Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r2464681e74fad9938b3a3c1c45bd9650939b9134 -rf1bcaa360cd1e5cdee553ca0954a083bf61ec7e6
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 2464681e74fad9938b3a3c1c45bd9650939b9134)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision f1bcaa360cd1e5cdee553ca0954a083bf61ec7e6)
@@ -39,8 +39,7 @@
 #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            ( 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_ON_STOP_TIME_MS            400                                                 ///< Stop air Pump after defined time.
-#define AIR_PUMP_UPPER_LEVEL_PERSISTENCE    ( 100 / 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
@@ -75,11 +74,11 @@
 static BOOL pendingStartAirTrapController = FALSE;                                          ///< Flag indicates an air trap controller start request is pending.
 static BOOL pendingStopAirTrapController = FALSE;                                           ///< Flag indicates an air trap controller stop request is pending.
 
-static U32 airPumpUpperLevelCtr = 0;                                                        ///< Timer count for air pump persistence.
-
 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 BOOL airTrapValveOpenAtStablePressureState = FALSE;                                  ///< Periodic AirTrap fill during pressure stable state, to clear any accumulated bubbles
 
@@ -102,9 +101,8 @@
     U32 i;
 
     resetAirTrap();
-
-    airPumpUpperLevelCtr                    = 0;
     airTrapDataPublicationTimerCounter      = DATA_PUBLISH_COUNTER_START_COUNT;
+    airTrapValveOpenAtStablePressureState   = TRUE;
     airPumpOnDelayStartTime                 = getMSTimerCount();
     airTrapValveOpenAtStablePressureState   = TRUE;
     stopAirPumpStartTime                    = 0;
@@ -376,6 +374,11 @@
 {
     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 )
     {
@@ -385,7 +388,6 @@
         if ( AIR_PUMP_STATE_ON == getAirPumpState() )
         {
             setAirPumpState( AIR_PUMP_STATE_OFF );
-            airPumpUpperLevelCtr = 0;
         }
     }
 
@@ -405,22 +407,14 @@
     }
 
     // Turn air pump off after defined time or air detected at upper level
-    else if ( ( ( AIR_PUMP_STATE_ON == getAirPumpState() ) &&
-                ( TRUE == didTimeout( stopAirPumpStartTime, AIR_PUMP_ON_STOP_TIME_MS ) ) ) ||
-              ( ( AIR_TRAP_LEVEL_AIR   == getRawAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) ) &&
-                ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) ) )
+    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 ) ) ) ) )
 
     {
-        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();
-            }
-        }
+        setAirPumpState( AIR_PUMP_STATE_OFF );
+        airPumpOnDelayStartTime = getMSTimerCount();
     }
 
     //Turn on air pump if fluid reaches upper level.
@@ -431,7 +425,6 @@
         {
             setAirPumpState( AIR_PUMP_STATE_ON );
             stopAirPumpStartTime = getMSTimerCount();
-            airPumpUpperLevelCtr = 0;
             signalInitiatePressureStabilization( USE_SHORT_STABILIZATION_PERIOD );
         }
     }
@@ -478,7 +471,7 @@
         setValveAirTrap( STATE_CLOSED );
         signalLowVenousPressureCheck();
         SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_AIR_TRAP_FILL, STATE_CLOSED, 0 );
-        airPumpOnDelayStartTime = getMSTimerCount();
+        airPumpOnDelayStartTime = u32DiffWithWrap( AIR_PUMP_ON_DELAY_ADJUST_AFTER_FILL, getMSTimerCount() );
         result = AIR_TRAP_VALVE_CLOSED_STATE;
     }
     return result;