diff --git a/clock.c b/clock.c
index 25b20a4..005129f 100644
--- a/clock.c
+++ b/clock.c
@@ -22,7 +22,6 @@
 	called from clock_10ms(), do not call directly
 */
 static void clock_250ms(void) {
-	#ifndef	NO_AUTO_IDLE
   if (heaters_all_zero()) {
 		if (psu_timeout > (30 * 4)) {
 			power_off();
@@ -36,7 +35,6 @@ static void clock_250ms(void) {
 			SREG = save_reg;
 		}
 	}
-	#endif
 
 	ifclock(clock_flag_1s) {
 		if (DEBUG_POSITION && (debug_flags & DEBUG_POSITION)) {
diff --git a/heater.c b/heater.c
index 60322e2..199aaed 100644
--- a/heater.c
+++ b/heater.c
@@ -438,9 +438,8 @@ void heater_set(heater_t index, uint8_t value) {
 			*(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();
+  if (value)
+    power_on();
 }
 
 /** \brief check wether all heaters are off