Index: firmware/App/Services/Reservoirs.c
===================================================================
diff -u -r1e34d32fcfac88792ed72e55953dee721bacd9d5 -r0b121a7c92a8d86f8369b7094b0bce21389f3747
--- firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 1e34d32fcfac88792ed72e55953dee721bacd9d5)
+++ firmware/App/Services/Reservoirs.c	(.../Reservoirs.c)	(revision 0b121a7c92a8d86f8369b7094b0bce21389f3747)
@@ -19,6 +19,7 @@
 
 #include "ConcentratePumps.h"
 #include "DrainPump.h"
+#include "FPGA.h"
 #include "Heaters.h"
 #include "LoadCell.h"
 #include "MessageSupport.h"
@@ -680,11 +681,22 @@
 
     if ( targetROFlowLPM > 0 )
     {
-        F32 acidTemperature   = acidConcentrateCalRecord.acidConcentrate[ CAL_DATA_ACID_CONCENTRATE_1 ].acidBottleTemperature;
-        F32 bicarbTemperature = bicarbConcentrateCalRecord.bicarbConcentrate[ CAL_DATA_BICARB_CONCENTRATE_1 ].bicarbBottleTemperature;
-
-        priTargetTemp = ( tempTarget * ( tgtTotalFlowLPM / targetROFlowLPM ) ) - ( acidTemperature * ( tgtAicdFlowLPM / targetROFlowLPM ) ) -
-                        ( bicarbTemperature * ( tgtBicarbFlowLPM / targetROFlowLPM ) );
+#ifndef _RELEASE_
+        if ( ( HW_CONFIG_BETA == getHardwareConfigStatus() ) ||
+             ( SW_CONFIG_ENABLE_VALUE == getSoftwareConfigStatus( SW_CONFIG_ENABLE_USING_TPO_FOR_PRIMARY_HEATER_CONTROL ) ) )
+        {
+            // In the later DVT units, TD2 is used for setting the primary heater target temperature. But in the older DVTs as well as the Beta units
+            // the target temperature is calculated by estimating the temperature of the dialysates and volume that is being mixed into the RO water
+            F32 acidTemperature   = acidConcentrateCalRecord.acidConcentrate[ CAL_DATA_ACID_CONCENTRATE_1 ].acidBottleTemperature;
+            F32 bicarbTemperature = bicarbConcentrateCalRecord.bicarbConcentrate[ CAL_DATA_BICARB_CONCENTRATE_1 ].bicarbBottleTemperature;
+            priTargetTemp         = ( tempTarget * ( tgtTotalFlowLPM / targetROFlowLPM ) ) - ( acidTemperature * ( tgtAicdFlowLPM / targetROFlowLPM ) ) -
+                                    ( bicarbTemperature * ( tgtBicarbFlowLPM / targetROFlowLPM ) );
+        }
+        else
+#endif
+        {
+            priTargetTemp = tempTarget;
+        }
     }
 
     return priTargetTemp;