Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r8912f5ad5d579105c721ce283c9deaa517eec7e1 -r3a2b4f4cfc9681ea855365ad7bc00bea47e2a3e3
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 8912f5ad5d579105c721ce283c9deaa517eec7e1)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 3a2b4f4cfc9681ea855365ad7bc00bea47e2a3e3)
@@ -8,7 +8,7 @@
 * @file    SystemCommMessages.c
 *
 * @author  (last)      Michael Garthwaite
-* @date    (last)      31-Jul-2023
+* @date    (last)      03-Aug-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -30,6 +30,7 @@
 #include "Heaters.h"
 #include "ModeChemicalDisinfect.h"
 #include "ModeChemicalDisinfectFlush.h"
+#include "ModeDrain.h"
 #include "ModeFill.h"
 #include "ModeFlush.h"
 #include "ModeGenIdle.h"
@@ -77,6 +78,13 @@
     TEST_OVERRIDE_ARRAY_PAYLOAD_T ovRecord;         ///< Test override array payload.
     BOOL flag;                                      ///< Flag.
 } LC_OVERRIDE_PAYLOAD_T;
+
+/// Flow Sensor override payload structure
+typedef struct
+{
+    TEST_OVERRIDE_ARRAY_PAYLOAD_T ovRecord;         ///< Test override array payload.
+    BOOL flag;                                      ///< Flag.
+} FS_OVERRIDE_PAYLOAD_T;
 #pragma pack(pop)
 
 // ********** private data **********
@@ -2306,20 +2314,20 @@
  *************************************************************************/
 void handleTestMeasuredFlowOverrideRequest( MESSAGE_T *message )
 {
-    TEST_OVERRIDE_ARRAY_PAYLOAD_T payload;
+    FS_OVERRIDE_PAYLOAD_T payload;
     BOOL result = FALSE;
 
     // verify payload length
-    if ( sizeof( TEST_OVERRIDE_ARRAY_PAYLOAD_T ) == message->hdr.payloadLen )
+    if ( sizeof( FS_OVERRIDE_PAYLOAD_T ) == message->hdr.payloadLen )
     {
-        memcpy( &payload, message->payload, sizeof( TEST_OVERRIDE_ARRAY_PAYLOAD_T ) );
-        if ( FALSE == payload.reset )
+        memcpy( &payload, message->payload, sizeof( FS_OVERRIDE_PAYLOAD_T ) );
+        if ( FALSE == payload.ovRecord.reset )
         {
-            result = testSetMeasuredFlowRateOverride( payload.index, payload.state.f32 );
+            result = testSetMeasuredFlowRateOverride( payload.ovRecord.index, payload.ovRecord.state.f32, payload.flag );
         }
         else
         {
-            result = testResetMeasuredFlowRateOverride( payload.index );
+            result = testResetMeasuredFlowRateOverride( payload.ovRecord.index );
         }
     }
 
@@ -4885,4 +4893,36 @@
     sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, status );
 }
 
+/*********************************************************************//**
+ * @brief
+ * The handleTestDGDrainModeBroadcastOverrideRequest function handles a request
+ * to override the drain mode state publish interval
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleTestDGDrainModeBroadcastOverrideRequest( MESSAGE_T * message )
+{
+    TEST_OVERRIDE_PAYLOAD_T payload;
+    BOOL result = FALSE;
+
+    // verify payload length
+    if ( sizeof( TEST_OVERRIDE_PAYLOAD_T ) == message->hdr.payloadLen )
+    {
+        memcpy( &payload, message->payload, sizeof( TEST_OVERRIDE_PAYLOAD_T ) );
+        if ( FALSE == payload.reset )
+        {
+            result = testSetDrainModeDataPublishIntervalOverride( payload.state.u32 );
+        }
+        else
+        {
+            result = testResetDrainModeDataPublishIntervalOverride();
+        }
+    }
+
+    // respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
+}
+
 /**@}*/