Index: firmware/App/Modes/ModeFill.c
===================================================================
diff -u -rb3231e63a423fd2d8408c1859e2f58001266a5b5 -r69cab05a9f77dc834cb5f2c93feb7f6db8bd5307
--- firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision b3231e63a423fd2d8408c1859e2f58001266a5b5)
+++ firmware/App/Modes/ModeFill.c	(.../ModeFill.c)	(revision 69cab05a9f77dc834cb5f2c93feb7f6db8bd5307)
@@ -46,11 +46,13 @@
 #define DIALYSATE_BICARB_CONCENTRATE_RATIO              ( 4.06812 / FRACTION_TO_PERCENT_FACTOR )    ///< Ratio between RO water and bicarbonate concentrate.
 
 #define DIALYSATE_FILL_TIME_OUT                         ( 5 * SEC_PER_MIN * MS_PER_SECOND )         ///< Time out period when reservoir is not filled with correct dialysate.
+///< Persistent time interval for concentrate pumps test.
+#define CONCENTRATE_PUMP_TEST_PERSISTENT_INTERVAL       ( 2 * MS_PER_SECOND / TASK_GENERAL_INTERVAL )
 
 #define ACID_BICARB_CONCENTRATE_ADDITION_MULTIPLER      1.06                                        ///< Acid and bicarbonate concentrates make up around 6% to total volume.
 #define FLOW_INTEGRATED_VOLUME_CHECK_TOLERANCE          0.1                                         ///< Flow integrated volume has 10% tolerance compare to load cell reading.
 
-#define CONCENTRATE_TEST_TIME_OUT_MS                    ( 30 * MS_PER_SECOND )                      ///< Concentrate test time out period in ms.
+#define CONCENTRATE_TEST_TIME_OUT_MS                    ( SEC_PER_MIN * MS_PER_SECOND )             ///< Concentrate test time out period in ms.
 #define WATER_QUALITY_CHECK_TIME_OUT_MS                 ( 30 * MS_PER_SECOND )                      ///< Inlet water quality check time out period in ms.
 
 #define CONDUCTIVITY_ERROR_PERSISTENCE_PERIOD_MS        ( 15 * MS_PER_SECOND )                      ///< Persistence period for conductivity error.
@@ -73,6 +75,7 @@
 static U32 waterQualityCheckStartTime;                  ///< Starting time for inlet water quality check.
 static F32 dialysateConductivityTotal;                  ///< Total of dialysate conductivity during fill.
 static U32 dialysateConductivitySampleCount;            ///< Sample count of dialysate conductivity during fill.
+static U32 concentratePumpTestPersistentCount;          ///< Persistent count for concentrate pump testing.
 
 // ********** private function prototypes **********
 
@@ -104,6 +107,7 @@
     concentrateTestStartTime = 0;
     dialysateConductivityTotal = 0.0;
     dialysateConductivitySampleCount = 0;
+    concentratePumpTestPersistentCount = 0;
 
     initPersistentAlarm( ALARM_ID_DIALYSATE_CONDUCTIVITY_OUT_OF_RANGE, CONDUCTIVITY_CLEAR_PERSISTENCE_PERIOD_MS, CONDUCTIVITY_ERROR_PERSISTENCE_PERIOD_MS );
 }
@@ -319,11 +323,19 @@
     if ( TRUE )
 #endif
     {
-        concentrateTestStartTime = getMSTimerCount();
-        requestConcentratePumpsOn( CONCENTRATEPUMPS_CP1_ACID );
-        requestConcentratePumpsOff( CONCENTRATEPUMPS_CP2_BICARB );
-        result = DG_FILL_MODE_STATE_ACID_PUMP_CHECK;
+        if ( concentratePumpTestPersistentCount++ > CONCENTRATE_PUMP_TEST_PERSISTENT_INTERVAL )
+        {
+            concentratePumpTestPersistentCount = 0;
+            concentrateTestStartTime = getMSTimerCount();
+            requestConcentratePumpsOn( CONCENTRATEPUMPS_CP1_ACID );
+            requestConcentratePumpsOff( CONCENTRATEPUMPS_CP2_BICARB );
+            result = DG_FILL_MODE_STATE_ACID_PUMP_CHECK;
+        }
     }
+    else
+    {
+        concentratePumpTestPersistentCount = 0;
+    }
 
     if ( TRUE == didTimeout( concentrateTestStartTime, CONCENTRATE_TEST_TIME_OUT_MS ) )
     {
@@ -354,10 +366,18 @@
     if ( TRUE )
 #endif
     {
-        requestConcentratePumpsOn( CONCENTRATEPUMPS_CP1_ACID );
-        requestConcentratePumpsOn( CONCENTRATEPUMPS_CP2_BICARB );
-        result = DG_FILL_MODE_STATE_DIALYSATE_PRODUCTION;
+        if ( concentratePumpTestPersistentCount++ > CONCENTRATE_PUMP_TEST_PERSISTENT_INTERVAL )
+        {
+            concentratePumpTestPersistentCount = 0;
+            requestConcentratePumpsOn( CONCENTRATEPUMPS_CP1_ACID );
+            requestConcentratePumpsOn( CONCENTRATEPUMPS_CP2_BICARB );
+            result = DG_FILL_MODE_STATE_DIALYSATE_PRODUCTION;
+        }
     }
+    else
+    {
+        concentratePumpTestPersistentCount = 0;
+    }
 
     if ( TRUE == didTimeout( concentrateTestStartTime, CONCENTRATE_TEST_TIME_OUT_MS ) )
     {