Index: firmware/App/Modes/ModeHeatDisinfect.c
===================================================================
diff -u -r5315092604c1a6f4ec8ba1339809bd0099f921da -r3d87e97b9345aec63ca88d741e3bcd548f90422b
--- firmware/App/Modes/ModeHeatDisinfect.c	(.../ModeHeatDisinfect.c)	(revision 5315092604c1a6f4ec8ba1339809bd0099f921da)
+++ firmware/App/Modes/ModeHeatDisinfect.c	(.../ModeHeatDisinfect.c)	(revision 3d87e97b9345aec63ca88d741e3bcd548f90422b)
@@ -7,8 +7,8 @@
 *
 * @file    ModeHeatDisinfect.c
 *
-* @author  (last)      Dara Navaei
-* @date    (last)      04-May-2023
+* @author  (last)      Michael Garthwaite
+* @date    (last)      16-May-2023
 *
 * @author  (original)  Sean
 * @date    (original)  20-Apr-2020
@@ -95,7 +95,7 @@
 #define HEAT_DISINFECT_MAX_RO_PRESSURE_PSI         30                                                          ///< Heat disinfect maximum RO pressure in psi.
 #define HEAT_DISINFECT_START_TEMP_TIMEOUT_MS       ( 4 * MIN_PER_HOUR * SEC_PER_MIN * MS_PER_SECOND )          ///< Heat disinfect reaching to minimum temperature timeout in milliseconds.
 #define RSRVRS_TARGET_VOL_OUT_TIMEOUT_MS           ( 5 * MS_PER_SECOND )                                       ///< Reservoirs 1 & 2 maximum volume out of range timeout during heat disinfect.
-#define RSRVRS_MAX_TARGET_VOL_CHANGE_ML            100.0F                                                      ///< Reservoirs 1 & 2 maximum allowed volume change when full during heat disinfect.
+#define RSRVRS_MAX_TARGET_VOL_CHANGE_ML            150.0F                                                      ///< Reservoirs 1 & 2 maximum allowed volume change when full during heat disinfect.
 #define POST_HEAT_DISINFECT_WAIT_TIME_MS           ( 3 * SEC_PER_MIN * MS_PER_SECOND )                         ///< Heat disinfect final wait time before flushing the system in milliseconds.
 #define HEAT_DISINFECT_MAX_TEMP_GRADIENT_C         15.0F                                                       ///< Heat disinfect maximum allowed temperature gradient in between hottest and coldest sensors.
 #define HEAT_DISINFECT_TEMP_GRAD_OUT_RANGE_TIME_MS ( 0.16 * SEC_PER_MIN * MS_PER_SECOND )                      ///< Heat disinfect temperature gradient out of range timeout in milliseconds.
@@ -318,7 +318,7 @@
     deenergizeActuators( NO_PARK_CONC_PUMPS );
 
     initHeatDisinfectMode();
-
+    setCurrentSubState( NO_SUB_STATE );
     setCPLDCleanLEDColor( CPLD_CLEAN_LED_ORANGE );
 
     return heatDisinfectState;
@@ -1700,7 +1700,7 @@
 
     // NOTE: the drain status should be checked once the reservoirs parameters are initialized. This is to make sure the
     // the timers for stable drain time are initialized prior to using them again
-    isDrainComplete = hasTargetDrainVolumeBeenReached( r, drainSteadyStateTimeout );
+    isDrainComplete = hasTargetDrainToZeroBeenReached( r, drainSteadyStateTimeout );
 
     if ( TRUE == isDrainComplete )
     {