Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r3fa496b611a3a84c8aaa882a1b27762c6bc0024c -rfbb77f3224d4ebe0aecf5aa0f43a753cb9a2c9cf
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 3fa496b611a3a84c8aaa882a1b27762c6bc0024c)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision fbb77f3224d4ebe0aecf5aa0f43a753cb9a2c9cf)
@@ -681,14 +681,17 @@
 {
     HD_PRE_TREATMENT_PRIME_STATE_T state = HD_PRIME_SALINE_CIRC_BLOOD_CIRCUIT_STATE;
 
-    if ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) )
+    if ( ( AIR_TRAP_LEVEL_AIR == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) &&
+         ( ( BUBBLE_DETECTED == getBubbleStatus( ADV ) ) || ( TRUE == didTimeout( noAirDetectedStartTime, NO_AIR_DETECTED_COUNT ) ) ) )
     {
+        signalBloodPumpHardStop();
         purgeAirValvesBloodPumpControl();
         purgeAirTimeOutStartTime = getMSTimerCount();
         state = HD_PRIME_SALINE_PURGE_AIR_STATE;
     }
 
-    if ( TRUE == didTimeout( noAirDetectedStartTime, NO_AIR_DETECTED_COUNT ) )
+    if ( ( TRUE == didTimeout( noAirDetectedStartTime, NO_AIR_DETECTED_COUNT ) ) &&
+         ( AIR_TRAP_LEVEL_FLUID == getAirTrapLevel( AIR_TRAP_LEVEL_SENSOR_LOWER ) ) )
     {
         signalBloodPumpHardStop();
         state = HD_PRIME_RESERVOIR_ONE_FILL_COMPLETE_STATE;