Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r736cc5b56cc9c784ab1d8fc8687a73d190c35759 -rd916204a4e6286cd5cfbac7fea9ea15ee69b3000
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 736cc5b56cc9c784ab1d8fc8687a73d190c35759)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision d916204a4e6286cd5cfbac7fea9ea15ee69b3000)
@@ -65,6 +65,7 @@
 #define STEADY_VOLUME_DIALYSATE_PRIME_HISTERESIS_ML         0.3F                                               ///< mL of histeresis for the steady state check that determines when bypass line is primed.
 #define STEADY_VOLUME_BYPASS_PRIME_HISTERESIS_ML            0.3F                                               ///< mL of histeresis for the steady state check that determines when bypass line is primed.
 #define PRESSURE_OFFSET_DIALYSATE_PRIME_MMHG                50.0F                                              ///< +/- offset from start pressure that defines a range to keep PBo in during dialysate dialyzer prime state.
+#define VENOUS_PRESSURE_DIALSYATE_LINE_OCCLUSION_MMHG       -15.0F                                             ///< Measured venous pressure indicates possible clamping/occlusion during dialysate priming.
 #define DPO_RATE_STEP_PER_SEC_DIALYSATE_PRIME_ML_MIN        1                                                  ///< DPo rate step to maintain pressure during dialysate dialyzer prime state.
 
 #define VENOUS_PRESSURE_BUBBLE_CLEAR_MAX_MMHG               ( 200.0F )                                         ///< Maximum venous pressure reading (in mmHg) for bubble clear.
@@ -143,6 +144,7 @@
 static F32 minimumReservoirVolume;                              ///< Minimum reservoir volume in mL.
 static U32 steadyVolumeCount;                                   ///< Use to keep track the number of dVolume/dt < Threshold
 static BOOL bubbleClearEnded;                                   ///< Bubble clear ended boolean signal.
+static BOOL primeDialysateOcclusionDetected;                    ///< flag used when dialysate occlusion alarm set
 
 // ********** private function prototypes **********
 
@@ -181,6 +183,7 @@
     primePauseStartTime              = 0;
     primeStatusBroadcastTimerCounter = 0;
     bubbleClearEnded                 = FALSE;
+    primeDialysateOcclusionDetected  = FALSE;
 }
 
 /*********************************************************************//**
@@ -818,6 +821,8 @@
     if ( TRUE == didTimeout( steadyVolumeSamplingStartTime, LOAD_CELL_STEADY_VOLUME_SAMPLING_TIME ) )
     {
         F32 venPres                = getFilteredVenousPressure();
+        F32 measuredDialInFlow     = getDGRawDialysateFlowRateLMin() * ML_PER_LITER;
+        BOOL lowFlow               = ( measuredDialInFlow <  MIN_DG_DIAL_FLOW_RATE ? TRUE : FALSE );
 
         if ( venPres > ( primeDialysateDialyzerStartVenPres + PRESSURE_OFFSET_DIALYSATE_PRIME_MMHG ) )
         {
@@ -829,6 +834,20 @@
             primeDialysateDialyzerDPoRate -= DPO_RATE_STEP_PER_SEC_DIALYSATE_PRIME_ML_MIN;
             setDialOutPumpTargetRate( primeDialysateDialyzerDPoRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
         }
+
+        // if dialysate line is clamped for some reasons, raise an alarm based on the measured venous pressure and raw flow rate.
+        if ( ( venPres <= VENOUS_PRESSURE_DIALSYATE_LINE_OCCLUSION_MMHG ) && ( TRUE == lowFlow ) )
+        {
+            SET_ALARM_WITH_2_F32_DATA( ALARM_ID_HD_PRIME_DIALYSATE_LINE_OCCLUSION, venPres, measuredDialInFlow );
+            primeDialysateOcclusionDetected = TRUE;
+        }
+        else if ( TRUE == primeDialysateOcclusionDetected )
+        {
+            // after clearance of occlusion, start the blood side priming due to any air bubbles collected prior.
+            state = HD_PRIME_SALINE_SETUP_STATE;
+            primeDialysateOcclusionDetected = FALSE;
+        }
+
         steadyVolumeSamplingStartTime = getMSTimerCount();
     }