Index: firmware/App/Controllers/BalancingChamber.c
===================================================================
diff -u -r48c4d25d6918813d93165fe4e7fee3bf0c247b7c -r0c0260299f210c9d80e684b1e0605b799880007b
--- firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision 48c4d25d6918813d93165fe4e7fee3bf0c247b7c)
+++ firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision 0c0260299f210c9d80e684b1e0605b799880007b)
@@ -51,6 +51,7 @@
 #define SPENT_DIFF_COUNT_ZERO                       0                                           ///< Zero count difference for spent side fill comparing target count
 #define D48_SPEED_ADJUST_FACTOR                     0.5F                                        ///< D48 speed adjustment factor ( 50% of speed adjustment = 0.5)
 #define D48_SPEED_RANGE_LIMIT                       0.25F                                       ///< D48 speed adjustment range check limit ( D48 speed can vary +/-25% of initial calculated speed)
+#define BICARB_CHAMBER_PERIODIC_FILL_TIME               ( 1 * SEC_PER_MIN * ( MS_PER_SECOND / TASK_GENERAL_INTERVAL ) ) ///< Periodic bicarb chamber fill request 60 sec x 20 = 1200
 #define BAL_CHAMBER_FILL_TIMEOUT_FACTOR             1.5                                         ///< Balancing Chamber fill timeout factor (150% of observed fill count)
 
 /// Payload record structure for balancing chamber switch only request
@@ -89,8 +90,6 @@
 //TODO: remove later once level sensor working
 static U32 bicarbChamberPeriodicFillCounter;                                                    ///< Counter for checking the timeout for drybicart chamber fill request.
 
-static F32 prevSpentDialPressure;                                                               ///< Previous spent side dialysate pressure
-static F32 lastPrevSpentDialPressure;                                                           ///< Last previous spent side dialysate pressure
 static U32 currentBalChamberFillCounter;                                                        ///< Counter (in task interval) to monitor the timing spent for the spent side fill operation.
 static U32 balChamberFillTimeoutCount;                                                          ///< Timeout count (in task interval) to detect BC fill timeout.
 static S32 diffSpentFillCompleteCount;                                                          ///< Difference between spent target fill to actual fill count
@@ -158,8 +157,6 @@
     //TODO:remove once level sensor working
     bicarbChamberPeriodicFillCounter            = 0;
 
-    prevSpentDialPressure                       = 0.0F;
-    lastPrevSpentDialPressure                   = 0.0F;
     currentBalChamberFillCounter                = 0;
     balChamberFillTimeoutCount                  = 0;
     diffSpentFillCompleteCount                  = 0;
@@ -235,6 +232,23 @@
     currentBalChamberSwitchingCounter += 1;
     currentBalChamberFillCounter += 1;
 
+    if ( getTestConfigStatus( TEST_CONFIG_DD_ENABLE_DRY_BICARB ) == TRUE )
+    {
+        //Increment counter for dry bicarb chamber fill
+        bicarbChamberPeriodicFillCounter += 1;
+        // Fill bicarb chamber once every 60secs.
+        if ( bicarbChamberPeriodicFillCounter >= BICARB_CHAMBER_PERIODIC_FILL_TIME )
+        {
+            if ( FALSE == setBicarbChamberFillRequested() )
+            {
+                // TODO
+                //drybicart state machines are combined and so this is not an issue in future
+                //set alarm ?
+            }
+            bicarbChamberPeriodicFillCounter = 0;
+        }
+    }
+
     // execute current balancing chamber exec state
     switch ( balChamberExecState )
     {
@@ -493,7 +507,7 @@
         setHeaterTargetTemperature( D45_HEAT, getD99AverageTemperature() );
     }
 
-    // Check fresh and spent dialysate pressure in range or BC switch only flag set
+    // Check fresh dialysate pressure in range or BC switch only flag set or BC pressure alarms are disabled
     if ( ( ( freshDialPressure >= FRESH_DIAL_PRESSURE_MIN_PSIG ) && ( freshDialPressure <= FRESH_DIAL_PRESSURE_MAX_PSIG ) ) ||
          ( TRUE == getBalChamberSwitchingOnlyStatus() ) || ( TRUE == getTestConfigStatus( TEST_CONFIG_DD_DISABLE_BC_PRESSURE_ALARMS ) ) )
     {