Index: firmware/App/Controllers/DGInterface.c
===================================================================
diff -u -r9848d793638e2f613678e60ea7c0f1e7bc31d9eb -r94dab74a6432263dc4569e0cf8f9fa0b01bf1917
--- firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 9848d793638e2f613678e60ea7c0f1e7bc31d9eb)
+++ firmware/App/Controllers/DGInterface.c	(.../DGInterface.c)	(revision 94dab74a6432263dc4569e0cf8f9fa0b01bf1917)
@@ -7,13 +7,15 @@
 *
 * @file    DGInterface.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      03-Apr-2022
+* @author  (last)      Michael Garthwaite
+* @date    (last)      08-Aug-2022
 *
 * @author  (original)  Sean
 * @date    (original)  08-Apr-2020
 *
 ***************************************************************************/
+
+#include <math.h> // To check for NaN
 
 #include "DialInFlow.h"
 #include "Dialysis.h"
@@ -482,6 +484,12 @@
  *************************************************************************/
 void setDialysateFlowData( F32 flowRate )
 {
+    // Check if the sent value by DG is a NaN
+    if ( isnan( flowRate ) )
+    {
+        flowRate = 0.0;
+    }
+
     dgDialysateFlowRateMlMin = flowRate;
     dgDialysateFlowDataFreshFlag = TRUE;
 }
@@ -864,6 +872,19 @@
 
 /*********************************************************************//**
  * @brief
+ * The cmdSetDGToServiceMode function sends a request to DG to transition
+ * to service mode.
+ * @details Inputs: none
+ * @details Outputs: none
+ * @return none
+ *************************************************************************/
+void cmdSetDGToServiceMode( void )
+{
+    sendDGServiceModeRequest();
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleDGCommandResponse function processes the latest DG command response.
  * @details Inputs: none
  * @details Outputs: process command response from DG