Index: firmware/App/Modes/ModeStandby.c
===================================================================
diff -u -rdaf4763d6f40baf4cbc2f9d88aba7d9faf588ad6 -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision daf4763d6f40baf4cbc2f9d88aba7d9faf588ad6)
+++ firmware/App/Modes/ModeStandby.c	(.../ModeStandby.c)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -7,8 +7,8 @@
 *
 * @file    ModeStandby.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      27-Sep-2022
+* @author  (last)      Bill Bracken
+* @date    (last)      30-Nov-2022
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -312,6 +312,7 @@
     {
         stopSampleWaterRequest = FALSE;
         setValveState( VSP, VALVE_STATE_CLOSED );
+        setValveState( VPI, VALVE_STATE_CLOSED );
         state = DG_STANDBY_MODE_STATE_FLUSH_FILTER_IDLE;
     }
 
Index: firmware/App/Services/AlarmMgmtSWFaults.h
===================================================================
diff -u -r5e8f96e11c797bddeddfc009c87f20df3b7a8664 -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Services/AlarmMgmtSWFaults.h	(.../AlarmMgmtSWFaults.h)	(revision 5e8f96e11c797bddeddfc009c87f20df3b7a8664)
+++ firmware/App/Services/AlarmMgmtSWFaults.h	(.../AlarmMgmtSWFaults.h)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -140,6 +140,7 @@
     SW_FAULT_ID_INVALID_FPGA_ERROR_GROUP_SELECTED,
     SW_FAULT_ID_INVALID_LED_COLOR_SELECTED,                             // 110
     SW_FAULT_ID_INVALID_SWITCH_SELECTED,
+    SW_FAULT_ID_DG_CHEM_DISINFECT_FLUSH_INVALID_EXEC_STATE,
     SW_FAULT_ID_INVALID_PI_PROFILE_SELECTED,
     SW_FAULT_ID_PI_CTRL_INVALID_STEP_LIMIT,
     NUM_OF_SW_FAULT_IDS
Index: firmware/App/Services/PIControllers.h
===================================================================
diff -u -r5e8f96e11c797bddeddfc009c87f20df3b7a8664 -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Services/PIControllers.h	(.../PIControllers.h)	(revision 5e8f96e11c797bddeddfc009c87f20df3b7a8664)
+++ firmware/App/Services/PIControllers.h	(.../PIControllers.h)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -36,6 +36,7 @@
     PI_CONTROLLER_ID_RO_PUMP_FLOW = 0,              ///< RO Pump controller to flow
     PI_CONTROLLER_ID_DRAIN_PUMP,                    ///< Drain Pump controller
     PI_CONTROLLER_ID_RO_PUMP_MAX_PRES,              ///< RO pump controller to maximum pressure
+    PI_CONTROLLER_ID_DRAIN_PUMP_VOLUME,             ///< Drain pump controller using reservoir volume
     NUM_OF_PI_CONTROLLERS_IDS                       ///< Number of PI controllers
 } PI_CONTROLLER_ID_T;
 
Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -rd3926e5817813a9588b77f6c382940176a5feedc -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision d3926e5817813a9588b77f6c382940176a5feedc)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -877,6 +877,10 @@
             handleStartStopDGChemicalDisinfect( message );
             break;
 
+        case MSG_ID_DG_START_STOP_CHEM_DISINFECT_FLUSH:
+            handleStartStopDGChemicalDisinfectFlush( message );
+            break;
+
         case MSG_ID_UI_DG_SET_RTC_REQUEST:
             handleUIClockSyncRequest( message );
             break;
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -rd3926e5817813a9588b77f6c382940176a5feedc -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision d3926e5817813a9588b77f6c382940176a5feedc)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -1386,6 +1386,41 @@
 }
 
 /*********************************************************************//**
+* @brief
+* The handleStartStopDGChemicalDisinfectFlush function handles a request to start
+* or stop DG chemical disinfect flush mode.
+* @details Inputs: none
+* @details Outputs: message handled
+* @param message a pointer to the message to handle
+* @return none
+*************************************************************************/
+BOOL handleStartStopDGChemicalDisinfectFlush( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+
+    if ( message->hdr.payloadLen == sizeof(BOOL) )
+    {
+        BOOL startingDGChemicalDisinfectFlush;
+
+        memcpy( &startingDGChemicalDisinfectFlush, message->payload, sizeof(BOOL) );
+
+        if ( TRUE == startingDGChemicalDisinfectFlush )
+        {
+            result = startDGChemicalDisinfectFlush();
+        }
+        else
+        {
+            result = stopChemicalDisinfectFlush();
+        }
+    }
+
+    // Respond to request
+    sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_DG_2_HD, result );
+
+    return result;
+}
+
+/*********************************************************************//**
  * @brief
  * The handleTestSetOpModeRequest function handles a request to set the
  * DG operation mode.
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -rd3926e5817813a9588b77f6c382940176a5feedc -rd32847d87534b3273deb7362f598aba60877e7b8
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision d3926e5817813a9588b77f6c382940176a5feedc)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision d32847d87534b3273deb7362f598aba60877e7b8)
@@ -26,6 +26,7 @@
 #include "LoadCell.h"
 #include "MessageSupport.h"
 #include "ModeChemicalDisinfect.h"
+#include "ModeChemicalDisinfectFlush.h"
 #include "ModeFlush.h"
 #include "ModeHeatDisinfect.h"
 #include "MsgQueues.h"
@@ -340,6 +341,9 @@
 // MSG_ID_DG_START_STOP_CHEM_DSINFECT
 BOOL handleStartStopDGChemicalDisinfect( MESSAGE_T *message );
 
+// MSG_ID_DG_START_STOP_CHEM_DISINFECT_FLUSH
+BOOL handleStartStopDGChemicalDisinfectFlush( MESSAGE_T *message );
+
 // MSG_ID_DG_OP_MODE_PUBLISH_INTERVAL_OVERRIDE
 void handleSetDGOpModeBroadcastIntervalOverrideRequest( MESSAGE_T *message );