Index: firmware/App/Modes/Prime.c
===================================================================
diff -u -r34d0843fa73e79ba3b085dd4aaa393a1ec126fd4 -r427b37ad929a8d88b5fcb9ae21a4f4146ffd2fef
--- firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 34d0843fa73e79ba3b085dd4aaa393a1ec126fd4)
+++ firmware/App/Modes/Prime.c	(.../Prime.c)	(revision 427b37ad929a8d88b5fcb9ae21a4f4146ffd2fef)
@@ -8,7 +8,7 @@
 * @file    Prime.c
 *
 * @author  (last)      Michael Garthwaite
-* @date    (last)      21-Oct-2022
+* @date    (last)      28-Oct-2022
 *
 * @author  (original)  Quang Nguyen
 * @date    (original)  08-Dec-2020
@@ -36,7 +36,7 @@
 
 // ********** private definitions **********
 
-#define MAX_PRIME_TIME                                      ( 15 * SEC_PER_MIN )                               ///< Maximum prime time (in seconds).
+#define MAX_PRIME_TIME                                      ( 30 * SEC_PER_MIN )                               ///< Maximum prime time (in seconds).
 #define PRIME_DATA_PUB_INTERVAL                             ( MS_PER_SECOND / TASK_GENERAL_INTERVAL )          ///< Interval (ms/task time) at which the prime data is published on the CAN bus.
 
 #define BLOOD_PUMP_FAST_FLOW_RATE_PURGE_AIR_ML_MIN          300                                                ///< Blood pump fast flow rate to fill fluid.
@@ -589,8 +589,13 @@
 
     if ( TRUE == getReservoirFillStatus( DG_RESERVOIR_1 ) )
     {
-        cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
+        rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_1;
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
+        cmdSetDGActiveReservoir( &rsrvrCmd );
+
         if ( TRUE == hasDGCompletedReservoirSwitch() )
         {
             U32 dialyzerDialysateVolume = getDialyzerDialysateVolume();
@@ -770,8 +775,13 @@
 
     if ( TRUE == getReservoirFillStatus( DG_RESERVOIR_2 ) )
     {
-        cmdSetDGActiveReservoir( DG_RESERVOIR_2 );
+        DG_SWITCH_RSRVRS_CMD_T rsrvrCmd;
 
+        rsrvrCmd.reservoirID            = (U32)DG_RESERVOIR_1;
+        rsrvrCmd.useLastTrimmerHeaterDC = FALSE;
+
+        cmdSetDGActiveReservoir( &rsrvrCmd );
+
         if ( TRUE == hasDGCompletedReservoirSwitch() )
         {
             signalBloodPumpHardStop();