Index: firmware/App/Modes/Dialysis.c
===================================================================
diff -u -r86dc010eacfdaad879327202bf03336e0c77ead3 -r51fd08fdee3c5471fb0ff598fcae31306374c425
--- firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 86dc010eacfdaad879327202bf03336e0c77ead3)
+++ firmware/App/Modes/Dialysis.c	(.../Dialysis.c)	(revision 51fd08fdee3c5471fb0ff598fcae31306374c425)
@@ -755,6 +755,23 @@
 {
     DIALYSIS_STATE_T result = DIALYSIS_BLOOD_LEAK_ZEROING_STATE;
 
+    // if an air trap fill has started, set BP rate and VBV state accordingly
+    if ( ( airTrapFillInProgress != TRUE ) && ( TRUE == isAirTrapFillInProgress() ) )
+    {
+        // set BP to air trap fill rate if air trap fill has been initiated
+        setBloodPumpTargetFlowRate( AIR_TRAP_FILL_BLOOD_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+        // close VBV for fill
+        setValvePosition( VBV, VALVE_POSITION_C_CLOSE );
+    }
+    // if an air trap fill has completed, restore BP and VBV to blood prime ramp settings
+    if ( ( TRUE == airTrapFillInProgress ) && ( isAirTrapFillInProgress() != TRUE ) )
+    {
+        // restore BP to set blood flow rate
+        setBloodPumpTargetFlowRate( setBloodFlowRate, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_CLOSED_LOOP );
+        // re-open VBV for blood recirculation
+        setValvePosition( VBV, VALVE_POSITION_B_OPEN );
+    }
+
     result = execBloodLeakZeroing();
 
     return result;