Index: firmware/App/Modes/ModeChemicalDisinfect.c
===================================================================
diff -u -r9490539a39d2bfd8d40558f3c05b09b48f041e6c -rede368b67b0aecd60a9d90546eca353eb6f86e58
--- firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision 9490539a39d2bfd8d40558f3c05b09b48f041e6c)
+++ firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision ede368b67b0aecd60a9d90546eca353eb6f86e58)
@@ -146,7 +146,8 @@
 static U32 rsrvrFillStableTimeCounter = 0;                                                                     ///< Reservoirs fill stable time counter.
 static ALARM_ID_T alarmDetectedPendingTrigger;                                                                 ///< Chemical disinfect alarm to raise.
 static U32 numberOfPostDisinfectRinses = NUM_OF_POST_DISINFECT_RINSES;                                         ///< Number of times to rinse the fluid path after chemical disinfect.
-static U32 primeAcidSteadyStateCounter = 0;
+static U32 primeAcidSteadyStateCounter = 0;                                                                    ///< Prime acid steady state counter.
+static BOOL haveDrainParamsBeenInit;                                                                           ///< Boolean flag to indicate whether the drain parameters have been reset or not.
 
 // ********** private function prototypes **********
 
@@ -192,7 +193,7 @@
  * R1ChemDisinfectVol, R2ChemDisinfectVol, overallChemDisinfectTimer,
  * cancellationMode, rsrvrFillStableTimeCounter, prevChemDisinfectState
  * isPartialDisinfectInProgress, numberOfPostDisinfectRinses,
- * primeAcidSteadyStateCounter, chemDisinfectUIState
+ * primeAcidSteadyStateCounter, chemDisinfectUIState, haveDrainParamsBeenInit
  * @return none
  *************************************************************************/
 void initChemicalDisinfectMode( void )
@@ -214,6 +215,7 @@
     numberOfPostDisinfectRinses  = NUM_OF_POST_DISINFECT_RINSES;
     primeAcidSteadyStateCounter  = 0;
     chemDisinfectUIState         = CHEM_DISINFECT_UI_STATE_NOT_RUNNING;
+    haveDrainParamsBeenInit      = FALSE;
 }
 
 /*********************************************************************//**
@@ -1894,20 +1896,29 @@
 {
     DG_RESERVOIR_STATUS_T status = DG_RESERVOIR_ABOVE_TARGET;
 
+    // If the drain parameters of the reservoir is not initialized, initialize them
+    if ( FALSE == haveDrainParamsBeenInit )
+    {
+        initDrainParameters( r );
+        haveDrainParamsBeenInit = TRUE;
+    }
+
     BOOL isDrainComplete = hasTargetDrainVolumeBeenReached( r, drainSteadyStateTimeout );
 
     if ( TRUE == isDrainComplete )
     {
         // Set the state timer in case it needs to be used for another timeout check
-        stateTimer = getMSTimerCount();
-        status = DG_RESERVOIR_REACHED_TARGET;
+        stateTimer              = getMSTimerCount();
+        haveDrainParamsBeenInit = FALSE;
+        status                  = DG_RESERVOIR_REACHED_TARGET;
     }
     else if ( TRUE == didTimeout( stateTimer, timeout ) )
     {
         // Failed to drain on time. Update the previous chemical disinfect state and transition to basic cancellation
-        prevChemDisinfectState = chemDisinfectState;
+        prevChemDisinfectState      = chemDisinfectState;
+        haveDrainParamsBeenInit     = FALSE;
         alarmDetectedPendingTrigger = ALARM_ID_DG_RESERVOIR_DRAIN_TIMEOUT;
-        status = DG_RESERVOIR_NOT_REACHED_TARGET;
+        status                      = DG_RESERVOIR_NOT_REACHED_TARGET;
     }
 
     return status;