Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -rab05daf4dc0398c516845da80c616181a6b62d16 -rf3a862d594f4cef30b08a5bf337189a42c8776d6
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision ab05daf4dc0398c516845da80c616181a6b62d16)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision f3a862d594f4cef30b08a5bf337189a42c8776d6)
@@ -92,6 +92,7 @@
 static BOOL alarmActionResumeReceived = FALSE;                          ///< Flag indicates alarm action resume received.
 
 static HD_PRE_TREATMENT_MODE_STATE_T currentPreTreatmentState;          ///< Current state of pre-treatment mode state machine.
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T currentPreTxPatConnState;      ///< Current state of pre-treatment patient connect sub-mode state machine.
 static BOOL fillReservoirOneStartRequested;                             ///< Flag indicates fill reservoir one has been requested.
 static U32 preTreatmentPublishTimerCounter;                             ///< Pre-treatment data broadcast timer counter used to schedule when to transmit data.
 /// Interval (in task intervals) at which to publish pre-treatment mode data to CAN bus.
@@ -121,6 +122,9 @@
 static HD_PRE_TREATMENT_MODE_STATE_T handlePrimeState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handleRecirculateState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handlePatientConnectionState( void );
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4UFVolState( void );
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4DialyzerInvertState( void );
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4TreatmentStartState( void );
 
 static void execPreTreatmentReservoirMgmt( void );
 static PRE_TREATMENT_RESERVOIR_MGMT_STATE_T handlePreTreatmentReservoirMgmtStartState( void );
@@ -146,6 +150,7 @@
     U32 reservoirIndex = 0;
 
     currentPreTreatmentState = HD_PRE_TREATMENT_WATER_SAMPLE_STATE;
+    currentPreTxPatConnState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_UF_VOL_STATE;
     currentReservoirMgmtState = PRE_TREATMENT_RESERVOIR_MGMT_START_STATE;
     setUFVolStatus = FALSE;
     patientConnectionConfirm = FALSE;
@@ -927,14 +932,26 @@
  *************************************************************************/
 static HD_PRE_TREATMENT_MODE_STATE_T handlePatientConnectionState( void )
 {
-    if ( TRUE == treatmentStartRequested )
+    switch ( currentPreTxPatConnState )
     {
-        DG_RESERVOIR_ID_T const activeRes = getDGActiveReservoir();
+        case PRE_TREATMENT_PAT_CONN_WAIT_FOR_UF_VOL_STATE:
+            currentPreTxPatConnState = handlePatientConnectionWait4UFVolState();
+            break;
 
-        setStartReservoirVolume( activeRes );
-        requestNewOperationMode( MODE_TREA );
+        case PRE_TREATMENT_PAT_CONN_WAIT_FOR_DLZR_INVERT_STATE:
+            currentPreTxPatConnState = handlePatientConnectionWait4DialyzerInvertState();
+            break;
+
+        case PRE_TREATMENT_PAT_CONN_WAIT_FOR_TREATMENT_START_STATE:
+            currentPreTxPatConnState = handlePatientConnectionWait4TreatmentStartState();
+            break;
+
+        default:
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_HD_INVALID_PRE_TREATMENT_PAT_CONN_STATE, currentPreTxPatConnState );
+            break;
     }
 
+    // handle alarms w/ stop property
     if ( TRUE == doesAlarmStatusIndicateStop() )
     {
         signalDialInPumpHardStop();
@@ -949,12 +966,72 @@
         setDialInPumpTargetFlowRate( DIP_PATIENT_CONNECTION_FLOW_RATE_ML_MIN, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
         cmdStartDGTrimmerHeater();
     }
+    else if ( TRUE == treatmentStartRequested )
+    {
+        DG_RESERVOIR_ID_T const activeRes = getDGActiveReservoir();
 
+        setStartReservoirVolume( activeRes );
+        requestNewOperationMode( MODE_TREA );
+    }
+
     return HD_PRE_TREATMENT_PATIENT_CONNECTION_STATE;
 }
 
 /*********************************************************************//**
  * @brief
+ * The handlePatientConnectionWait4UFVolState function handles the wait
+ * for ultrafiltration volume setting state of pre-treatment patient connection
+ * sub-mode.
+ * @details Inputs: none
+ * @details Outputs: none
+ * @return next patient connection state
+ *************************************************************************/
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4UFVolState( void )
+{
+    HD_PRE_TREATMENT_PAT_CONN_STATE_T nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_UF_VOL_STATE;
+
+    if ( TRUE == setUFVolStatus )
+    {
+        setUFVolStatus = FALSE;
+        nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_DLZR_INVERT_STATE;
+    }
+
+    return nextState;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handlePatientConnectionWait4DialyzerInvertState function handles the wait
+ * for dialyzer invert confirmation state of pre-treatment patient connection
+ * sub-mode.
+ * @details Inputs: none
+ * @details Outputs: none
+ * @return next patient connection state
+ *************************************************************************/
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4DialyzerInvertState( void )
+{
+    HD_PRE_TREATMENT_PAT_CONN_STATE_T nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_DLZR_INVERT_STATE;
+
+    return nextState;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handlePatientConnectionWait4TreatmentStartState function handles the wait
+ * for treatment start state of pre-treatment patient connection sub-mode.
+ * @details Inputs: none
+ * @details Outputs: none
+ * @return next patient connection state
+ *************************************************************************/
+static HD_PRE_TREATMENT_PAT_CONN_STATE_T handlePatientConnectionWait4TreatmentStartState( void )
+{
+    HD_PRE_TREATMENT_PAT_CONN_STATE_T nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_TREATMENT_START_STATE;
+
+    return nextState;
+}
+
+/*********************************************************************//**
+ * @brief
  * The execPreTreatmentReservoirMgmt function executes the state machine for
  * reservoir management during pre-treatment mode.
  * @details Inputs: currentReservoirMgmtState