Index: firmware/App/Controllers/BalancingChamber.c
===================================================================
diff -u -r3d69f9a417c8473a16cc32f37db9b2c96faf7f6a -r788a88e8e9f58c60d3b753ef0ae32b6c7a0757e6
--- firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision 3d69f9a417c8473a16cc32f37db9b2c96faf7f6a)
+++ firmware/App/Controllers/BalancingChamber.c	(.../BalancingChamber.c)	(revision 788a88e8e9f58c60d3b753ef0ae32b6c7a0757e6)
@@ -54,6 +54,7 @@
 #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
 typedef struct
@@ -87,6 +88,7 @@
 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
 static BOOL isSpentFillComplete;
 //TODO: remove later once level sensor working
@@ -149,6 +151,7 @@
     prevSpentDialPressure                       = 0.0F;
     lastPrevSpentDialPressure                   = 0.0F;
     currentBalChamberFillCounter                = 0;
+    balChamberFillTimeoutCount                  = 0;
     diffSpentFillCompleteCount                  = 0;
     isSpentFillComplete                         = FALSE;
     //TODO:remove once level sensor working
@@ -453,6 +456,7 @@
     currentBalChamberSwitchingCounter   = 0;
     balChamberSWState                   = BAL_CHAMBER_SW_STATE1;
     currentBalChamberFillCounter        = 0;
+    balChamberFillTimeoutCount          = 0;
     isBalChamberFillInProgress          = FALSE;
     isPressureStabilizedDuringFill      = FALSE;
     isPressureDroppedDuringFill         = FALSE;
@@ -567,6 +571,12 @@
     freshDialPressure               = getFilteredPressure( D18_PRES );
     spentDialPressure               = getFilteredPressure( D51_PRES );
 
+    // If fill is taking too long, set an alarm for fill timeout
+    if ( ( balChamberFillTimeoutCount > 0 ) && ( currentBalChamberFillCounter > balChamberFillTimeoutCount ) )
+    {
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DD_BC_FILL_TIMEOUT_FAULT, currentBalChamberFillCounter, balChamberFillTimeoutCount );
+    }
+
     // Check fresh dialysate pressure back in range to indicate fresh fill complete.
     if ( ( freshDialPressure >= FRESH_DIAL_PRESSURE_MIN_PSIG ) && ( freshDialPressure <= FRESH_DIAL_PRESSURE_MAX_PSIG ) )
     {
@@ -583,6 +593,12 @@
     // Check both spent and fresh side fill is complete
     if ( ( TRUE == isSpentFillComplete ) && ( TRUE == isPressureStabilizedDuringFill ) || ( FALSE == isFirstCycleBCSwitchingCompleted ) )
     {
+        // On successful completion, learn timeout as 150% of the observed fill count (once per cycle).
+        if ( balChamberFillTimeoutCount == 0U )
+        {
+            balChamberFillTimeoutCount = currentBalChamberFillCounter * BAL_CHAMBER_FILL_TIMEOUT_FACTOR;
+        }
+
         // close the state 1 opened valves
         valveControlForBCState1FillEnd();
         isBalChamberFillInProgress = FALSE;
@@ -671,6 +687,7 @@
     isPressureDroppedDuringFill         = FALSE;
     balChamberSWState                   = BAL_CHAMBER_SW_STATE2;
     currentBalChamberFillCounter        = 0;
+    balChamberFillTimeoutCount          = 0;
     isSpentFillComplete                 = FALSE;
     lastPrevSpentDialPressure           = 0.0F;
     prevSpentDialPressure               = 0.0F;
@@ -739,12 +756,24 @@
         }
     }
 
+    // If fill is taking too long, set an alarm for fill timeout
+    if ( ( balChamberFillTimeoutCount > 0 ) && ( currentBalChamberFillCounter > balChamberFillTimeoutCount ) )
+    {
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DD_BC_FILL_TIMEOUT_FAULT, currentBalChamberFillCounter, balChamberFillTimeoutCount );
+    }
+
     // Spent side of balancing chamber fill is complete or not
     checkSpentFillComplete( spentDialPressure );
 
     // Check switching cycle time or pressure check for valve closure
     if ( ( TRUE == isSpentFillComplete ) && ( TRUE == isPressureStabilizedDuringFill ) || ( FALSE == isFirstCycleBCSwitchingCompleted ) )
     {
+        // On successful completion, learn timeout as 150% of the observed fill count (once per cycle).
+        if ( balChamberFillTimeoutCount == 0U )
+        {
+            balChamberFillTimeoutCount = currentBalChamberFillCounter * BAL_CHAMBER_FILL_TIMEOUT_FACTOR;
+        }
+
         // close the valves
         valveControlForBCState2FillEnd();
         isBalChamberFillInProgress = FALSE;