Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r1bff8e530735be63ba557b77557a0bc2ac4b37b2 -rd49b9342b9ae67284d9423224f96838f91f8a1aa
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 1bff8e530735be63ba557b77557a0bc2ac4b37b2)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision d49b9342b9ae67284d9423224f96838f91f8a1aa)
@@ -7,8 +7,8 @@
 *
 * @file    ModePreTreat.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      04-May-2023
+* @author  (last)      Darren Cox
+* @date    (last)      16-May-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -789,6 +789,7 @@
         {
             submodeCompleteTransitionTimeCounter = 0;
             state = HD_PRE_TREATMENT_CART_INSTALL_STATE;
+            setCurrentSubState( NO_SUB_STATE );
             transitionToCartridgeInstallation();
         }
     }
@@ -938,6 +939,8 @@
  *************************************************************************/
 static HD_PRE_TREATMENT_MODE_STATE_T handlePatientConnectionState( void )
 {
+    HD_PRE_TREATMENT_PAT_CONN_STATE_T priorSubState = currentPreTxPatConnState;
+
     switch ( currentPreTxPatConnState )
     {
         case PRE_TREATMENT_PAT_CONN_WAIT_FOR_UF_VOL_STATE:
@@ -961,6 +964,12 @@
             break;
     }
 
+    if ( priorSubState != currentPreTxPatConnState )
+    {
+        setCurrentSubState( (U32)currentPreTxPatConnState );
+        SEND_EVENT_WITH_2_U32_DATA( HD_EVENT_SUB_STATE_CHANGE, priorSubState, currentPreTxPatConnState );
+    }
+
     // handle alarms w/ stop property
     if ( TRUE == doesAlarmStatusIndicateStop() )
     {
@@ -982,22 +991,45 @@
 
 /*********************************************************************//**
  * @brief
+ * The handlePatientConnectionDoorOpened function handles the check
+ * for door opened in pre-treatment patient connection
+ * sub-mode.
+ * @details Inputs: none
+ * @details Outputs: doorOpened
+ * @return none
+ *************************************************************************/
+static void handlePatientConnectionDoorOpened( void )
+{
+    // Look for cartridge door to open (indicating user inverting dialyzer)
+    if ( STATE_OPEN == getSwitchStatus( FRONT_DOOR ) )
+    {
+        doorOpened = TRUE;
+        cmdStopDGTrimmerHeater();
+        signalDialInPumpHardStop();
+    }
+    else
+    {
+        setDialInPumpTargetFlowRate( DIP_PATIENT_CONNECTION_FLOW_RATE_ML_MIN, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
+        cmdStartDGTrimmerHeater();
+    }
+}
+
+/*********************************************************************//**
+ * @brief
  * The handlePatientConnectionWait4UFVolState function handles the wait
  * for ultrafiltration volume setting state of pre-treatment patient connection
  * sub-mode.
  * @details Inputs: setUFVolStatus
- * @details Outputs: setUFVolStatus, doorOpened
+ * @details Outputs: setUFVolStatus
  * @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;
 
-    // Look for cartridge door to open (indicating user inverting dialyzer)
-    if ( STATE_OPEN == getSwitchStatus( FRONT_DOOR ) )
-    {
-        doorOpened = TRUE;
-    }
+    // Look for cartridge door to open and then close (indicating user inverted dialyzer)
+    handlePatientConnectionDoorOpened();
+
     // If UF volume set by user, move on to next state
     if ( TRUE == setUFVolStatus )
     {
@@ -1014,20 +1046,20 @@
  * for dialyzer invert confirmation state of pre-treatment patient connection
  * sub-mode.
  * @details Inputs: doorOpened
- * @details Outputs: doorOpened
+ * @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;
 
     // Look for cartridge door to open and then close (indicating user inverted dialyzer)
-    if ( STATE_OPEN == getSwitchStatus( FRONT_DOOR ) )
-    {
-        doorOpened = TRUE;
-    }
+    handlePatientConnectionDoorOpened();
+
     if ( ( TRUE == doorOpened ) && ( STATE_CLOSED == getSwitchStatus( FRONT_DOOR ) ) )
     {
+        doorClosedRequired( TRUE, TRUE );
+        doorOpened = FALSE;
         nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_USER_CONFIRM_STATE;
     }
 
@@ -1049,7 +1081,7 @@
 
     if ( TRUE == patientConnectionConfirm )
     {
-        doorClosedRequired( TRUE, TRUE );
+        patientConnectionConfirm = FALSE;
         nextState = PRE_TREATMENT_PAT_CONN_WAIT_FOR_TREATMENT_START_STATE;
     }