Index: firmware/App/Modes/StateTxBloodPrime.c
===================================================================
diff -u -r63fdc9a97e335c359fed989383cb56db57dc272f -r9ee205a82fc3bb2b6cdf871a2ef506b7a6caf88f
--- firmware/App/Modes/StateTxBloodPrime.c	(.../StateTxBloodPrime.c)	(revision 63fdc9a97e335c359fed989383cb56db57dc272f)
+++ firmware/App/Modes/StateTxBloodPrime.c	(.../StateTxBloodPrime.c)	(revision 9ee205a82fc3bb2b6cdf871a2ef506b7a6caf88f)
@@ -56,6 +56,9 @@
 /// Tubing portion of blood prime volume to prime the blood side circuit (in mL).
 #define TUBING_BLOOD_PRIME_VOLUME_ML               126
 
+///
+#define BLOOD_PRIME_PAUSE_TIMEOUT_SEC               ( 5 * SEC_PER_MIN )
+
 // ********** private data **********
 
 static BLOOD_PRIME_STATE_T bloodPrimeState;                                     ///< Current state of the blood prime sub-mode.
@@ -72,7 +75,7 @@
 static U32  bloodPrimePublishTimerCtr;                                          ///< Timer counter for determining interval for blood prime status to be published.
 static U32  lastBloodPrimeFlowRate_mL_min;                                      ///< Flow rate prior to pausing blood prime.
 static U32  requestedBloodFlowRate_mL_min;                                      ///< Requested blood flow rate from UI.
-static U32 bloodPrimeStartMS = 0;                                               ///< Start time of Blood Prime (ms timer count)
+static U32  bloodPrimeStartMS = 0;                                              ///< Start time of Blood Prime (ms timer count)
 
 /// Interval (in task intervals) at which to publish blood prime data to CAN bus.
 static OVERRIDE_U32_T bloodPrimePublishInterval = { BLOOD_PRIME_DATA_PUBLISH_INTERVAL, BLOOD_PRIME_DATA_PUBLISH_INTERVAL, BLOOD_PRIME_DATA_PUBLISH_INTERVAL, 0 };
@@ -120,7 +123,7 @@
         estRampSeconds = (F32)MIN_RAMP_TIME_SEC;
     }
     bloodPrimeRampStep_mL = rampRateSpan / estRampSeconds;
-    bloodPrimeStartMS = getMSTimerCount();
+    bloodPrimeStartMS = 0;
 }
 
 /*********************************************************************//**
@@ -275,6 +278,7 @@
         setValvePosition( H1_VALV, VALVE_POSITION_C_CLOSE );
         setValvePosition( H19_VALV, VALVE_POSITION_C_CLOSE );
         result = BLOOD_PRIME_PAUSED_STATE;
+        bloodPrimeStartMS = getMSTimerCount();
     }
     // When UI changes blood flow rate
     else if ( TRUE == pendingFlowChangeRequest )
@@ -332,6 +336,7 @@
         setValvePosition( H1_VALV, VALVE_POSITION_C_CLOSE );
         setValvePosition( H19_VALV, VALVE_POSITION_C_CLOSE );
         result = BLOOD_PRIME_PAUSED_STATE;
+        bloodPrimeStartMS = getMSTimerCount();
     }
     // When UI changes blood flow rate
     else if ( TRUE == pendingFlowChangeRequest )
@@ -503,10 +508,25 @@
         bloodPrimePublishTimerCtr = 0;
         data.targetBloodPrimeVolumeMl = bloodPrimeTargetVolume_mL;
         data.deliveredBloodPrimeVolumeMl = MAX( 0.0, getBloodPrimeVolume() );
-        elapsedMS = calcTimeSince( bloodPrimeStartMS );
-        elapsedSec = elapsedMS / 1000U;
-        data.bloodPrimeTimeoutSec = bloodPrimeStartMS;
-        data.bloodPrimeCountdownSec = elapsedSec;
+        if ( BLOOD_PRIME_PAUSED_STATE == bloodPrimeState )
+        {
+            elapsedMS = calcTimeSince( bloodPrimeStartMS );
+            elapsedSec = elapsedMS / MS_PER_SECOND;
+            data.bloodPrimeTimeoutSec = BLOOD_PRIME_PAUSE_TIMEOUT_SEC;
+            if ( elapsedSec < BLOOD_PRIME_PAUSE_TIMEOUT_SEC )
+            {
+                data.bloodPrimeCountdownSec = BLOOD_PRIME_PAUSE_TIMEOUT_SEC - elapsedSec;
+            }
+            else
+            {
+                data.bloodPrimeCountdownSec = 0;
+            }
+        }
+        else
+        {
+            data.bloodPrimeTimeoutSec = 0;
+            data.bloodPrimeCountdownSec = 0;
+        }
 
         broadcastData( MSG_ID_TD_BLOOD_PRIME_PROGRESS_DATA, COMM_BUFFER_OUT_CAN_TD_BROADCAST, (U08*)&data, sizeof( BLOOD_PRIME_DATA_PAYLOAD_T ) );
     }