diff --git a/gcode_process.c b/gcode_process.c
index 03d5482..89a4a14 100644
--- a/gcode_process.c
+++ b/gcode_process.c
@@ -481,8 +481,6 @@ void process_gcode_command() {
 				if ( ! next_target.seen_P)
 					next_target.P = HEATER_EXTRUDER;
 				temp_set(next_target.P, next_target.S);
-				if (next_target.S)
-					power_on();
 				break;
 
 			case 105:
@@ -533,8 +531,6 @@ void process_gcode_command() {
 				if ( ! next_target.seen_S)
 					break;
         heater_set(next_target.P, next_target.S);
-				if (next_target.S)
-					power_on();
 				break;
 
 			case 110:
@@ -686,7 +682,6 @@ void process_gcode_command() {
 					next_target.P = HEATER_EXTRUDER;
 				if (next_target.seen_S) {
 					heater_set(next_target.P, next_target.S);
-					power_on();
 				}
 				break;
 
@@ -708,8 +703,6 @@ void process_gcode_command() {
 					if ( ! next_target.seen_S)
 						break;
 					temp_set(HEATER_BED, next_target.S);
-					if (next_target.S)
-						power_on();
 				#endif
 				break;
 
diff --git a/heater.c b/heater.c
index d8b315d..55bac09 100644
--- a/heater.c
+++ b/heater.c
@@ -11,6 +11,7 @@
 #include	"arduino.h"
 #include	"debug.h"
 #include	"temp.h"
+#include "pinio.h"
 #include	"crc.h"
 
 #ifndef	EXTRUDER
@@ -436,6 +437,10 @@ void heater_set(heater_t index, uint8_t value) {
 		else
 			*(heaters[index].heater_port) &= ~MASK(heaters[index].heater_pin);
 	}
+
+  // Do this even when the heater is set to
+  // zero to deal with long cool down phases.
+  power_on();
 }
 
 /** \brief turn off all heaters