Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -rff9c1ff6639463857772152b9339a237e6722184 -r32763ee524dc476f47ba41ee6c2a8a0c65ebf1e1
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision ff9c1ff6639463857772152b9339a237e6722184)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 32763ee524dc476f47ba41ee6c2a8a0c65ebf1e1)
@@ -92,6 +92,8 @@
 
 static BOOL airTrapHasDetectedFaultMode;                                                          ///< Flag indicates air trap unit has handled transition to fault mode.
 
+static BOOL airTrapFirstLowerEvent;                                                               ///< Flag for first lower event
+
 // ********** private function prototypes **********
 
 static AIR_TRAP_STATE_T handleAirTrapManualControlState( void );
@@ -138,6 +140,7 @@
     airTrapLowerDelayStartTime               = 0;
     airTrapLowerStartTime                    = 0;
     airTrapHasDetectedFaultMode              = FALSE;
+    airTrapFirstLowerEvent                   = FALSE;
 }
 
 /*********************************************************************//**
@@ -404,8 +407,20 @@
              ( TRUE == didTimeout( airTrapLowerDelayStartTime, AIR_PUMP_ON_DELAY_TIME_MS ) ) )
         {
             set3WayValveState( H13_VALV, VALVE_3WAY_COMMON_TO_OPEN_STATE );   // open valve H13 to allow air to be pumped into air trap from atmosphere
-            //airTrapAirPumpLowerPowerLevel.data = getCalculatedAirPumpDutyCycle();
-            setAirPumpState( AIR_PUMP_STATE_ON, getAirPumpLowerPowerLevel() );
+            // if it is first lower event
+            if( TRUE == airTrapFirstLowerEvent )
+            {
+                // use the long filtered H14 venous pressure based duty cycle before AP fill event stored in airTrapAirPumpLowerPowerLevel.data during fill
+                setAirPumpState( AIR_PUMP_STATE_ON, getAirPumpLowerPowerLevel() );
+                airTrapFirstLowerEvent = FALSE;
+            }
+            else
+            {
+                // get long filtered H14 venous pressure before AP lower event for subsequent lower event
+                airTrapAirPumpLowerPowerLevel.data = getCalculatedAirPumpDutyCycle();
+                setAirPumpState( AIR_PUMP_STATE_ON, getAirPumpLowerPowerLevel() );
+            }
+
             airTrapLowerStartTime = getMSTimerCount();
             signalInitiatePressureStabilization( USE_SHORT_STABILIZATION_PERIOD );
             SEND_EVENT_WITH_2_U32_DATA( TD_EVENT_AIR_TRAP_LOWER, ON, 0 );
@@ -417,11 +432,14 @@
     else if ( ( airTrapWasFilledAtStartOfTreatement != TRUE ) ||
               ( AIR_TRAP_LEVEL_AIR == getLevelSensorState( H17_LEVL ) ) )
     {
+        // fill/raise duty cycle is always 60%
         setAirPumpState( AIR_PUMP_STATE_ON, getAirPumpRaisePowerLevel() );
         set3WayValveState( H20_VALV, VALVE_3WAY_COMMON_TO_OPEN_STATE );  // open valve H20 to allow air to be pumped out of air trap to atmosphere
         airTrapFillStartTime = getMSTimerCount();
         SEND_EVENT_WITH_2_U32_DATA( TD_EVENT_AIR_TRAP_FILL, ON, 0 );
-        // get long filtered H14 venous pressure before AP fill event
+        // set flag for first lower event
+        airTrapFirstLowerEvent = TRUE;
+        // get long filtered H14 venous pressure and duty cycle before AP fill event for the first lower event
         airTrapAirPumpLowerPowerLevel.data = getCalculatedAirPumpDutyCycle();
         result = AIR_TRAP_RAISE_LEVEL_STATE;
     }
@@ -455,7 +473,7 @@
     {
         airTrapWasFilledAtStartOfTreatement = TRUE;
         set3WayValveState( H20_VALV, VALVE_3WAY_COMMON_TO_CLOSED_STATE );
-        set3WayValveState( H13_VALV, VALVE_3WAY_COMMON_TO_CLOSED_STATE );   // open valve H13 to allow air to be pumped into air trap from atmosphere
+        set3WayValveState( H13_VALV, VALVE_3WAY_COMMON_TO_CLOSED_STATE );
         //airTrapAirPumpLowerPowerLevel.data = getCalculatedAirPumpDutyCycle();
         setAirPumpState( AIR_PUMP_STATE_OFF, AIR_PUMP_MOTOR_OFF );
         // adjust the air trap lower delay start time after fill complete