Index: firmware/App/Controllers/AirTrap.c
===================================================================
diff -u -r405d46b9b75630e35f003c42647d85c83d166b62 -r0a4dcd288d4347b85baaa0b07da568b6add5eac7
--- firmware/App/Controllers/AirTrap.c	(.../AirTrap.c)	(revision 405d46b9b75630e35f003c42647d85c83d166b62)
+++ 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)      Dara Navaei
-* @date    (last)      04-Jan-2022
+* @date    (last)      13-Dec-2022
 *
 * @author  (original)  Sean Nash
 * @date    (original)  16-Sep-2020
@@ -33,28 +33,30 @@
 // ********** 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               ( 200.0 )
-#define DATA_PUBLISH_COUNTER_START_COUNT    7                                                      ///< Data publish counter start count.
-
-/// Defined states for the air trap controller state machine.
-typedef enum AirTrap_States
-{
-    AIR_TRAP_INIT_STATE = 0,                ///< Initialization state
+#define VENOUS_LINE_VOLUME_ML               ( 200.0F )
+#define DATA_PUBLISH_COUNTER_START_COUNT    7                                                      ///< Data publish counter start count.
+
+/// Defined states for the air trap controller state machine.
+typedef enum AirTrap_States
+{
+    AIR_TRAP_INIT_STATE = 0,                ///< Initialization state
     AIR_TRAP_MANUAL_CONTROL_STATE,          ///< Manually control air trap valve state
     AIR_TRAP_VALVE_CLOSED_STATE,            ///< Valve closed state - until air detected at lower level
-    AIR_TRAP_VALVE_OPEN_STATE,              ///< Valve open state - until fluid detected at upper level
-    NUM_OF_AIR_TRAP_STATES                  ///< Number of air trap controller states
-} AIR_TRAP_STATE_T;
-
-// ********** private data **********
-
-static AIR_TRAP_STATE_T airTrapControllerState;                                             ///< Current state of air trap controller state machine.
-static U32 airTrapDataPublicationTimerCounter;                                              ///< Used to schedule air trap data publication to CAN bus.
+    AIR_TRAP_VALVE_OPEN_STATE,              ///< Valve open state - until fluid detected at upper level
+    NUM_OF_AIR_TRAP_STATES                  ///< Number of air trap controller states
+} AIR_TRAP_STATE_T;
 
+// ********** private data **********
+
+static AIR_TRAP_STATE_T airTrapControllerState;                                             ///< Current state of air trap controller state machine.
+static U32 airTrapDataPublicationTimerCounter;                                              ///< Used to schedule air trap data publication to CAN bus.
+
 /// Interval (in ms) at which to publish air trap data to CAN bus.
 static OVERRIDE_U32_T airTrapDataPublishInterval = { AIR_TRAP_DATA_PUB_INTERVAL, AIR_TRAP_DATA_PUB_INTERVAL, 0, 0 };
 static OVERRIDE_U32_T airTrapLevels[ NUM_OF_AIR_TRAP_LEVEL_SENSORS ];                       ///< Detected air trap level for each level sensor.
@@ -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 ) ) )
@@ -220,7 +244,9 @@
 
         if ( TRUE == didTimeout( fillStartTime, fillTimeoutMS ) )
         {
+#ifndef _RELEASE_
             if ( getSoftwareConfigStatus( SW_CONFIG_DISABLE_AIR_TRAP_LEVELING_ALARM ) != SW_CONFIG_ENABLE_VALUE )
+#endif
             {
                 activateAlarmNoData( ALARM_ID_AIR_TRAP_FILL_DURING_TREATMENT );
             }
@@ -345,7 +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;