Index: firmware/App/Controllers/Heaters.c
===================================================================
diff -u -r72ba5f3c63325b00306b544b2513c03500919d06 -rcb4d35cc50df2d3cc9e828cd92e53cf456ca9b9d
--- firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision 72ba5f3c63325b00306b544b2513c03500919d06)
+++ firmware/App/Controllers/Heaters.c	(.../Heaters.c)	(revision cb4d35cc50df2d3cc9e828cd92e53cf456ca9b9d)
@@ -654,17 +654,24 @@
  *************************************************************************/
 static void setHeaterDutyCycle( DG_HEATERS_T heater, F32 pwm )
 {
-    if ( DG_PRIMARY_HEATER == heater )
+    if ( heater < NUM_OF_DG_HEATERS )
     {
-        setMainPrimaryHeaterPWM( pwm );
-        setSmallPrimaryHeaterPWM( pwm );
+        if ( DG_PRIMARY_HEATER == heater )
+        {
+            setMainPrimaryHeaterPWM( pwm );
+            setSmallPrimaryHeaterPWM( pwm );
+        }
+        else if ( DG_TRIMMER_HEATER == heater )
+        {
+            setTrimmerHeaterPWM( pwm );
+        }
+
+        heatersStatus[ heater ].dutyCycle = pwm;
     }
-    else if ( DG_TRIMMER_HEATER == heater )
+    else
     {
-        setTrimmerHeaterPWM( pwm );
+        SET_ALARM_WITH_2_U32_DATA( ALARM_ID_DG_SOFTWARE_FAULT, SW_FAULT_ID_HEATERS_INVALID_HEATER_ID_SELECTED, heater );
     }
-
-    heatersStatus[ heater ].dutyCycle = pwm;
 }
 
 /*********************************************************************//**