Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -rbeeb805ec212b64d188d2ce242c21cb8fb7a9d21 -r5abe83b5825151a96e9684c97e5d8804d6108684
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision beeb805ec212b64d188d2ce242c21cb8fb7a9d21)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 5abe83b5825151a96e9684c97e5d8804d6108684)
@@ -144,7 +144,10 @@
 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.
+#if 0
+// Disabled for release 21. Will be reinstated in release 22.
 static BOOL primeDialysateOcclusionDetected;                    ///< flag used when dialysate occlusion alarm set
+#endif
 
 // ********** private function prototypes **********
 
@@ -183,7 +186,10 @@
     primePauseStartTime              = 0;
     primeStatusBroadcastTimerCounter = 0;
     bubbleClearEnded                 = FALSE;
+#if 0
+// Disabled for release 21. Will be reinstated in release 22.
     primeDialysateOcclusionDetected  = FALSE;
+#endif
 }
 
 /*********************************************************************//**
@@ -821,8 +827,11 @@
     if ( TRUE == didTimeout( steadyVolumeSamplingStartTime, LOAD_CELL_STEADY_VOLUME_SAMPLING_TIME ) )
     {
         F32 venPres                = getFilteredVenousPressure();
+#if 0
+        // Disabled for release 21. Will be reinstated in release 22.
         F32 measuredDialInFlow     = getDGRawDialysateFlowRateLMin() * ML_PER_LITER;
         BOOL lowFlow               = ( measuredDialInFlow <  MIN_DG_DIAL_FLOW_RATE ? TRUE : FALSE );
+#endif
 
         if ( venPres > ( primeDialysateDialyzerStartVenPres + PRESSURE_OFFSET_DIALYSATE_PRIME_MMHG ) )
         {
@@ -834,7 +843,8 @@
             primeDialysateDialyzerDPoRate -= DPO_RATE_STEP_PER_SEC_DIALYSATE_PRIME_ML_MIN;
             setDialOutPumpTargetRate( primeDialysateDialyzerDPoRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
         }
-
+#if 0
+        // Disabled for release 21. Will be reinstated in release 22.
         // if dialysate line is clamped for some reasons, raise an alarm based on the measured venous pressure and raw flow rate.
         if ( ( venPres <= MIN_VENOUS_PRESSURE_DIALSYATE_LINE_OCCLUSION_MMHG ) && ( TRUE == lowFlow ) )
         {
@@ -847,6 +857,7 @@
             state = HD_PRIME_SALINE_SETUP_STATE;
             primeDialysateOcclusionDetected = FALSE;
         }
+#endif
 
         steadyVolumeSamplingStartTime = getMSTimerCount();
     }
Index: firmware/App/Modes/Rinseback.c
===================================================================
diff -u -r4098c86c1059b113b39495f2b771327793ada59a -r5abe83b5825151a96e9684c97e5d8804d6108684
--- firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 4098c86c1059b113b39495f2b771327793ada59a)
+++ firmware/App/Modes/Rinseback.c	(.../Rinseback.c)	(revision 5abe83b5825151a96e9684c97e5d8804d6108684)
@@ -601,7 +601,7 @@
         targetRinsebackVolumePlusAdditional_mL = getRinsebackVolume();
         result = RINSEBACK_STOP_STATE;
     }
-    // Has additional rinseback completed or max additional volume reached
+    // Has additional rinseback completed
     else if ( additionalRinsebackVolume_mL >= TARGET_ADDITIONAL_RINSEBACK_VOLUME_ML )
     {
         result = RINSEBACK_STOP_STATE;