diff --git a/config.h.dist b/config.h.dist
index c5fb5b3..ce3a6c4 100644
--- a/config.h.dist
+++ b/config.h.dist
@@ -171,6 +171,7 @@
 // OC2A												DIO11
 // OC2B												DIO3
 
+// comment out the ones you don't have
 #define	HEATER_PIN						DIO6
 #define	HEATER_PWM						OCR0A
 
diff --git a/gcode.c b/gcode.c
index 3a83e93..40f257c 100644
--- a/gcode.c
+++ b/gcode.c
@@ -176,9 +176,11 @@ void scan_char(uint8_t c) {
 					// but it takes less code, less memory and loses no precision if we do it here instead
 					if ((next_target.M == 104) || (next_target.M == 109))
 						next_target.S = decfloat_to_int(&read_digit, 4, 1);
+					#ifdef	HEATER_PIN
 					// if this is heater PID stuff, multiply by PID_SCALE because we divide by PID_SCALE later on
 					else if ((next_target.M >= 130) && (next_target.M <= 132))
 						next_target.S = decfloat_to_int(&read_digit, PID_SCALE, 1);
+					#endif
 					else
 						next_target.S = decfloat_to_int(&read_digit, 1, 1);
 					if (debug_flags & DEBUG_ECHO)
@@ -617,6 +619,7 @@ void process_gcode_command(GCODE_COMMAND *gcmd) {
 				sersendf_P("X:%ld,Y:%ld,Z:%ld,E:%ld,F:%ld\n", current_position.X, current_position.Y, current_position.Z, current_position.E, current_position.F);
 			 	break;
 
+			#ifdef	HEATER_PIN
 			// M130- heater P factor
 			case 130:
 				if (gcmd->seen_S)
@@ -641,6 +644,7 @@ void process_gcode_command(GCODE_COMMAND *gcmd) {
 			case 134:
 				heater_save_settings();
 				break;
+			#endif	/* HEATER_PIN */
 
 			#ifdef	DEBUG
 			// M140- echo off
diff --git a/heater.c b/heater.c
index bc63321..320d3c9 100644
--- a/heater.c
+++ b/heater.c
@@ -1,5 +1,7 @@
 #include	"heater.h"
 
+#ifdef HEATER_PIN
+
 #include	<avr/eeprom.h>
 
 #include	"sersendf.h"
@@ -101,3 +103,5 @@ void heater_tick(int16_t current_temp, int16_t target_temp) {
 		disable_heater();
 	#endif
 }
+
+#endif	/* HEATER_PIN */
\ No newline at end of file
diff --git a/heater.h b/heater.h
index 230bd6f..612da2f 100644
--- a/heater.h
+++ b/heater.h
@@ -3,6 +3,8 @@
 
 #include	"config.h"
 
+#ifdef HEATER_PIN
+
 #ifdef	HEATER_PWM
 	#define	enable_heater()			{ TCCR0A |=  MASK(COM0A1); }
 	#define	disable_heater()		{ TCCR0A &= ~MASK(COM0A1); }
@@ -26,4 +28,14 @@ void heater_save_settings(void);
 void heater_tick(int16_t current_temp, int16_t target_temp);
 uint8_t	temp_achieved(void);
 
+#else	/* HEATER_PIN */
+
+// if there is no heater pin, there is no heater
+#define enable_heater()					/* empty */
+#define disable_heater()				/* empty */
+#define heater_init()						/* empty */
+#define heater_save_settings()	/* empty */
+#define heater_tick(p1, p2)			/* empty */
+
+#endif 	/* HEATER_PIN */
 #endif	/* _HEATER_H */