Index: firmware/App/Modes/ModeDrain.c
===================================================================
diff -u -r4c20f6a3d8c8ff33d2dff4ba27e0732c7614378b -ra1b8dbb69c4bd2f0cc22e62bede7015c9307d378
--- firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision 4c20f6a3d8c8ff33d2dff4ba27e0732c7614378b)
+++ firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision a1b8dbb69c4bd2f0cc22e62bede7015c9307d378)
@@ -1,24 +1,29 @@
 /**************************************************************************
- *
- *  Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
- *
- *  THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
- *  WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
- *
- *  @file ModeDrain.c
- *
- *  @date 20-Dec-2019
- *  @author L. Baloa
- *
- *  @brief Top-level state machine for the drain mode.
- *
- **************************************************************************/
+*
+* Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
+*
+* THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
+* WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
+*
+* @file ModeDrain.c
+*
+* @author (last) Quang Nguyen
+* @date (last) 24-Aug-2020
+*
+* @author (original) Leonardo Baloa
+* @date (original) 20-Dec-2019
+*
+***************************************************************************/
 
+#include "ConductivitySensors.h"
 #include "DrainPump.h"
-#include "LoadCell.h"
 #include "ModeDrain.h"
 #include "OperationModes.h"
+#include "Pressures.h"
 #include "Reservoirs.h"
+#include "ROPump.h"
+#include "TaskGeneral.h"
+#include "TemperatureSensors.h"
 #include "Valves.h"
 
 /**
@@ -28,22 +33,25 @@
 
 // ********** private definitions **********
 
-#define TARGET_DRAIN_PUMP_RPM       2800                        ///< Target drain pump speed (in RPM).
+#define TARGET_DRAIN_PUMP_RPM           1800                                ///< Target drain pump speed (in RPM).
+#define DRAIN_WEIGH_UNCHANGE_TIMEOUT    ( 2 * MS_PER_SECOND )               ///< Time period of unchanged weight during draining before timeout.
 
+#define TARGET_RO_PRESSURE_PSI          130                                 ///< Target pressure for RO pump.
+#define TARGET_RO_FLOW_RATE_L           0.3                                 ///< Target flow rate for RO pump.
+
 // ********** private data **********
 
-static DG_DRAIN_STATE_T drainState = DG_DRAIN_STATE_START;      ///< Currently active drain state.
+static DG_DRAIN_STATE_T drainState = DG_DRAIN_STATE_START;                  ///< Currently active drain state.
 
 // ********** private function prototypes **********
 
 static DG_DRAIN_STATE_T handleDrainState( void );
 
 /*********************************************************************//**
  * @brief
- * The initOpParamsMode function initializes the Drain Mode module.
- * @details
- * Inputs : none
- * Outputs : Operating Parameters Mode module initialized.
+ * The initDrainMode function initializes the drain mode module.
+ * @details Inputs: none
+ * @details Outputs: drainState
  * @return none
  *************************************************************************/
 void initDrainMode( void )
@@ -53,11 +61,9 @@
 
 /*********************************************************************//**
  * @brief
- * The transitionToDrainMode function prepares for transition to drain \n
- * mode.
- * @details
- * Inputs : none
- * Outputs :
+ * The transitionToDrainMode function prepares for transition to drain mode.
+ * @details Inputs: none
+ * @details Outputs: Drain mode initialized
  * @return none
  *************************************************************************/
 void transitionToDrainMode( void )
@@ -67,19 +73,25 @@
 
     // set initial actuator states
     setValveState( VDR, VALVE_STATE_DRAIN_C_TO_NO );
-    setDrainPumpTargetSpeed( TARGET_DRAIN_PUMP_RPM );
+    setDrainPumpTargetRPM( TARGET_DRAIN_PUMP_RPM );
+    setROPumpTargetFlowRate( TARGET_RO_FLOW_RATE_L, TARGET_RO_PRESSURE_PSI );
 }
 
 /*********************************************************************//**
  * @brief
- * The execDrainMode function executes the Drain Mode state machine.
- * @details
- * Inputs : none
- * Outputs :
+ * The execDrainMode function executes the drain mode state machine.
+ * @details Inputs: drainState
+ * @details Outputs: Check water quality, drain mode state machine executed
  * @return current state.
  *************************************************************************/
 U32 execDrainMode( void )
 {
+    // check inlet water conductivity, temperature, pressure, and RO rejection ratio
+    checkInletWaterConductivity();
+    checkInletWaterTemperature();
+    checkInletPressure();
+    checkRORejectionRatio();
+
     // execute current drain state
     switch ( drainState )
     {
@@ -92,7 +104,7 @@
             break;
 
         default:
-            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_SOFTWARE_FAULT, 0, drainState )     // TODO - add s/w fault enum to 1st data param
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_DRAIN_MODE_INVALID_EXEC_STATE, drainState )
             drainState = DG_DRAIN_STATE_START;
             break;
     }
@@ -102,32 +114,20 @@
 
 /*********************************************************************//**
  * @brief
- * The handleDrainState function handles the drain state  of the Drain Mode \n
- * state machine.
- * @details
- * Inputs : none
- * Outputs :
+ * The handleDrainState function handles the drain state  of the drain mode state machine.
+ * @details Inputs: none
+ * @details Outputs: Drain out from reservoir
  * @return the next state
  *************************************************************************/
 static DG_DRAIN_STATE_T handleDrainState( void )
 {
     DG_DRAIN_STATE_T result = DG_DRAIN_STATE_DRAIN;
-    LOAD_CELL_ID_T drainWeightLoadCell = LOAD_CELL_A1;
+    DG_RESERVOIR_ID_T inactiveReservoir = getInactiveReservoir();
 
-    // determine which load cell to use for drain volume - we want weight of inactive reservoir
-#ifndef BETA_V1_BUILD
-    if ( RESERVOIR_1 == getActiveReservoir() )
-#else
-    if ( RESERVOIR_2 == getActiveReservoir() )
-#endif
+    // if we have reached our target drain to volume (by weight) or cannot drain anymore, we are done draining - go back to re-circ mode
+    if ( hasTargetDrainVolumeBeenReached( inactiveReservoir, DRAIN_WEIGH_UNCHANGE_TIMEOUT ) )
     {
-        drainWeightLoadCell = LOAD_CELL_B1;
-    }
-
-    // if we've reached our target drain to volume (by weight), we're done draining - go back to re-circ mode
-    if ( getReservoirDrainVolumeTargetMl() >= getLoadCellFilteredWeight( drainWeightLoadCell ) )
-    {
-        setDrainPumpTargetSpeed( 0 );
+        setDrainPumpTargetRPM( 0 );
         requestNewOperationMode( DG_MODE_CIRC );
     }
 
@@ -136,11 +136,9 @@
 
 /*********************************************************************//**
  * @brief
- * The getCurrentDrainState function returns the current state of the \n
- * drain mode.
- * @details
- * Inputs : drainState
- * Outputs : none
+ * The getCurrentDrainState function returns the current state of the drain mode.
+ * @details Inputs: drainState
+ * @details Outputs: none
  * @return the current state of drain mode.
  *************************************************************************/
 DG_DRAIN_STATE_T getCurrentDrainState( void )