Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -rfadfcc3e667097327fd62202c674ab8727f81110 -r7b88c9005b538ceb13de34212fb5be0a020f0dec
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision fadfcc3e667097327fd62202c674ab8727f81110)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 7b88c9005b538ceb13de34212fb5be0a020f0dec)
@@ -8,7 +8,7 @@
 * @file    SystemCommMessages.c
 *
 * @author  (last)      Dara Navaei
-* @date    (last)      11-Jan-2023
+* @date    (last)      03-Feb-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -4376,4 +4376,68 @@
     sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
 }
 
+#ifndef _RELEASE_
+/*********************************************************************//**
+ * @brief
+ * The handleTestDGNelsonDisinfectSupport function handles a request
+ * to set the Nelson disinfect support mode.
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return none
+ *************************************************************************/
+void handleTestDGNelsonDisinfectSupport( MESSAGE_T *message )
+{
+    U32 payload;
+    BOOL result = FALSE;
+
+    // verify payload length
+    if ( sizeof( U32 ) == message->hdr.payloadLen )
+    {
+        NELSON_SUPPORT_T nelson;
+
+        memcpy( &payload, message->payload, sizeof( U32 ) );
+
+        nelson = (NELSON_SUPPORT_T)payload;
+        result = TRUE;
+
+        switch( nelson )
+        {
+            case NELSON_INOCULATE:
+                setHeatNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_HEAT );
+                break;
+
+            case NELSON_HEAT_DISINFECT:
+                setHeatNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_HEAT );
+                break;
+
+            case NELSON_POS_CONTROL_CHEM_DISINFECT:
+                setChemNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_CHEM );
+                break;
+
+            case NELSON_POS_CONTROL_HEAT_DISINFECT:
+                setHeatNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_HEAT );
+                break;
+
+            case NELSON_CHEM_DISINFECT:
+                setChemNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_CHEM );
+                break;
+
+            case NELSON_DRAIN_SAMPLES:
+                setHeatNelsonSupportMode( nelson );
+                requestNewOperationMode( DG_MODE_HEAT );
+                break;
+        }
+    }
+
+    // respond to request
+    sendTestAckResponseMsg( (MSG_ID_T)message->hdr.msgID, result );
+}
+#endif
+
 /**@}*/