Index: firmware/App/Controllers/SyringePump.c
===================================================================
diff -u -r8b791e3252b79d693cb6d959648f85df2e44b709 -r90ac1467b8d858ec3c690f50d87893f3b1778a33
--- firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision 8b791e3252b79d693cb6d959648f85df2e44b709)
+++ firmware/App/Controllers/SyringePump.c	(.../SyringePump.c)	(revision 90ac1467b8d858ec3c690f50d87893f3b1778a33)
@@ -182,6 +182,7 @@
 static BOOL syringePumpContinuousRequested;                                     ///< Flag indicates start or resume of a Heparin continuous delivery operation is requested.
 static BOOL syringePumpDACVrefSetRequested;                                     ///< Flag indicates request to set DAC Vref for force sensor.
 
+static BOOL syringePumpPositionKnown;                                           ///< Flag indicates we know position from a prior retract to home.
 static BOOL syringePumpPlungerFound;                                            ///< Flag indicates plunger was found.
 static BOOL syringePumpPrimeCompleted;                                          ///< Flag indicates prime operation was completed.
 
@@ -247,6 +248,7 @@
     syringePumpSpeedCalcTimerCounter = 0;
     syringePumpRampTimerCtr = 0;
 
+    syringePumpPositionKnown = FALSE;
     syringePumpPlungerFound = FALSE;
     syringePumpPrimeCompleted = FALSE;
 
@@ -434,7 +436,7 @@
 BOOL seekSyringePlunger( void )
 {
     if ( ( SYRINGE_PUMP_OFF_STATE == syringePumpState ) && ( TRUE == isSyringeDetected() ) &&
-         ( TRUE == isSyringePumpHome() ) && ( heparinDeliveryState != HEPARIN_STATE_OFF ) )
+         ( TRUE == syringePumpPositionKnown ) && ( heparinDeliveryState != HEPARIN_STATE_OFF ) )
     {
         syringePumpSetRate = SYRINGE_PUMP_SEEK_RATE;
         syringePumpSeekRequested = TRUE;
@@ -452,7 +454,8 @@
  *************************************************************************/
 BOOL primeSyringePump( void )
 {
-    if ( ( SYRINGE_PUMP_OFF_STATE == syringePumpState ) && ( TRUE == isSyringeDetected() ) && ( heparinDeliveryState != HEPARIN_STATE_OFF ) )
+    if ( ( SYRINGE_PUMP_OFF_STATE == syringePumpState ) && ( TRUE == isSyringeDetected() ) &&
+         ( heparinDeliveryState != HEPARIN_STATE_OFF ) && ( TRUE == syringePumpPlungerFound ) )
     {
         syringePumpSetRate = SYRINGE_PUMP_PRIME_RATE;
         syringePumpPrimeRequested = TRUE;
@@ -478,7 +481,8 @@
     // If valid to start a bolus, kick it off
     if ( ( tgtRate >= MIN_HEPARIN_BOLUS_RATE ) && ( tgtRate <= MAX_HEPARIN_BOLUS_RATE ) && ( FALSE == isSyringePumpHome() ) )
     {
-        if ( ( TRUE == isSyringeDetected() ) && ( SYRINGE_PUMP_OFF_STATE == syringePumpState ) && ( HEPARIN_STATE_STOPPED == heparinDeliveryState ) )
+        if ( ( TRUE == isSyringeDetected() ) && ( TRUE == syringePumpPrimeCompleted ) &&
+             ( SYRINGE_PUMP_OFF_STATE == syringePumpState ) && ( HEPARIN_STATE_STOPPED == heparinDeliveryState ) )
         {
             syringePumpSetRate = tgtRate;
             syringePumpBolusRequested = TRUE;
@@ -988,6 +992,7 @@
         syringePumpHomePositionOffset = getFPGASyringePumpEncoderPosition();
         syringePumpPosition.data = 0;
         syringePumpVolumeStartPosition = 0;
+        syringePumpPositionKnown = TRUE;
         syringePumpVolumeDelivered.data = 0.0;
         syringePumpPlungerFound = FALSE;
         syringePumpPrimeCompleted = FALSE;