Index: firmware/App/Modes/FPModes/ModePreGenPermeate.c
===================================================================
diff -u -r64acabc33ab795591768801f8b443f0da9ee2b98 -ra36dcbc3e2f94d418d8aa54588c836a3adf35e17
--- firmware/App/Modes/FPModes/ModePreGenPermeate.c	(.../ModePreGenPermeate.c)	(revision 64acabc33ab795591768801f8b443f0da9ee2b98)
+++ firmware/App/Modes/FPModes/ModePreGenPermeate.c	(.../ModePreGenPermeate.c)	(revision a36dcbc3e2f94d418d8aa54588c836a3adf35e17)
@@ -448,6 +448,25 @@
 
 /*********************************************************************//**
  * @brief
+ * The validatePreGenPChangeReq function validate whether requested
+ * sub mode change is legal or not.
+ * @details \b Inputs: none
+ * @details \b Outputs: none
+ * @return TRUE if request is legal, FALSE if not.
+ *************************************************************************/
+BOOL validatePreGenPChangeReq( U32 newSubMode )
+{
+    BOOL result = FALSE;
+    LEVEL_STATE_T level = getLevelStatus( P25_LEVL );
+
+    // TODO add validation logic
+    result = TRUE;
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The signalNewPreGenPSubMode function requests transition to a new
  * PreGen Permeate sub mode.
  * @details \b Inputs: none
@@ -457,45 +476,34 @@
 void signalNewPreGenPSubMode( U32 newSubMode )
 {
     FP_PRE_GENP_MODE_STATE_T reqSubMode = (FP_PRE_GENP_MODE_STATE_T)newSubMode;
-    LEVEL_STATE_T level = getLevelStatus( P25_LEVL );
 
     if ( reqSubMode < NUM_OF_FP_PRE_GENW_MODE_STATES )
     {
+        preGenPState = reqSubMode;
+        // handle the pre-requisite if any
         switch ( reqSubMode )
         {
             case FP_PRE_GENP_INLET_PRESSURE_CHECK:
-                preGenPState = FP_PRE_GENP_INLET_PRESSURE_CHECK;
-                setModePreGenPTransition( reqSubMode );
                 break;
 
             case FP_PRE_GENP_FILTER_FLUSH:
-                preGenPState = FP_PRE_GENP_FILTER_FLUSH;
-                setModePreGenPTransition( reqSubMode );
                 break;
 
             case FP_PRE_GENP_PERMEATE_FLUSH:
-                preGenPState = FP_PRE_GENP_PERMEATE_FLUSH;
-                setModePreGenPTransition( reqSubMode );
                 break;
 
             case FP_PRE_GENP_CONCENTRATE_FLUSH:
                 // jump to concentrate flush sub mode only if the permeate tank is full
-                if ( LEVEL_STATE_HIGH == level )
-                {
-                    preGenPState = FP_PRE_GENP_CONCENTRATE_FLUSH;
-                    setModePreGenPTransition( reqSubMode );
-                }
                 break;
 
             case FP_PRE_GENP_VERIFY_WATER:
-                preGenPState = FP_PRE_GENP_VERIFY_WATER;
-                setModePreGenPTransition( reqSubMode );
                 break;
 
             case FP_PRE_GENP_PAUSED:
             default:
                 break;
         }
+        setModePreGenPTransition( reqSubMode );
     }
 }