Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r3ee7155720dd102ca0dc22102246285728d6068d -r7b9f88168b56fecff1a4e1ccdbd494c1a1b28fff
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 3ee7155720dd102ca0dc22102246285728d6068d)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 7b9f88168b56fecff1a4e1ccdbd494c1a1b28fff)
@@ -66,6 +66,7 @@
 
 static U32  fillStartTime = 0;                                                              ///< Time stamp for start of air trap fill.
 
+static U32 airTrapUpperLevelCtr = 0;                                                        ///< Timer count for upper level persistence.
 static U32  airTrapIllegalLevelSensorsCtr = 0;                                              ///< Timer counter for illegal level sensor fault.
 
 // ********** private function prototypes **********
@@ -183,7 +184,7 @@
     if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) &&
          MODE_TREA == getCurrentOperationMode() )
     {
-        if ( ++airTrapIllegalLevelSensorsCtr >= AIR_TRAP_UPPER_LEVEL_PERSISTENCE )
+        if ( ++airTrapUpperLevelCtr >= AIR_TRAP_UPPER_LEVEL_PERSISTENCE )
         {
 #ifndef _RELEASE_
             if ( getSoftwareConfigStatus( SW_CONFIG_DISABLE_ILLEGAL_AIR_TRAP_ALARM ) != SW_CONFIG_ENABLE_VALUE )
@@ -193,6 +194,13 @@
             }
         }
     }
+    else
+    {
+        if ( airTrapUpperLevelCtr > 0 )
+        {
+            airTrapUpperLevelCtr--;
+        }
+    }
 
     // Check level readings are valid
     if ( ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) &&
Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -rb030ab45b224005353368b098ff7d30bc0bb8405 -r7b9f88168b56fecff1a4e1ccdbd494c1a1b28fff
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision b030ab45b224005353368b098ff7d30bc0bb8405)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 7b9f88168b56fecff1a4e1ccdbd494c1a1b28fff)
@@ -514,18 +514,6 @@
         SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_PRIME_SALINE_PURGE_AIR_TIME_OUT, PURGE_AIR_TIME_OUT_COUNT );
     }
 
-    if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) )
-    {
-        if ( FALSE == primeFirstPurgePass )
-        {
-            setBloodPumpTargetFlowRate( BLOOD_PUMP_FAST_FLOW_RATE_PURGE_AIR_ML_MIN, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
-        }
-        else
-        {
-            setBloodPumpTargetFlowRate( BLOOD_PUMP_SLOW_FLOW_RATE_PURGE_AIR_ML_MIN, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
-        }
-    }
-
     if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) )
     {
         setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
@@ -753,7 +741,7 @@
     {
         state = HD_PRIME_RESERVOIR_TWO_FILL_COMPLETE_STATE;
     }
-
+    // TODO: Rework alarm and timeout logic here. PRIME_SALINE_DIALYZER_TIME_OUT_COUNT may not be reached.
     if ( TRUE == didTimeout( primeSalineDialyzerStartTime, PRIME_SALINE_DIALYZER_TIME_OUT_COUNT ) )
     {
         SET_ALARM_WITH_1_U32_DATA( ALARM_ID_PRIME_SALINE_DIALYZER_TIME_OUT, PRIME_SALINE_DIALYZER_TIME_OUT_COUNT );  // Trigger HD prime saline dialyzer time out alarm.