Index: firmware/App/Services/StateServices/Prime.c
===================================================================
diff -u -r25aeff9e9994d2e7aab3b4e6171c56fdac6a01fe -r6c933adfd50a0bc041dc29f4bfa15de5e9f4843a
--- firmware/App/Services/StateServices/Prime.c	(.../Prime.c)	(revision 25aeff9e9994d2e7aab3b4e6171c56fdac6a01fe)
+++ firmware/App/Services/StateServices/Prime.c	(.../Prime.c)	(revision 6c933adfd50a0bc041dc29f4bfa15de5e9f4843a)
@@ -317,6 +317,7 @@
         case PRIME_DC_INITIAL_DIALYSATE_STATE:
             dcInitialPrimeInterval = (U32)( ( ( dialyzerDialysateVolume * 60.0F ) / (F32)TARGET_DIALYSATE_FLOW_RATE + 30.0F ) * (F32)MS_PER_SECOND );
             startProgressSequence( dcInitialPrimeInterval );
+            dcInitialPrimeTimerCtr = 0;
             cmdBypassDialyzer( FALSE );
             stateEntryTimerCtr = getMSTimerCount();
             break;
@@ -356,6 +357,7 @@
             dcReversePrimeDuration = (U32)( ( ( dialyzerDialysateVolume * 0.5F * (F32)SEC_PER_MIN ) / (F32)MAX_UF_RATE ) + 30.0F  ) * (F32)MS_PER_SECOND;
             dcDiscardAndRevPrimeInterval = ( dcDiscardDuration > dcReversePrimeDuration ) ? dcDiscardDuration : dcReversePrimeDuration;
             startProgressSequence( dcDiscardAndRevPrimeInterval );
+            startAirTrapControl();
             signalBloodPumpHardStop();
             cmdDDprimeFluidDiscard( TRUE );
             setValvePosition( H1_VALV, VALVE_POSITION_A_INSERT_EJECT );
@@ -370,6 +372,7 @@
             setValvePosition( H1_VALV, VALVE_POSITION_C_CLOSE );
             setValvePosition( H19_VALV, VALVE_POSITION_C_CLOSE );
 
+            endAirTrapControl();
             setAirPumpState( AIR_PUMP_STATE_OFF, AIR_PUMP_MOTOR_OFF );
             set3WayValveState( H13_VALV, VALVE_3WAY_COMMON_TO_CLOSED_STATE );
             set3WayValveState( H20_VALV, VALVE_3WAY_COMMON_TO_CLOSED_STATE );
@@ -908,7 +911,9 @@
 
     if ( DD_GEND_DIALYSATE_DELIVERY_STATE == getCurrentGenDState() )
     {
-        if ( ++dcInitialPrimeTimerCtr >= dcInitialPrimeInterval )
+        dcInitialPrimeTimerCtr += TASK_GENERAL_INTERVAL;
+
+        if ( dcInitialPrimeTimerCtr >= dcInitialPrimeInterval )
         {
             setPrimeStateTransition( PRIME_WAIT_FOR_AIR_TRAP_FILL_STATE );
             state = PRIME_WAIT_FOR_AIR_TRAP_FILL_STATE;
@@ -1171,11 +1176,14 @@
             elapsedMs = calcTimeSince( primeStartTime );
         }
 
-        elapsedMs = ( elapsedMs > primeTimeCreditMs ) ? ( elapsedMs - primeTimeCreditMs ) : 0;
-
         remainingMs = ( elapsedMs < PRIME_TOTAL_DURATION_INTERVAL ) ?
                       ( PRIME_TOTAL_DURATION_INTERVAL - elapsedMs ) : 0;
 
+        // Updates total remaining time if any sequence done early.
+        remainingMs = ( remainingMs > primeTimeCreditMs ) ?
+                      ( remainingMs - primeTimeCreditMs ) : 0;
+
+
         data.primeState        = (U32)currentPrimeState;
         data.totalDurationSec  = PRIME_TOTAL_DURATION_INTERVAL / MS_PER_SECOND;
         data.countDownSec      = remainingMs / MS_PER_SECOND;