Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -rf53ecc014c076fc476e7963b67d688b7233579ee -r8747e947a7bc52dc3a4fb1346935740e08f5e974
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision f53ecc014c076fc476e7963b67d688b7233579ee)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision 8747e947a7bc52dc3a4fb1346935740e08f5e974)
@@ -7,8 +7,8 @@
 *
 * @file    ModeStandby.c
 *
-* @author  (last)      Sean Nash
-* @date    (last)      04-May-2023
+* @author  (last)      Michael Garthwaite
+* @date    (last)      16-May-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -147,6 +147,7 @@
     resetDialInPumpRotorCount();
     resetPreLoadStatus();
     setVenousBubbleDetectionEnabled( FALSE );
+    setCurrentSubState( NO_SUB_STATE );
 
     // Set user alarm recovery actions allowed in this mode
     setAlarmUserActionEnabled( ALARM_USER_ACTION_RESUME, FALSE );
@@ -198,6 +199,15 @@
 
     handleDisinfectCancel( stop );
 
+    // if no active alarms anymore, restore to default valve states for standby mode
+    if ( ( FALSE == doesAlarmStatusIndicateStop() ) && ( VALVE_POSITION_C_CLOSE == getValvePosition( VDI ) ) )
+    {
+        setValvePosition( VDI, VALVE_POSITION_A_INSERT_EJECT );
+        setValvePosition( VDO, VALVE_POSITION_A_INSERT_EJECT );
+        setValvePosition( VBA, VALVE_POSITION_A_INSERT_EJECT );
+        setValvePosition( VBV, VALVE_POSITION_A_INSERT_EJECT );
+    }
+
     // State machine to get DG to prep a reservoir so we can start a treatment
     switch ( currentStandbyState )
     {
@@ -355,7 +365,27 @@
  *************************************************************************/
 void signalAlarmActionToStandbyMode( ALARM_ACTION_T action )
 {
-    // Alarm actions not handled in Standby mode
+    switch ( action )
+    {
+        case ALARM_ACTION_STOP:
+            // Pumps should be off
+            signalBloodPumpHardStop();
+            signalDialInPumpHardStop();
+            signalDialOutPumpHardStop();
+            stopSyringePump();
+
+            // Set valves to safe positions
+            setValveAirTrap( STATE_CLOSED );
+            setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
+            setValvePosition( VDO, VALVE_POSITION_C_CLOSE );
+            setValvePosition( VBA, VALVE_POSITION_C_CLOSE );
+            setValvePosition( VBV, VALVE_POSITION_C_CLOSE );
+            break;
+
+        default:
+            // do not handle other actions in standby mode
+            break;
+    }
 }
 
 /*********************************************************************//**