpState( AIR_PUMP_STATE_OFF );
-            airPumpUpperLevelCtr = 0;
         }
     }
 
+    //Open valve once at start of treatment ( blood priming)
+    else if ( TRUE == airTrapValveOpenAtStartOfTreatement )
+    {
+        airTrapValveOpenAtStartOfTreatement = FALSE;
+        if ( AIR_PUMP_STATE_ON == getAirPumpState() )
+        {
+            setAirPumpState( AIR_PUMP_STATE_OFF );
+        }
+
+        setValveAirTrap( STATE_OPEN );
+        fillStartTime = getMSTimerCount();
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, STATE_OPEN, 0 );
+        result = AIR_TRAP_VALVE_OPEN_STATE;
+    }
+
+    // Turn air pump off after defined time or air detected at upper level
+    else if ( ( AIR_PUMP_STATE_ON == getAirPumpState() ) &&
+              ( ( TRUE == didTimeout( stopAirPumpStartTime, airPumpStopTime ) ) ||
+                ( ( AIR_TRAP_LEVEL_AIR   == getRawAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) ) &&
+                  ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) ) ) )
+
+    {
+        setAirPumpState( AIR_PUMP_STATE_OFF );
+        airPumpOnDelayStartTime = getMSTimerCount();
+    }
+
     //Turn on air pump if fluid reaches upper level.
     else if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) )
     {
         if ( ( AIR_PUMP_STATE_OFF == getAirPumpState() ) &&
              ( TRUE == didTimeout( airPumpOnDelayStartTime, AIR_PUMP_ON_DELAY_TIME_MS ) ) )
         {
             setAirPumpState( AIR_PUMP_STATE_ON );
-            airPumpUpperLevelCtr = 0;
+            stopAirPumpStartTime = getMSTimerCount();
             signalInitiatePressureStabilization( USE_SHORT_STABILIZATION_PERIOD );
         }
     }
 
-    else if ( ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) ) &&
-              ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) )
-    {
-        if ( AIR_PUMP_STATE_ON == getAirPumpState() )
-        {
-            airPumpUpperLevelCtr++;
-            // Turn air pump off once we detect air at upper level and exceed persistence
-            if ( airPumpUpperLevelCtr >= AIR_PUMP_UPPER_LEVEL_PERSISTENCE )
-            {
-                setAirPumpState( AIR_PUMP_STATE_OFF );
-                airPumpOnDelayStartTime = getMSTimerCount();
-            }
-        }
-    }
-
     // Transition to open valve state when air detected at lower level
     else if ( ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) ) &&
-            ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) )
+              ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) )
     {
         if ( AIR_PUMP_STATE_ON == getAirPumpState() )
         {
@@ -407,7 +426,7 @@
 
         setValveAirTrap( STATE_OPEN );
         fillStartTime = getMSTimerCount();
-        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, STATE_OPEN, 0 );
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, 0, 0 );
         result = AIR_TRAP_VALVE_OPEN_STATE;
     }