Index: firmware/App/Controllers/PresOccl.c
===================================================================
diff -u -rf9570a9717805d0759622da836a33ee04f3fa40f -rfb1673d2282822995ed233f3e9ea5dfb0567780d
--- firmware/App/Controllers/PresOccl.c	(.../PresOccl.c)	(revision f9570a9717805d0759622da836a33ee04f3fa40f)
+++ firmware/App/Controllers/PresOccl.c	(.../PresOccl.c)	(revision fb1673d2282822995ed233f3e9ea5dfb0567780d)
@@ -679,8 +679,9 @@
             SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_BP_OCCLUSION_OUT_OF_RANGE, bpOccl );
         }
 
-        // Check for BP occlusion
-        if ( bpOccl > ( OCCLUSION_THRESHOLD_OFFSET + bloodPumpOcclusionAfterCartridgeInstall ) )
+        // Check for occlusion in PreTreatment modes when the cartridge is installed
+        // and setOcclusionInstallLevel has been called.
+        if ( MODE_PRET == getCurrentOperationMode() )
         {
             if ( getPreTreatmentSubState() > HD_PRE_TREATMENT_CART_INSTALL_STATE && getDrySelfTestsState() > DRY_SELF_TESTS_START_STATE )
             {
@@ -714,7 +715,8 @@
         }
 
         // Check for venous occlusion
-        if ( ( TRUE == txMode || TRUE == ptxMode ) && ( venPres > getS32TreatmentParamUpperRangeLimit( TREATMENT_PARAM_VEN_PRESSURE_HIGH_LIMIT ) + VENOUS_PRESSURE_OCCL_OFFSET_MMHG ) )
+        if ( ( TRUE == txMode || TRUE == ptxMode ) &&
+             ( venPres > getS32TreatmentParamUpperRangeLimit( TREATMENT_PARAM_VEN_PRESSURE_HIGH_LIMIT ) + VENOUS_PRESSURE_OCCL_OFFSET_MMHG ) )
         {
             if ( TRUE == isPersistentAlarmTriggered( ALARM_ID_HD_VENOUS_LINE_OCCLUSION, TRUE ) )
             {