Index: firmware/App/Controllers/PresOccl.c
===================================================================
diff -u -rc1f0ee088a6d3e24a6920470ccda9e000c26dbed -raac87fcc5e595db0659a983017ce5113f1dd295f
--- firmware/App/Controllers/PresOccl.c	(.../PresOccl.c)	(revision c1f0ee088a6d3e24a6920470ccda9e000c26dbed)
+++ firmware/App/Controllers/PresOccl.c	(.../PresOccl.c)	(revision aac87fcc5e595db0659a983017ce5113f1dd295f)
@@ -179,6 +179,7 @@
 static OVERRIDE_F32_T shortFilteredVenousPressure  = { 0.0, 0.0, 0.0, 0 };      ///< Measured venous pressure after short (1 s) filter.
 static BOOL useShortStabilizeTime;                                              ///< Flag to use short stabilize time.
 static BOOL resetFillExemptPeriod;                                              ///< Flag to reset the exempt period after defined time expire.
+static BOOL lowVenousPressureExemptCheck;                                       ///< low venous pressure exempt check flag based on the air trap valve status
 
 static U32 bloodPumpOcclusionAfterCartridgeInstall;                             ///< Measured blood pump occlusion reading taken after cartridge install.
 
@@ -269,6 +270,7 @@
     bloodPumpOcclusionAfterCartridgeInstall         = 0;
     useShortStabilizeTime                           = USE_NORMAL_STABILIZATION_PERIOD;
     resetFillExemptPeriod                           = TRUE;
+    lowVenousPressureExemptCheck                    = TRUE;
 }
 
 /*********************************************************************//**
@@ -832,10 +834,15 @@
     {
         venLowPresExemptAfterAirTrapFillTimerCtr = 0;
         resetFillExemptPeriod = FALSE;
+        lowVenousPressureExemptCheck = FALSE;
     }
     else
     {
-        venLowPresExemptAfterAirTrapFillTimerCtr++;
+        // Increment counter on airtrap valve close state
+        if( TRUE == lowVenousPressureExemptCheck )
+        {
+            venLowPresExemptAfterAirTrapFillTimerCtr++;
+        }
     }
 
 #ifndef _RELEASE_
@@ -1001,6 +1008,25 @@
 
 /*********************************************************************//**
  * @brief
+ * The signalLowVenousPressureCheck function sets the low venous pressure Exempt check flag based on the air trap valve status .
+ * @details Inputs: lowVenousPressureExemptCheck
+ * @details Outputs: lowVenousPressureExemptCheck
+ * @return none.
+ *************************************************************************/
+void signalLowVenousPressureCheck( BOOL enable )
+{
+    if ( TRUE == enable )
+    {
+        lowVenousPressureExemptCheck = TRUE;
+    }
+    else
+    {
+        lowVenousPressureExemptCheck = FALSE;
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The getMeasuredArterialPressure function gets the current arterial pressure.
  * @details Inputs: arterialPressure
  * @details Outputs: none