Index: firmware/App/Modes/ModeHeatDisinfectActiveCool.c
===================================================================
diff -u -ra12e1212c1cf49011ed8d65beaf9416ca18ffe98 -rbc2f07d1ccac37e4cb18a21bfe096db94e72a151
--- firmware/App/Modes/ModeHeatDisinfectActiveCool.c	(.../ModeHeatDisinfectActiveCool.c)	(revision a12e1212c1cf49011ed8d65beaf9416ca18ffe98)
+++ firmware/App/Modes/ModeHeatDisinfectActiveCool.c	(.../ModeHeatDisinfectActiveCool.c)	(revision bc2f07d1ccac37e4cb18a21bfe096db94e72a151)
@@ -8,7 +8,7 @@
 * @file    ModeHeatDisinfectActiveCool.c
 *
 * @author  (last)      Dara Navaei
-* @date    (last)      16-May-2023
+* @date    (last)      31-May-2023
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  18-Dec-2022
@@ -1108,10 +1108,19 @@
 {
     F32 THdTemperatureC = getTemperatureValue( TEMPSENSORS_HEAT_DISINFECT );
 
-    if ( ( THdTemperatureC <= ROF_ACTIVE_COOL_TARGET_TEMP_C ) && ( FALSE == tempBelowTarget.hasTempTargetTimeBeenSet ) )
+    if ( THdTemperatureC <= ROF_ACTIVE_COOL_TARGET_TEMP_C )
     {
+        // If THd is below the target and the timer for stable temperature has not been set, set it
+        if ( FALSE == tempBelowTarget.hasTempTargetTimeBeenSet )
+        {
+            tempBelowTarget.tempBelowTargetStartTimeMS = getMSTimerCount();
+            tempBelowTarget.hasTempTargetTimeBeenSet   = TRUE;
+        }
+    }
+    else
+    {
+        // The temperature is still above the target so keep reseting the timer
         tempBelowTarget.tempBelowTargetStartTimeMS = getMSTimerCount();
-        tempBelowTarget.hasTempTargetTimeBeenSet   = TRUE;
     }
 
     if ( DG_RESERVOIR_BELOW_TARGET == rsrvrsStatus.rsrvr[ rsrvrID ].rStatus )