Index: firmware/App/Modes/ModeDrain.c
===================================================================
diff -u -rd442635899db4380b3a405f1537959d25c919c07 -r6190a4ad94521b74164f1e1fbd79ed359c7c27fb
--- firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision d442635899db4380b3a405f1537959d25c919c07)
+++ firmware/App/Modes/ModeDrain.c	(.../ModeDrain.c)	(revision 6190a4ad94521b74164f1e1fbd79ed359c7c27fb)
@@ -17,6 +17,7 @@
 
 #include "ConductivitySensors.h"
 #include "DrainPump.h"
+#include "Heaters.h"
 #include "ModeDrain.h"
 #include "OperationModes.h"
 #include "Pressures.h"
@@ -94,7 +95,12 @@
     // set initial actuator states
     setValveState( VDR, VALVE_STATE_DRAIN_C_TO_NO );
     setDrainPumpTargetRPMDelayed( TARGET_DRAIN_PUMP_RPM, DELAY_DRAIN_PUMP_MS );
+
+    // NOTE: The target flow rate should be set prior to setting the start primary heater
+    // because the initial guess in the heaters driver needs the target flow to calculate
+    // the new PWMs for the main and small primary heaters
     setROPumpTargetFlowRate( TARGET_RO_FLOW_RATE_L, TARGET_RO_PRESSURE_PSI );
+    startPrimaryHeater();
 }
 
 /*********************************************************************//**