Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r8373758a03ea82b46b4b313d2f2b24e3974a17f6 -r0a4dcd288d4347b85baaa0b07da568b6add5eac7
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 8373758a03ea82b46b4b313d2f2b24e3974a17f6)
+++ firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 0a4dcd288d4347b85baaa0b07da568b6add5eac7)
@@ -1,14 +1,14 @@
 /**************************************************************************
 *
-* Copyright (c) 2020-2022 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2020-2023 Diality Inc. - All Rights Reserved.
 *
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * @file    AirTrap.c
 *
-* @author  (last)      Darren Cox
-* @date    (last)      10-Mar-2022
+* @author  (last)      Dara Navaei
+* @date    (last)      13-Dec-2022
 *
 * @author  (original)  Sean Nash
 * @date    (original)  16-Sep-2020
@@ -33,9 +33,11 @@
 // ********** private definitions **********
 
 /// Interval (ms/task time) at which the air trap data is published on the CAN bus.
-#define AIR_TRAP_DATA_PUB_INTERVAL          ( MS_PER_SECOND / TASK_PRIORITY_INTERVAL )
+#define AIR_TRAP_DATA_PUB_INTERVAL          ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )
 /// Persistence period for illegal level sensors fault.
 static const U32 AIR_TRAP_ILLEGAL_LEVELS_PERSISTENCE = ( MS_PER_SECOND * 2 / TASK_PRIORITY_INTERVAL );
+static const U32 AIR_TRAP_UPPER_LEVEL_PERSISTENCE = ( MS_PER_SECOND * 2 / TASK_PRIORITY_INTERVAL );
+
 /// Volume (in mL) of venous portion of blood circuit line.  TODO - get actual volume from Systems.
 #define VENOUS_LINE_VOLUME_ML               ( 200.0F )
 #define DATA_PUBLISH_COUNTER_START_COUNT    7                                                      ///< Data publish counter start count.
@@ -64,6 +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 **********
@@ -178,6 +181,27 @@
     airTrapLevels[ AIR_TRAP_LEVEL_SENSOR_LOWER ].data = (U32)( TRUE == lower ? AIR_TRAP_LEVEL_AIR : AIR_TRAP_LEVEL_FLUID );
     airTrapLevels[ AIR_TRAP_LEVEL_SENSOR_UPPER ].data = (U32)( TRUE == upper ? AIR_TRAP_LEVEL_AIR : AIR_TRAP_LEVEL_FLUID );
 
+    if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) &&
+         MODE_TREA == getCurrentOperationMode() )
+    {
+        if ( ++airTrapUpperLevelCtr >= AIR_TRAP_UPPER_LEVEL_PERSISTENCE )
+        {
+#ifndef _RELEASE_
+            if ( getSoftwareConfigStatus( SW_CONFIG_DISABLE_ILLEGAL_AIR_TRAP_ALARM ) != SW_CONFIG_ENABLE_VALUE )
+#endif
+            {
+                activateAlarmNoData( ALARM_ID_HD_AIR_TRAP_OVERFILL );
+            }
+        }
+    }
+    else
+    {
+        if ( airTrapUpperLevelCtr > 0 )
+        {
+            airTrapUpperLevelCtr = 0;
+        }
+    }
+
     // Check level readings are valid
     if ( ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) &&
          ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) ) )
@@ -347,7 +371,7 @@
         result = AIR_TRAP_MANUAL_CONTROL_STATE;
     }
     // Transition to closed valve state when fluid detected at upper level
-    else if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_UPPER ) )
+    else if ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) )
     {
         setValveAirTrap( STATE_CLOSED );
         result = AIR_TRAP_VALVE_CLOSED_STATE;