Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -r56ba1b163b0cbf6953638065b2108f745b17ec8f -rd731f3fda9d25e0d63100f648510e9c8cdd21f89
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision 56ba1b163b0cbf6953638065b2108f745b17ec8f)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision d731f3fda9d25e0d63100f648510e9c8cdd21f89)
@@ -558,14 +558,14 @@
     {
         DG_CMD_RESPONSE_T cmdResponse;
         DG_USAGE_INFO_RECORD_T usageInfo;
+        OPN_CLS_STATE_T concCap = getSwitchStatus( CONCENTRATE_CAP );
+        OPN_CLS_STATE_T diaCap  = getSwitchStatus( DIALYSATE_CAP );
 
         getNVRecord2Driver( GET_USAGE_RECORD, (U08*)&usageInfo, sizeof( DG_USAGE_INFO_RECORD_T ), 0, ALARM_ID_NO_ALARM );
 
-        cmdResponse.commandID   = DG_CMD_START_HEAT_DISINFECT;
-        cmdResponse.rejected    = FALSE;
-        cmdResponse.rejectCode  = DG_CMD_REQUEST_REJECT_REASON_NONE;
-        OPN_CLS_STATE_T concCap = getSwitchStatus( CONCENTRATE_CAP );
-        OPN_CLS_STATE_T diaCap  = getSwitchStatus( DIALYSATE_CAP );
+        cmdResponse.commandID  = DG_CMD_START_HEAT_DISINFECT;
+        cmdResponse.rejected   = FALSE;
+        cmdResponse.rejectCode = DG_CMD_REQUEST_REJECT_REASON_NONE;
 
 #ifndef _RELEASE_
         if ( SW_CONFIG_ENABLE_VALUE == getSoftwareConfigStatus( SW_CONFIG_DISABLE_CAPS_MONITOR ) )
@@ -621,7 +621,7 @@
         cmdResponse.commandID  = DG_CMD_START_CHEM_DISINFECT;
         cmdResponse.rejected   = FALSE;
         cmdResponse.rejectCode = DG_CMD_REQUEST_REJECT_REASON_NONE;
-        OPN_CLS_STATE_T diaCap  = getSwitchStatus( DIALYSATE_CAP );
+        OPN_CLS_STATE_T diaCap = getSwitchStatus( DIALYSATE_CAP );
 
 #ifndef _RELEASE_
         if ( SW_CONFIG_ENABLE_VALUE == getSoftwareConfigStatus( SW_CONFIG_DISABLE_CAPS_MONITOR ) )
@@ -668,20 +668,22 @@
     // Chemical disinfect flush cannot be run in solo mode because the user has to confirm that the acid is inserted or removed
     if ( ( DG_MODE_STAN == getCurrentOperationMode() ) && ( DG_STANDBY_MODE_STATE_IDLE == standbyState ) )
     {
+        OPN_CLS_STATE_T concCap = getSwitchStatus( CONCENTRATE_CAP );
         OPN_CLS_STATE_T diaCap  = getSwitchStatus( DIALYSATE_CAP );
 
 #ifndef _RELEASE_
         if ( SW_CONFIG_ENABLE_VALUE == getSoftwareConfigStatus( SW_CONFIG_DISABLE_CAPS_MONITOR ) )
         {
+            concCap = STATE_CLOSED;
             diaCap  = STATE_CLOSED;
         }
 #endif
 
-        // When chemical disinfect flush is about to be started, dialysate cap must be closed
-        if ( STATE_OPEN == diaCap )
+        if ( ( STATE_OPEN == concCap ) || ( STATE_OPEN == diaCap ) )
         {
             cmdResponse.rejected   = TRUE;
-            cmdResponse.rejectCode = REQUEST_REJECT_REASON_DG_DIALYSATE_CAP_OPEN;
+            cmdResponse.rejectCode = ( STATE_OPEN == getSwitchStatus( DIALYSATE_CAP ) ? REQUEST_REJECT_REASON_DG_DIALYSATE_CAP_OPEN :
+                                                                                        REQUEST_REJECT_REASON_DG_CONCENTRATE_CAP_OPEN );
         }
         else
         {